From 64f140417d818aa374788acc9cb8328165747262 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 12 May 2023 01:24:22 +0900 Subject: modpost: error out if addend_*_rel() is not implemented for REL arch The section mismatch check relies on the relocation entries. For REL, the addend value is implicit, so we need some code to compute it. Currently, EM_386, EM_ARM, and EM_MIPS are supported. This commit makes sure we covered all the cases. I believe the other architectures use RELA, where the explicit r_addend field exists. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d4531d09984d..c1c523adb139 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1628,6 +1628,8 @@ static void section_rel(const char *modname, struct elf_info *elf, if (addend_mips_rel(elf, sechdr, &r)) continue; break; + default: + fatal("Please add code to calculate addend for this architecture\n"); } sym = elf->symtab_start + r_sym; /* Skip special sections */ -- cgit v1.2.3 From d0acc76a49aa917c1a455d11d32d34a01e8b2835 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:19 +0900 Subject: modpost: remove broken calculation of exception_table_entry size find_extable_entry_size() is completely broken. It has awesome comments about how to calculate sizeof(struct exception_table_entry). It was based on these assumptions: - struct exception_table_entry has two fields - both of the fields have the same size Then, we came up with this equation: (offset of the second field) * 2 == (size of struct) It was true for all architectures when commit 52dc0595d540 ("modpost: handle relocations mismatch in __ex_table.") was applied. Our mathematics broke when commit 548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options") introduced the third field. Now, the definition of exception_table_entry is highly arch-dependent. For x86, sizeof(struct exception_table_entry) is apparently 12, but find_extable_entry_size() sets extable_entry_size to 8. I could fix it, but I do not see much value in this code. extable_entry_size is used just for selecting a slightly different error message. If the first field ("insn") references to a non-executable section, The relocation at %s+0x%lx references section "%s" which is not executable, IOW it is not possible for the kernel to fault at that address. Something is seriously wrong and should be fixed. If the second field ("fixup") references to a non-executable section, The relocation at %s+0x%lx references section "%s" which is not executable, IOW the kernel will fault if it ever tries to jump to it. Something is seriously wrong and should be fixed. Merge the two error messages rather than adding even more complexity. Change fatal() to error() to make it continue running and catch more possible errors. Fixes: 548acf19234d ("x86/mm: Expand the exception table logic to allow new handling options") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 60 +++------------------------------------------------ 1 file changed, 3 insertions(+), 57 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c1c523adb139..ba4577aa4f1d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1292,43 +1292,6 @@ static int is_executable_section(struct elf_info* elf, unsigned int section_inde return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); } -/* - * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() - * to know the sizeof(struct exception_table_entry) for the target architecture. - */ -static unsigned int extable_entry_size = 0; -static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) -{ - /* - * If we're currently checking the second relocation within __ex_table, - * that relocation offset tells us the offsetof(struct - * exception_table_entry, fixup) which is equal to sizeof(struct - * exception_table_entry) divided by two. We use that to our advantage - * since there's no portable way to get that size as every architecture - * seems to go with different sized types. Not pretty but better than - * hard-coding the size for every architecture.. - */ - if (!extable_entry_size) - extable_entry_size = r->r_offset * 2; -} - -static inline bool is_extable_fault_address(Elf_Rela *r) -{ - /* - * extable_entry_size is only discovered after we've handled the - * _second_ relocation in __ex_table, so only abort when we're not - * handling the first reloc and extable_entry_size is zero. - */ - if (r->r_offset && extable_entry_size == 0) - fatal("extable_entry size hasn't been discovered!\n"); - - return ((r->r_offset == 0) || - (r->r_offset % extable_entry_size == 0)); -} - -#define is_second_extable_reloc(Start, Cur, Sec) \ - (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) - static void report_extable_warnings(const char* modname, struct elf_info* elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, @@ -1384,22 +1347,9 @@ static void extable_mismatch_handler(const char* modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (!is_executable_section(elf, get_secindex(elf, sym))) { - if (is_extable_fault_address(r)) - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "it is not possible for the kernel to fault\n" - "at that address. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); - else - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "the kernel will fault if it ever tries to\n" - "jump to it. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); - } + else if (!is_executable_section(elf, get_secindex(elf, sym))) + error("%s+0x%lx references non-executable section '%s'\n", + fromsec, (long)r->r_offset, tosec); } static void check_section_mismatch(const char *modname, struct elf_info *elf, @@ -1574,8 +1524,6 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - if (is_second_extable_reloc(start, rela, fromsec)) - find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } @@ -1635,8 +1583,6 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - if (is_second_extable_reloc(start, rel, fromsec)) - find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } -- cgit v1.2.3 From 6c90d36be3e5140c93d3af360d012fa26966304a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:20 +0900 Subject: modpost: remove fromsym info in __ex_table section mismatch warning report_extable_warnings() prints "from" in a pretty form, but we know it is always located in the __ex_table section, i.e. a collection of struct exception_table_entry. It is very likely to fail to get the symbol name and ends up with meaningless message: ... in reference from the (unknown reference) (unknown) to ... Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ba4577aa4f1d..bbe066f7adbc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1297,23 +1297,16 @@ static void report_extable_warnings(const char* modname, struct elf_info* elf, Elf_Rela* r, Elf_Sym* sym, const char* fromsec, const char* tosec) { - Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); - const char* fromsym_name = sym_name(elf, fromsym); Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); const char* tosym_name = sym_name(elf, tosym); - const char* from_pretty_name; - const char* from_pretty_name_p; const char* to_pretty_name; const char* to_pretty_name_p; - get_pretty_name(is_function(fromsym), - &from_pretty_name, &from_pretty_name_p); get_pretty_name(is_function(tosym), &to_pretty_name, &to_pretty_name_p); - warn("%s(%s+0x%lx): Section mismatch in reference from the %s %s%s to the %s %s:%s%s\n", - modname, fromsec, (long)r->r_offset, from_pretty_name, - fromsym_name, from_pretty_name_p, + warn("%s(%s+0x%lx): Section mismatch in reference to the %s %s:%s%s\n", + modname, fromsec, (long)r->r_offset, to_pretty_name, tosec, tosym_name, to_pretty_name_p); if (!match(tosec, mismatch->bad_tosec) && -- cgit v1.2.3 From 6691e6f5fc3e9fa76c9a50970fa851829df7d9f2 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:21 +0900 Subject: modpost: remove get_prettyname() This is the last user of get_pretty_name() - it is just used to distinguish whether the symbol is a function or not. It is not valuable information. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 27 ++------------------------- 1 file changed, 2 insertions(+), 25 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bbe066f7adbc..371891d67175 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,23 +1207,6 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } -static int is_function(Elf_Sym *sym) -{ - if (sym) - return ELF_ST_TYPE(sym->st_info) == STT_FUNC; - else - return -1; -} - -static inline void get_pretty_name(int is_func, const char** name, const char** name_p) -{ - switch (is_func) { - case 0: *name = "variable"; *name_p = ""; break; - case 1: *name = "function"; *name_p = "()"; break; - default: *name = "(unknown reference)"; *name_p = ""; break; - } -} - /* * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. @@ -1299,15 +1282,9 @@ static void report_extable_warnings(const char* modname, struct elf_info* elf, { Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); const char* tosym_name = sym_name(elf, tosym); - const char* to_pretty_name; - const char* to_pretty_name_p; - - get_pretty_name(is_function(tosym), - &to_pretty_name, &to_pretty_name_p); - warn("%s(%s+0x%lx): Section mismatch in reference to the %s %s:%s%s\n", - modname, fromsec, (long)r->r_offset, - to_pretty_name, tosec, tosym_name, to_pretty_name_p); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym_name); if (!match(tosec, mismatch->bad_tosec) && is_executable_section(elf, get_secindex(elf, sym))) -- cgit v1.2.3 From faee9defd8fc376864efb39b87d59f667deeb488 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:22 +0900 Subject: modpost: squash report_extable_warnings() into extable_mismatch_handler() Collect relevant code into one place to clarify all the cases are covered by 'if () ... else if ... else ...'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 40 ++++++++++++++-------------------------- 1 file changed, 14 insertions(+), 26 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 371891d67175..7a9a3ef8ca0d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1275,40 +1275,19 @@ static int is_executable_section(struct elf_info* elf, unsigned int section_inde return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); } -static void report_extable_warnings(const char* modname, struct elf_info* elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char* fromsec, const char* tosec) -{ - Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); - const char* tosym_name = sym_name(elf, tosym); - - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym_name); - - if (!match(tosec, mismatch->bad_tosec) && - is_executable_section(elf, get_secindex(elf, sym))) - fprintf(stderr, - "The relocation at %s+0x%lx references\n" - "section \"%s\" which is not in the list of\n" - "authorized sections. If you're adding a new section\n" - "and/or if this reference is valid, add \"%s\" to the\n" - "list of authorized sections to jump to on fault.\n" - "This can be achieved by adding \"%s\" to \n" - "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); -} - static void extable_mismatch_handler(const char* modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, const char *fromsec) { const char* tosec = sec_name(elf, get_secindex(elf, sym)); + Elf_Sym *tosym = find_elf_symbol(elf, r->r_addend, sym); + const char *tosym_name = sym_name(elf, tosym); sec_mismatch_count++; - report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym_name); if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" @@ -1317,7 +1296,16 @@ static void extable_mismatch_handler(const char* modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (!is_executable_section(elf, get_secindex(elf, sym))) + else if (is_executable_section(elf, get_secindex(elf, sym))) + warn("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not in the list of\n" + "authorized sections. If you're adding a new section\n" + "and/or if this reference is valid, add \"%s\" to the\n" + "list of authorized sections to jump to on fault.\n" + "This can be achieved by adding \"%s\" to\n" + "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", + fromsec, (long)r->r_offset, tosec, tosec, tosec); + else error("%s+0x%lx references non-executable section '%s'\n", fromsec, (long)r->r_offset, tosec); } -- cgit v1.2.3 From fc5fa862c49a4d9e23617fbda7d249d2c1b72e56 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:23 +0900 Subject: modpost: squash report_sec_mismatch() into default_mismatch_handler() report_sec_mismatch() and default_mismatch_handler() are small enough to be merged together. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 55 +++++++++++++++++++-------------------------------- 1 file changed, 20 insertions(+), 35 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 7a9a3ef8ca0d..bb7d1d87bae7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,17 +1207,27 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } -/* - * Print a warning about a section mismatch. - * Try to find symbols near it so user can find it. - * Check whitelist before warning - it may be a false positive. - */ -static void report_sec_mismatch(const char *modname, - const struct sectioncheck *mismatch, - const char *fromsec, - const char *fromsym, - const char *tosec, const char *tosym) +static void default_mismatch_handler(const char *modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { + const char *tosec; + Elf_Sym *to; + Elf_Sym *from; + const char *tosym; + const char *fromsym; + + from = find_elf_symbol2(elf, r->r_offset, fromsec); + fromsym = sym_name(elf, from); + + tosec = sec_name(elf, get_secindex(elf, sym)); + to = find_elf_symbol(elf, r->r_addend, sym); + tosym = sym_name(elf, to); + + /* check whitelist - we may ignore it */ + if (!secref_whitelist(mismatch, fromsec, fromsym, tosec, tosym)) + return; + sec_mismatch_count++; switch (mismatch->mismatch) { @@ -1242,31 +1252,6 @@ static void report_sec_mismatch(const char *modname, } } -static void default_mismatch_handler(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) -{ - const char *tosec; - Elf_Sym *to; - Elf_Sym *from; - const char *tosym; - const char *fromsym; - - from = find_elf_symbol2(elf, r->r_offset, fromsec); - fromsym = sym_name(elf, from); - - tosec = sec_name(elf, get_secindex(elf, sym)); - to = find_elf_symbol(elf, r->r_addend, sym); - tosym = sym_name(elf, to); - - /* check whitelist - we may ignore it */ - if (secref_whitelist(mismatch, - fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, mismatch, - fromsec, fromsym, tosec, tosym); - } -} - static int is_executable_section(struct elf_info* elf, unsigned int section_index) { if (section_index > elf->num_sections) -- cgit v1.2.3 From f4c35484e7f11458c1834b88ee55b746cdabbb09 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:24 +0900 Subject: modpost: clean up is_executable_section() SHF_EXECINSTR is a bit flag (#define SHF_EXECINSTR 0x4). Compare the masked flag to '!= 0'. There is no good reason to stop modpost immediately even if a special section index is given. You will get a section mismatch error anyway. Also, change the return type to bool. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bb7d1d87bae7..0bda2f22c985 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1207,6 +1207,14 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, return near; } +static bool is_executable_section(struct elf_info *elf, unsigned int secndx) +{ + if (secndx > elf->num_sections) + return false; + + return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0; +} + static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela *r, Elf_Sym *sym, const char *fromsec) @@ -1252,14 +1260,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } -static int is_executable_section(struct elf_info* elf, unsigned int section_index) -{ - if (section_index > elf->num_sections) - fatal("section_index is outside elf->num_sections!\n"); - - return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); -} - static void extable_mismatch_handler(const char* modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Rela* r, Elf_Sym* sym, -- cgit v1.2.3 From 856567d5599e7df75d7cad1fef1311d7c1854200 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:25 +0900 Subject: modpost: squash extable_mismatch_handler() into default_mismatch_handler() Merging these two reduces several lines of code. The extable section mismatch is already distinguished by EXTABLE_TO_NON_TEXT. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 84 ++++++++++++++++----------------------------------- 1 file changed, 26 insertions(+), 58 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 0bda2f22c985..49357a716519 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -881,27 +881,14 @@ enum mismatch { * targeting sections in this array (white-list). Can be empty. * * @mismatch: Type of mismatch. - * - * @handler: Specific handler to call when a match is found. If NULL, - * default_mismatch_handler() will be called. - * */ struct sectioncheck { const char *fromsec[20]; const char *bad_tosec[20]; const char *good_tosec[20]; enum mismatch mismatch; - void (*handler)(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec); - }; -static void extable_mismatch_handler(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, - const char *fromsec); - static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data @@ -974,7 +961,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { ".altinstr_replacement", NULL }, .good_tosec = {ALL_TEXT_SECTIONS , NULL}, .mismatch = EXTABLE_TO_NON_TEXT, - .handler = extable_mismatch_handler, } }; @@ -1255,60 +1241,42 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, modname, tosym, tosec); break; case EXTABLE_TO_NON_TEXT: - fatal("There's a special handler for this mismatch type, we should never get here.\n"); + warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", + modname, fromsec, (long)r->r_offset, tosec, tosym); + + if (match(tosec, mismatch->bad_tosec)) + fatal("The relocation at %s+0x%lx references\n" + "section \"%s\" which is black-listed.\n" + "Something is seriously wrong and should be fixed.\n" + "You might get more information about where this is\n" + "coming from by using scripts/check_extable.sh %s\n", + fromsec, (long)r->r_offset, tosec, modname); + else if (is_executable_section(elf, get_secindex(elf, sym))) + warn("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not in the list of\n" + "authorized sections. If you're adding a new section\n" + "and/or if this reference is valid, add \"%s\" to the\n" + "list of authorized sections to jump to on fault.\n" + "This can be achieved by adding \"%s\" to\n" + "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", + fromsec, (long)r->r_offset, tosec, tosec, tosec); + else + error("%s+0x%lx references non-executable section '%s'\n", + fromsec, (long)r->r_offset, tosec); break; } } -static void extable_mismatch_handler(const char* modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char *fromsec) -{ - const char* tosec = sec_name(elf, get_secindex(elf, sym)); - Elf_Sym *tosym = find_elf_symbol(elf, r->r_addend, sym); - const char *tosym_name = sym_name(elf, tosym); - - sec_mismatch_count++; - - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym_name); - - if (match(tosec, mismatch->bad_tosec)) - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is black-listed.\n" - "Something is seriously wrong and should be fixed.\n" - "You might get more information about where this is\n" - "coming from by using scripts/check_extable.sh %s\n", - fromsec, (long)r->r_offset, tosec, modname); - else if (is_executable_section(elf, get_secindex(elf, sym))) - warn("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not in the list of\n" - "authorized sections. If you're adding a new section\n" - "and/or if this reference is valid, add \"%s\" to the\n" - "list of authorized sections to jump to on fault.\n" - "This can be achieved by adding \"%s\" to\n" - "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); - else - error("%s+0x%lx references non-executable section '%s'\n", - fromsec, (long)r->r_offset, tosec); -} - static void check_section_mismatch(const char *modname, struct elf_info *elf, Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); - if (mismatch) { - if (mismatch->handler) - mismatch->handler(modname, elf, mismatch, - r, sym, fromsec); - else - default_mismatch_handler(modname, elf, mismatch, - r, sym, fromsec); - } + if (!mismatch) + return; + + default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec); } static unsigned int *reloc_location(struct elf_info *elf, -- cgit v1.2.3 From dbf7cc2e4e78dfecad02ff17ff5c9971b42da462 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:26 +0900 Subject: modpost: pass 'tosec' down to default_mismatch_handler() default_mismatch_handler() does not need to compute 'tosec' because it is calculated by the caller. Pass it down to default_mismatch_handler() instead of calling sec_name() twice. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 49357a716519..2cc9c2a4aadc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1203,9 +1203,9 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) + Elf_Rela *r, Elf_Sym *sym, const char *fromsec, + const char *tosec) { - const char *tosec; Elf_Sym *to; Elf_Sym *from; const char *tosym; @@ -1214,7 +1214,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, from = find_elf_symbol2(elf, r->r_offset, fromsec); fromsym = sym_name(elf, from); - tosec = sec_name(elf, get_secindex(elf, sym)); to = find_elf_symbol(elf, r->r_addend, sym); tosym = sym_name(elf, to); @@ -1276,7 +1275,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec); + default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec, tosec); } static unsigned int *reloc_location(struct elf_info *elf, -- cgit v1.2.3 From 9990ca35870b7c57d39f8b325d676dfd028035b4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:27 +0900 Subject: modpost: pass section index to find_elf_symbol2() find_elf_symbol2() converts the section index to the section name, then compares the two strings in each iteration. This is slow. It is faster to compare the section indices (i.e. integers) directly. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 34 +++++++++++++++------------------- 1 file changed, 15 insertions(+), 19 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2cc9c2a4aadc..3b7b78e69137 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1169,19 +1169,14 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, * it is, but this works for now. **/ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, - const char *sec) + unsigned int secndx) { Elf_Sym *sym; Elf_Sym *near = NULL; Elf_Addr distance = ~0; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - const char *symsec; - - if (is_shndx_special(sym->st_shndx)) - continue; - symsec = sec_name(elf, get_secindex(elf, sym)); - if (strcmp(symsec, sec) != 0) + if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; @@ -1203,7 +1198,8 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec, + Elf_Rela *r, Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec, const char *tosec) { Elf_Sym *to; @@ -1211,7 +1207,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, const char *tosym; const char *fromsym; - from = find_elf_symbol2(elf, r->r_offset, fromsec); + from = find_elf_symbol2(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); to = find_elf_symbol(elf, r->r_addend, sym); @@ -1267,7 +1263,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) + Elf_Rela *r, Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); @@ -1275,7 +1272,8 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fromsec, tosec); + default_mismatch_handler(modname, elf, mismatch, r, sym, fsecndx, fromsec, + tosec); } static unsigned int *reloc_location(struct elf_info *elf, @@ -1390,12 +1388,11 @@ static void section_rela(const char *modname, struct elf_info *elf, Elf_Rela *rela; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rela *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; @@ -1434,7 +1431,7 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fromsec); + check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); } } @@ -1445,12 +1442,11 @@ static void section_rel(const char *modname, struct elf_info *elf, Elf_Rel *rel; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rel *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; @@ -1493,7 +1489,7 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fromsec); + check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); } } -- cgit v1.2.3 From ac263349b91bf34b7c8419f5645c84b4f88de846 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 15 May 2023 00:27:28 +0900 Subject: modpost: rename find_elf_symbol() and find_elf_symbol2() find_elf_symbol() and find_elf_symbol2() are not good names. Rename them to find_tosym(), find_fromsym(), respectively. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3b7b78e69137..0d2c2aff2c03 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1124,8 +1124,8 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ -static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, + Elf_Sym *relsym) { Elf_Sym *sym; Elf_Sym *near = NULL; @@ -1168,8 +1168,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, * The ELF format may have a better way to detect what type of symbol * it is, but this works for now. **/ -static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx) +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) { Elf_Sym *sym; Elf_Sym *near = NULL; @@ -1207,10 +1207,10 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, const char *tosym; const char *fromsym; - from = find_elf_symbol2(elf, r->r_offset, fsecndx); + from = find_fromsym(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); - to = find_elf_symbol(elf, r->r_addend, sym); + to = find_tosym(elf, r->r_addend, sym); tosym = sym_name(elf, to); /* check whitelist - we may ignore it */ -- cgit v1.2.3 From 17b53f10aba7c17e92bcf713179bc577cba059b7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:06 +0900 Subject: Revert "modpost: skip ELF local symbols during section mismatch check" This reverts commit a4d26f1a0958bb1c2b60c6f1e67c6f5d43e2647b. The variable 'fromsym' never starts with ".L" since commit 87e5b1e8f257 ("module: Sync code of is_arm_mapping_symbol()"). In other words, Pattern 6 is now dead code. Previously, the .LANCHOR1 hid the symbols listed in Pattern 2. 87e5b1e8f257 provided a better solution. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 0d2c2aff2c03..71de14544432 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1034,14 +1034,6 @@ static const struct sectioncheck *section_mismatch( * fromsec = text section * refsymname = *.constprop.* * - * Pattern 6: - * Hide section mismatch warnings for ELF local symbols. The goal - * is to eliminate false positive modpost warnings caused by - * compiler-generated ELF local symbol names such as ".LANCHOR1". - * Autogenerated symbol names bypass modpost's "Pattern 2" - * whitelisting, which relies on pattern-matching against symbol - * names to work. (One situation where gcc can autogenerate ELF - * local symbols is when "-fsection-anchors" is used.) **/ static int secref_whitelist(const struct sectioncheck *mismatch, const char *fromsec, const char *fromsym, @@ -1092,10 +1084,6 @@ static int secref_whitelist(const struct sectioncheck *mismatch, match(fromsym, optim_symbols)) return 0; - /* Check for pattern 6 */ - if (strstarts(fromsym, ".L")) - return 0; - return 1; } -- cgit v1.2.3 From 05bb0704672dec59cbdc6b901130098ecfe7a846 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:09 +0900 Subject: modpost: remove unused argument from secref_whitelist() secref_whitelist() does not use the argument 'mismatch'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 71de14544432..c0b262b68d50 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1035,8 +1035,7 @@ static const struct sectioncheck *section_mismatch( * refsymname = *.constprop.* * **/ -static int secref_whitelist(const struct sectioncheck *mismatch, - const char *fromsec, const char *fromsym, +static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ @@ -1202,7 +1201,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, tosym = sym_name(elf, to); /* check whitelist - we may ignore it */ - if (!secref_whitelist(mismatch, fromsec, fromsym, tosec, tosym)) + if (!secref_whitelist(fromsec, fromsym, tosec, tosym)) return; sec_mismatch_count++; -- cgit v1.2.3 From a23e7584ecf33df2b27ac176185c7b030ab0736f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:11 +0900 Subject: modpost: unify 'sym' and 'to' in default_mismatch_handler() find_tosym() takes 'sym' and stores the return value to another variable 'to'. You can use the same variable because we want to replace the original one when appropriate. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c0b262b68d50..9290e0f804cf 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1185,11 +1185,10 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, + Elf_Rela *r, Elf_Sym *tsym, unsigned int fsecndx, const char *fromsec, const char *tosec) { - Elf_Sym *to; Elf_Sym *from; const char *tosym; const char *fromsym; @@ -1197,8 +1196,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, from = find_fromsym(elf, r->r_offset, fsecndx); fromsym = sym_name(elf, from); - to = find_tosym(elf, r->r_addend, sym); - tosym = sym_name(elf, to); + tsym = find_tosym(elf, r->r_addend, tsym); + tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ if (!secref_whitelist(fromsec, fromsym, tosec, tosym)) @@ -1233,7 +1232,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)r->r_offset, tosec, modname); - else if (is_executable_section(elf, get_secindex(elf, sym))) + else if (is_executable_section(elf, get_secindex(elf, tsym))) warn("The relocation at %s+0x%lx references\n" "section \"%s\" which is not in the list of\n" "authorized sections. If you're adding a new section\n" -- cgit v1.2.3 From 04ed3b476306c1b4c6e544e40d10f477c8193435 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:12 +0900 Subject: modpost: replace r->r_offset, r->r_addend with faddr, taddr r_offset/r_addend holds the offset address from/to which a symbol is referenced. It is unclear unless you are familiar with ELF. Rename them to faddr, taddr, respectively. The prefix 'f' means 'from', 't' means 'to'. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 9290e0f804cf..c339d9eda402 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1185,18 +1185,18 @@ static bool is_executable_section(struct elf_info *elf, unsigned int secndx) static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *tsym, - unsigned int fsecndx, const char *fromsec, - const char *tosec) + Elf_Sym *tsym, + unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, + const char *tosec, Elf_Addr taddr) { Elf_Sym *from; const char *tosym; const char *fromsym; - from = find_fromsym(elf, r->r_offset, fsecndx); + from = find_fromsym(elf, faddr, fsecndx); fromsym = sym_name(elf, from); - tsym = find_tosym(elf, r->r_addend, tsym); + tsym = find_tosym(elf, taddr, tsym); tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ @@ -1223,7 +1223,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, break; case EXTABLE_TO_NON_TEXT: warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)r->r_offset, tosec, tosym); + modname, fromsec, (long)faddr, tosec, tosym); if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" @@ -1231,7 +1231,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "Something is seriously wrong and should be fixed.\n" "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", - fromsec, (long)r->r_offset, tosec, modname); + fromsec, (long)faddr, tosec, modname); else if (is_executable_section(elf, get_secindex(elf, tsym))) warn("The relocation at %s+0x%lx references\n" "section \"%s\" which is not in the list of\n" @@ -1240,17 +1240,18 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, "list of authorized sections to jump to on fault.\n" "This can be achieved by adding \"%s\" to\n" "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", - fromsec, (long)r->r_offset, tosec, tosec, tosec); + fromsec, (long)faddr, tosec, tosec, tosec); else error("%s+0x%lx references non-executable section '%s'\n", - fromsec, (long)r->r_offset, tosec); + fromsec, (long)faddr, tosec); break; } } static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, - unsigned int fsecndx, const char *fromsec) + Elf_Sym *sym, + unsigned int fsecndx, const char *fromsec, + Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); @@ -1258,8 +1259,9 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, r, sym, fsecndx, fromsec, - tosec); + default_mismatch_handler(modname, elf, mismatch, sym, + fsecndx, fromsec, faddr, + tosec, taddr); } static unsigned int *reloc_location(struct elf_info *elf, @@ -1417,7 +1419,8 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); + check_section_mismatch(modname, elf, sym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1475,7 +1478,8 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; - check_section_mismatch(modname, elf, &r, sym, fsecndx, fromsec); + check_section_mismatch(modname, elf, sym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } -- cgit v1.2.3 From a9bb3e5d57293773d7f925dd07e45f6e13e94947 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:13 +0900 Subject: modpost: remove is_shndx_special() check from section_rel(a) This check is unneeded. Without it, sec_name() will returns the null string "", then section_mismatch() will return immediately. Anyway, special section indices rarely appear in these loops. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 16 ++++------------ scripts/mod/modpost.h | 5 ----- 2 files changed, 4 insertions(+), 17 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c339d9eda402..1018cd9ced71 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1372,7 +1372,6 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) static void section_rela(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rela *rela; Elf_Rela r; unsigned int r_sym; @@ -1415,11 +1414,8 @@ static void section_rela(const char *modname, struct elf_info *elf, continue; break; } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - check_section_mismatch(modname, elf, sym, + + check_section_mismatch(modname, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1427,7 +1423,6 @@ static void section_rela(const char *modname, struct elf_info *elf, static void section_rel(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rel *rel; Elf_Rela r; unsigned int r_sym; @@ -1474,11 +1469,8 @@ static void section_rel(const char *modname, struct elf_info *elf, default: fatal("Please add code to calculate addend for this architecture\n"); } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - check_section_mismatch(modname, elf, sym, + + check_section_mismatch(modname, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 1178f40a73f3..b1e2d95f8047 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -151,11 +151,6 @@ struct elf_info { Elf32_Word *symtab_shndx_stop; }; -static inline int is_shndx_special(unsigned int i) -{ - return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE; -} - /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ static inline unsigned int get_secindex(const struct elf_info *info, const Elf_Sym *sym) -- cgit v1.2.3 From d4323e83505247d2aca1e2488f69da9aab8ad03f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:21 +0900 Subject: modpost: merge fromsec=DATA_SECTIONS entries in sectioncheck table You can merge these entries. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 1018cd9ced71..21417a4a7655 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -900,12 +900,7 @@ static const struct sectioncheck sectioncheck[] = { }, { .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_INIT, }, { -- cgit v1.2.3 From abc23979ac90396c5a5dff03dcea198b5bd0c50d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:22 +0900 Subject: modpost: merge bad_tosec=ALL_EXIT_SECTIONS entries in sectioncheck table There is no distinction between TEXT_TO_ANY_EXIT and DATA_TO_ANY_EXIT. Just merge them. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 21417a4a7655..cc4cf40a360f 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -859,8 +859,7 @@ static const char *const optim_symbols[] = { "*.constprop.*", NULL }; enum mismatch { TEXT_TO_ANY_INIT, DATA_TO_ANY_INIT, - TEXT_TO_ANY_EXIT, - DATA_TO_ANY_EXIT, + TEXTDATA_TO_ANY_EXIT, XXXINIT_TO_SOME_INIT, XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, @@ -904,14 +903,9 @@ static const struct sectioncheck sectioncheck[] = { .mismatch = DATA_TO_ANY_INIT, }, { - .fromsec = { TEXT_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_EXIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, + .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_EXIT, + .mismatch = TEXTDATA_TO_ANY_EXIT, }, /* Do not reference init code/data from meminit code/data */ { @@ -1203,8 +1197,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, switch (mismatch->mismatch) { case TEXT_TO_ANY_INIT: case DATA_TO_ANY_INIT: - case TEXT_TO_ANY_EXIT: - case DATA_TO_ANY_EXIT: + case TEXTDATA_TO_ANY_EXIT: case XXXINIT_TO_SOME_INIT: case XXXEXIT_TO_SOME_EXIT: case ANY_INIT_TO_ANY_EXIT: -- cgit v1.2.3 From 1df380ff3018521bd1b129dff60984b61ade8cee Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 22 May 2023 01:04:23 +0900 Subject: modpost: remove *_sections[] arrays Use PATTERNS() macros to remove unneeded array definitions. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 36 +++++++++--------------------------- 1 file changed, 9 insertions(+), 27 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index cc4cf40a360f..7031e5da62e5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -838,24 +838,6 @@ static void check_section(const char *modname, struct elf_info *elf, #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ TEXT_SECTIONS, OTHER_TEXT_SECTIONS -/* init data sections */ -static const char *const init_data_sections[] = - { ALL_INIT_DATA_SECTIONS, NULL }; - -/* all init sections */ -static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; - -/* all text sections */ -static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; - -/* data section */ -static const char *const data_sections[] = { DATA_SECTIONS, NULL }; - -static const char *const head_sections[] = { ".head.text*", NULL }; -static const char *const linker_symbols[] = - { "__init_begin", "_sinittext", "_einittext", NULL }; -static const char *const optim_symbols[] = { "*.constprop.*", NULL }; - enum mismatch { TEXT_TO_ANY_INIT, DATA_TO_ANY_INIT, @@ -1028,14 +1010,14 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ - if (match(tosec, init_data_sections) && - match(fromsec, data_sections) && + if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) && + match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param")) return 0; /* Check for pattern 1a */ if (strcmp(tosec, ".init.text") == 0 && - match(fromsec, data_sections) && + match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param_ops_")) return 0; @@ -1058,18 +1040,18 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, return 0; /* Check for pattern 3 */ - if (match(fromsec, head_sections) && - match(tosec, init_sections)) + if (strstarts(fromsec, ".head.text") && + match(tosec, PATTERNS(ALL_INIT_SECTIONS))) return 0; /* Check for pattern 4 */ - if (match(tosym, linker_symbols)) + if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext"))) return 0; /* Check for pattern 5 */ - if (match(fromsec, text_sections) && - match(tosec, init_sections) && - match(fromsym, optim_symbols)) + if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) && + match(tosec, PATTERNS(ALL_INIT_SECTIONS)) && + match(fromsym, PATTERNS("*.constprop.*"))) return 0; return 1; -- cgit v1.2.3 From b7c63520f6703a25eebb4f8138fed764fcae1c6f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:55 +0900 Subject: modpost: fix section mismatch message for R_ARM_ABS32 addend_arm_rel() processes R_ARM_ABS32 in a wrong way. Here, test code. [test code 1] #include int __initdata foo; int get_foo(void) { return foo; } If you compile it with ARM versatile_defconfig, modpost will show the symbol name, (unknown). WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> (unknown) (section: .init.data) (You need to use GNU linker instead of LLD to reproduce it.) If you compile it for other architectures, modpost will show the correct symbol name. WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data) For R_ARM_ABS32, addend_arm_rel() sets r->r_addend to a wrong value. I just mimicked the code in arch/arm/kernel/module.c. However, there is more difficulty for ARM. Here, test code. [test code 2] #include int __initdata foo; int get_foo(void) { return foo; } int __initdata bar; int get_bar(void) { return bar; } With this commit applied, modpost will show the following messages for ARM versatile_defconfig: WARNING: modpost: vmlinux.o: section mismatch in reference: get_foo (section: .text) -> foo (section: .init.data) WARNING: modpost: vmlinux.o: section mismatch in reference: get_bar (section: .text) -> foo (section: .init.data) The reference from 'get_bar' to 'foo' seems wrong. I have no solution for this because it is true in assembly level. In the following output, relocation at 0x1c is no longer associated with 'bar'. The two relocation entries point to the same symbol, and the offset to 'bar' is encoded in the instruction 'r0, [r3, #4]'. Disassembly of section .text: 00000000 : 0: e59f3004 ldr r3, [pc, #4] @ c 4: e5930000 ldr r0, [r3] 8: e12fff1e bx lr c: 00000000 .word 0x00000000 00000010 : 10: e59f3004 ldr r3, [pc, #4] @ 1c 14: e5930004 ldr r0, [r3, #4] 18: e12fff1e bx lr 1c: 00000000 .word 0x00000000 Relocation section '.rel.text' at offset 0x244 contains 2 entries: Offset Info Type Sym.Value Sym. Name 0000000c 00000c02 R_ARM_ABS32 00000000 .init.data 0000001c 00000c02 R_ARM_ABS32 00000000 .init.data When find_elf_symbol() gets into a situation where relsym->st_name is zero, there is no guarantee to get the symbol name as written in C. I am keeping the current logic because it is useful in many architectures, but the symbol name is not always correct depending on the optimization. I left some comments in find_tosym(). Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 7031e5da62e5..c68dad45ace2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1094,6 +1094,10 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, if (relsym->st_name != 0) return relsym; + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ relsym_secindex = get_secindex(elf, relsym); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != relsym_secindex) @@ -1276,12 +1280,14 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); + Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); + void *loc = reloc_location(elf, sechdr, r); + uint32_t inst; switch (r_typ) { case R_ARM_ABS32: - /* From ARM ABI: (S + A) | T */ - r->r_addend = (int)(long) - (elf->symtab_start + ELF_R_SYM(r->r_info)); + inst = TO_NATIVE(*(uint32_t *)loc); + r->r_addend = inst + sym->st_value; break; case R_ARM_PC24: case R_ARM_CALL: -- cgit v1.2.3 From 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:56 +0900 Subject: modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24} addend_arm_rel() processes R_ARM_PC24, R_ARM_CALL, R_ARM_JUMP24 in a wrong way. Here, test code. [test code for R_ARM_JUMP24] .section .init.text,"ax" bar: bx lr .section .text,"ax" .globl foo foo: b bar [test code for R_ARM_CALL] .section .init.text,"ax" bar: bx lr .section .text,"ax" .globl foo foo: push {lr} bl bar pop {pc} If you compile it with ARM multi_v7_defconfig, modpost will show the symbol name, (unknown). WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text) (You need to use GNU linker instead of LLD to reproduce it.) Fix the code to make modpost show the correct symbol name. I imported (with adjustment) sign_extend32() from include/linux/bitops.h. The '+8' is the compensation for pc-relative instruction. It is documented in "ELF for the Arm Architecture" [1]. "If the relocation is pc-relative then compensation for the PC bias (the PC value is 8 bytes ahead of the executing instruction in Arm state and 4 bytes in Thumb state) must be encoded in the relocation by the object producer." [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Fixes: 56a974fa2d59 ("kbuild: make better section mismatch reports on arm") Fixes: 6e2e340b59d2 ("ARM: 7324/1: modpost: Fix section warnings for ARM for many compilers") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c68dad45ace2..e47bba7cfad2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1277,12 +1277,20 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_ARM_THM_JUMP19 51 #endif +static int32_t sign_extend32(int32_t value, int index) +{ + uint8_t shift = 31 - index; + + return (int32_t)(value << shift) >> shift; +} + static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); uint32_t inst; + int32_t offset; switch (r_typ) { case R_ARM_ABS32: @@ -1292,6 +1300,10 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: + inst = TO_NATIVE(*(uint32_t *)loc); + offset = sign_extend32((inst & 0x00ffffff) << 2, 25); + r->r_addend = offset + sym->st_value + 8; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: case R_ARM_THM_JUMP19: -- cgit v1.2.3 From 12ca2c67d742d390c0aa1f8c1cfc49469df55ddf Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:57 +0900 Subject: modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS} For ARM defconfig (i.e. multi_v7_defconfig), modpost fails to detect some types of section mismatches. [test code] #include int __initdata foo; int get_foo(void) { return foo; } It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.text' at offset 0x200 contains 2 entries: Offset Info Type Sym.Value Sym. Name 00000000 0000062b R_ARM_MOVW_ABS_NC 00000000 .LANCHOR0 00000004 0000062c R_ARM_MOVT_ABS 00000000 .LANCHOR0 Currently, R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS are just skipped. Add code to handle them. I checked arch/arm/kernel/module.c to learn how the offset is encoded in the instruction. The referenced symbol in relocation might be a local anchor. If is_valid_name() returns false, let's search for a better symbol name. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e47bba7cfad2..5a5e802b160c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1078,7 +1078,7 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) /** * Find symbol based on relocation record info. * In some cases the symbol supplied is a valid symbol so - * return refsym. If st_name != 0 we assume this is a valid symbol. + * return refsym. If is_valid_name() == true, we assume this is a valid symbol. * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ @@ -1091,7 +1091,7 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, Elf64_Sword d; unsigned int relsym_secindex; - if (relsym->st_name != 0) + if (is_valid_name(elf, relsym)) return relsym; /* @@ -1297,6 +1297,13 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) inst = TO_NATIVE(*(uint32_t *)loc); r->r_addend = inst + sym->st_value; break; + case R_ARM_MOVW_ABS_NC: + case R_ARM_MOVT_ABS: + inst = TO_NATIVE(*(uint32_t *)loc); + offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff), + 15); + r->r_addend = offset + sym->st_value; + break; case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: -- cgit v1.2.3 From b1a9651d48b42f3eddf095123c09f93e4df23060 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:58 +0900 Subject: modpost: refactor find_fromsym() and find_tosym() find_fromsym() and find_tosym() are similar - both of them iterate in the .symtab section and return the nearest symbol. The difference between them is that find_tosym() allows a negative distance, but the distance must be less than 20. Factor out the common part into find_nearest_sym(). Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 89 +++++++++++++++++++-------------------------------- 1 file changed, 33 insertions(+), 56 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 5a5e802b160c..32d56efe3f3b 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1075,79 +1075,56 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) return !is_mapping_symbol(name); } -/** - * Find symbol based on relocation record info. - * In some cases the symbol supplied is a valid symbol so - * return refsym. If is_valid_name() == true, we assume this is a valid symbol. - * In other cases the symbol needs to be looked up in the symbol table - * based on section and address. - * **/ -static Elf_Sym *find_tosym(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +/* Look up the nearest symbol based on the section and the address */ +static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf64_Sword distance = 20; - Elf64_Sword d; - unsigned int relsym_secindex; - - if (is_valid_name(elf, relsym)) - return relsym; + Elf_Addr distance; - /* - * Strive to find a better symbol name, but the resulting name may not - * match the symbol referenced in the original code. - */ - relsym_secindex = get_secindex(elf, relsym); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (get_secindex(elf, sym) != relsym_secindex) - continue; - if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) + if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; - if (sym->st_value == addr) - return sym; - /* Find a symbol nearby - addr are maybe negative */ - d = sym->st_value - addr; - if (d < 0) - d = addr - sym->st_value; - if (d < distance) { - distance = d; + + if (addr >= sym->st_value) + distance = addr - sym->st_value; + else if (allow_negative) + distance = sym->st_value - addr; + else + continue; + + if (distance <= min_distance) { + min_distance = distance; near = sym; } + + if (min_distance == 0) + break; } - /* We need a close match */ - if (distance < 20) - return near; - else - return NULL; + return near; } -/* - * Find symbols before or equal addr and after addr - in the section sec. - * If we find two symbols with equal offset prefer one with a valid name. - * The ELF format may have a better way to detect what type of symbol - * it is, but this works for now. - **/ static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, unsigned int secndx) { - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr distance = ~0; + return find_nearest_sym(elf, addr, secndx, false, ~0); +} - for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (get_secindex(elf, sym) != secndx) - continue; - if (!is_valid_name(elf, sym)) - continue; - if (sym->st_value <= addr && addr - sym->st_value <= distance) { - distance = addr - sym->st_value; - near = sym; - } - } - return near; +static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) +{ + /* If the supplied symbol has a valid name, return it */ + if (is_valid_name(elf, sym)) + return sym; + + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ + return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); } static bool is_executable_section(struct elf_info *elf, unsigned int secndx) -- cgit v1.2.3 From cd1824fb7a377882497e8b87a6f3a9ec19be3623 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:09:59 +0900 Subject: modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS} When CONFIG_THUMB2_KERNEL is enabled, modpost fails to detect some types of section mismatches. [test code] #include int __initdata foo; int get_foo(void) { return foo; } It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.text' at offset 0x1e8 contains 2 entries: Offset Info Type Sym.Value Sym. Name 00000000 0000052f R_ARM_THM_MOVW_AB 00000000 .LANCHOR0 00000004 00000530 R_ARM_THM_MOVT_AB 00000000 .LANCHOR0 Currently, R_ARM_THM_MOVW_ABS_NC and R_ARM_THM_MOVT_ABS are just skipped. Add code to handle them. I checked arch/arm/kernel/module.c to learn how the offset is encoded in the instruction. One more thing to note for Thumb instructions - the st_value is an odd value, so you need to mask the bit 0 to get the offset. Otherwise, you will get an off-by-one error in the nearest symbol look-up. It is documented in "ELF for the ARM Architecture" [1]: In addition to the normal rules for symbol values the following rules shall also apply to symbols of type STT_FUNC: * If the symbol addresses an Arm instruction, its value is the address of the instruction (in a relocatable object, the offset of the instruction from the start of the section containing it). * If the symbol addresses a Thumb instruction, its value is the address of the instruction with bit zero set (in a relocatable object, the section offset with bit zero set). * For the purposes of relocation the value used shall be the address of the instruction (st_value & ~1). [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 32d56efe3f3b..ec16f4d7e55a 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1082,7 +1082,8 @@ static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf_Addr distance; + Elf_Addr sym_addr, distance; + bool is_arm = (elf->hdr->e_machine == EM_ARM); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != secndx) @@ -1090,10 +1091,19 @@ static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, if (!is_valid_name(elf, sym)) continue; - if (addr >= sym->st_value) - distance = addr - sym->st_value; + sym_addr = sym->st_value; + + /* + * For ARM Thumb instruction, the bit 0 of st_value is set + * if the symbol is STT_FUNC type. Mask it to get the address. + */ + if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC) + sym_addr &= ~1; + + if (addr >= sym_addr) + distance = addr - sym_addr; else if (allow_negative) - distance = sym->st_value - addr; + distance = sym_addr - addr; else continue; @@ -1266,7 +1276,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); - uint32_t inst; + uint32_t inst, upper, lower; int32_t offset; switch (r_typ) { @@ -1288,6 +1298,17 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) offset = sign_extend32((inst & 0x00ffffff) << 2, 25); r->r_addend = offset + sym->st_value + 8; break; + case R_ARM_THM_MOVW_ABS_NC: + case R_ARM_THM_MOVT_ABS: + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + offset = sign_extend32(((upper & 0x000f) << 12) | + ((upper & 0x0400) << 1) | + ((lower & 0x7000) >> 4) | + (lower & 0x00ff), + 15); + r->r_addend = offset + sym->st_value; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: case R_ARM_THM_JUMP19: -- cgit v1.2.3 From 3310bae805250aec227eb056e8e61a246678f28a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:10:00 +0900 Subject: modpost: fix section_mismatch message for R_ARM_THM_{CALL,JUMP24,JUMP19} MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit addend_arm_rel() processes R_ARM_THM_CALL, R_ARM_THM_JUMP24, R_ARM_THM_JUMP19 in a wrong way. Here, test code. [test code for R_ARM_THM_JUMP24]   .section .init.text,"ax"   bar:           bx      lr   .section .text,"ax"   .globl foo   foo:           b       bar [test code for R_ARM_THM_CALL]   .section .init.text,"ax"   bar:           bx      lr   .section .text,"ax"   .globl foo   foo:           push    {lr}           bl      bar           pop     {pc} If you compile it with CONFIG_THUMB2_KERNEL=y, modpost will show the symbol name, (unknown).   WARNING: modpost: vmlinux.o: section mismatch in reference: foo (section: .text) -> (unknown) (section: .init.text) (You need to use GNU linker instead of LLD to reproduce it.) Fix the code to make modpost show the correct symbol name. I checked arch/arm/kernel/module.c to learn the encoding of R_ARM_THM_CALL and R_ARM_THM_JUMP24. The module does not support R_ARM_THM_JUMP19, but I checked its encoding in ARM ARM. The '+4' is the compensation for pc-relative instruction. It is documented in "ELF for the Arm Architecture" [1].   "If the relocation is pc-relative then compensation for the PC bias   (the PC value is 8 bytes ahead of the executing instruction in Arm   state and 4 bytes in Thumb state) must be encoded in the relocation   by the object producer." [1]: https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst Fixes: c9698e5cd6ad ("ARM: 7964/1: Detect section mismatches in thumb relocations") Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 53 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 47 insertions(+), 6 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ec16f4d7e55a..4e911ab711d4 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1276,7 +1276,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); void *loc = reloc_location(elf, sechdr, r); - uint32_t inst, upper, lower; + uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; switch (r_typ) { @@ -1309,13 +1309,54 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 15); r->r_addend = offset + sym->st_value; break; + case R_ARM_THM_JUMP19: + /* + * Encoding T3: + * S = upper[10] + * imm6 = upper[5:0] + * J1 = lower[13] + * J2 = lower[11] + * imm11 = lower[10:0] + * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0') + */ + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + + sign = (upper >> 10) & 1; + j1 = (lower >> 13) & 1; + j2 = (lower >> 11) & 1; + offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) | + ((upper & 0x03f) << 12) | + ((lower & 0x07ff) << 1), + 20); + r->r_addend = offset + sym->st_value + 4; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: - case R_ARM_THM_JUMP19: - /* From ARM ABI: ((S + A) | T) - P */ - r->r_addend = (int)(long)(elf->hdr + - sechdr->sh_offset + - (r->r_offset - sechdr->sh_addr)); + /* + * Encoding T4: + * S = upper[10] + * imm10 = upper[9:0] + * J1 = lower[13] + * J2 = lower[11] + * imm11 = lower[10:0] + * I1 = NOT(J1 XOR S) + * I2 = NOT(J2 XOR S) + * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0') + */ + upper = TO_NATIVE(*(uint16_t *)loc); + lower = TO_NATIVE(*((uint16_t *)loc + 1)); + + sign = (upper >> 10) & 1; + j1 = (lower >> 13) & 1; + j2 = (lower >> 11) & 1; + offset = sign_extend32((sign << 24) | + ((~(j1 ^ sign) & 1) << 23) | + ((~(j2 ^ sign) & 1) << 22) | + ((upper & 0x03ff) << 12) | + ((lower & 0x07ff) << 1), + 24); + r->r_addend = offset + sym->st_value + 4; break; default: return 1; -- cgit v1.2.3 From 2cb749466d179e3ccfe83eb8a52dc002d07b08af Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 1 Jun 2023 21:10:01 +0900 Subject: modpost: detect section mismatch for R_ARM_REL32 For ARM, modpost fails to detect some types of section mismatches. [test code] .section .init.data,"aw" bar: .long 0 .section .data,"aw" .globl foo foo: .long bar - . It is apparently a bad reference, but modpost does not report anything. The test code above produces the following relocations. Relocation section '.rel.data' at offset 0xe8 contains 1 entry: Offset Info Type Sym.Value Sym. Name 00000000 00000403 R_ARM_REL32 00000000 .init.data Currently, R_ARM_REL32 is just skipped. Handle it like R_ARM_ABS32. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 4e911ab711d4..d10f5bdcb753 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1281,6 +1281,7 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) switch (r_typ) { case R_ARM_ABS32: + case R_ARM_REL32: inst = TO_NATIVE(*(uint32_t *)loc); r->r_addend = inst + sym->st_value; break; -- cgit v1.2.3 From 20ff36856fe00879f82de71fe6f1482ca1b72334 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 6 Jun 2023 18:41:59 +0900 Subject: modpost: propagate W=1 build option to modpost "No build warning" is a strong requirement these days, so you must fix all issues before enabling a new warning flag. We often add a new warning to W=1 first so that the kbuild test robot blocks new breakages. This commit allows modpost to show extra warnings only when W=1 (or KBUILD_EXTRA_WARN=1) is given. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/Makefile.modpost | 1 + scripts/mod/modpost.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 0980c58d8afc..074e27c0c140 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -47,6 +47,7 @@ modpost-args = \ $(if $(KBUILD_MODPOST_WARN),-w) \ $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ + $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \ -o $@ modpost-deps := $(MODPOST) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d10f5bdcb753..3ea5eb2b1029 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -42,6 +42,8 @@ static bool allow_missing_ns_imports; static bool error_occurred; +static bool extra_warn; + /* * Cut off the warnings when there are too many. This typically occurs when * vmlinux is missing. ('make modules' without building vmlinux.) @@ -2199,7 +2201,7 @@ int main(int argc, char **argv) LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; - while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:o:aWwENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2224,6 +2226,9 @@ int main(int argc, char **argv) case 'T': files_source = optarg; break; + case 'W': + extra_warn = true; + break; case 'w': warn_unresolved = true; break; -- cgit v1.2.3 From 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 8 Jun 2023 11:23:40 +0300 Subject: modpost: fix off by one in is_executable_section() The > comparison should be >= to prevent an out of bounds array access. Fixes: 52dc0595d540 ("modpost: handle relocations mismatch in __ex_table.") Signed-off-by: Dan Carpenter Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3ea5eb2b1029..8decf04633bc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1141,7 +1141,7 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { - if (secndx > elf->num_sections) + if (secndx >= elf->num_sections) return false; return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0; -- cgit v1.2.3 From 94d6cb68124b7a63f24fcc345795ba5f9a27e694 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:51 +0900 Subject: modpost: pass struct module pointer to check_section_mismatch() The next commit will use it. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 8decf04633bc..403ba4d923f5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1211,7 +1211,7 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } -static void check_section_mismatch(const char *modname, struct elf_info *elf, +static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) @@ -1222,7 +1222,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, if (!mismatch) return; - default_mismatch_handler(modname, elf, mismatch, sym, + default_mismatch_handler(mod->name, elf, mismatch, sym, fsecndx, fromsec, faddr, tosec, taddr); } @@ -1406,7 +1406,7 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_LARCH_SUB32 55 #endif -static void section_rela(const char *modname, struct elf_info *elf, +static void section_rela(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { Elf_Rela *rela; @@ -1452,12 +1452,12 @@ static void section_rela(const char *modname, struct elf_info *elf, break; } - check_section_mismatch(modname, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } -static void section_rel(const char *modname, struct elf_info *elf, +static void section_rel(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { Elf_Rel *rel; @@ -1507,7 +1507,7 @@ static void section_rel(const char *modname, struct elf_info *elf, fatal("Please add code to calculate addend for this architecture\n"); } - check_section_mismatch(modname, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, elf->symtab_start + r_sym, fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1524,19 +1524,19 @@ static void section_rel(const char *modname, struct elf_info *elf, * to find all references to a section that reference a section that will * be discarded and warns about it. **/ -static void check_sec_ref(const char *modname, struct elf_info *elf) +static void check_sec_ref(struct module *mod, struct elf_info *elf) { int i; Elf_Shdr *sechdrs = elf->sechdrs; /* Walk through all sections */ for (i = 0; i < elf->num_sections; i++) { - check_section(modname, elf, &elf->sechdrs[i]); + check_section(mod->name, elf, &elf->sechdrs[i]); /* We want to process only relocation sections and not .init */ if (sechdrs[i].sh_type == SHT_RELA) - section_rela(modname, elf, &elf->sechdrs[i]); + section_rela(mod, elf, &elf->sechdrs[i]); else if (sechdrs[i].sh_type == SHT_REL) - section_rel(modname, elf, &elf->sechdrs[i]); + section_rel(mod, elf, &elf->sechdrs[i]); } } @@ -1707,7 +1707,7 @@ static void read_symbols(const char *modname) sym_get_data(&info, sym)); } - check_sec_ref(modname, &info); + check_sec_ref(mod, &info); if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); -- cgit v1.2.3 From b9f174c811e3ae4ae8959dc57e6adb9990e913f4 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Tue, 13 Jun 2023 14:14:56 -0700 Subject: x86/unwind/orc: Add ELF section with ORC version identifier Commits ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata") and fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two") changed the ORC format. Although ORC is internal to the kernel, it's the only way for external tools to get reliable kernel stack traces on x86-64. In particular, the drgn debugger [1] uses ORC for stack unwinding, and these format changes broke it [2]. As the drgn maintainer, I don't care how often or how much the kernel changes the ORC format as long as I have a way to detect the change. It suffices to store a version identifier in the vmlinux and kernel module ELF files (to use when parsing ORC sections from ELF), and in kernel memory (to use when parsing ORC from a core dump+symbol table). Rather than hard-coding a version number that needs to be manually bumped, Peterz suggested hashing the definitions from orc_types.h. If there is a format change that isn't caught by this, the hashing script can be updated. This patch adds an .orc_header allocated ELF section containing the 20-byte hash to vmlinux and kernel modules, along with the corresponding __start_orc_header and __stop_orc_header symbols in vmlinux. 1: https://github.com/osandov/drgn 2: https://github.com/osandov/drgn/issues/303 Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata") Fixes: fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two") Signed-off-by: Omar Sandoval Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com --- arch/x86/Makefile | 12 ++++++++++++ arch/x86/include/asm/Kbuild | 1 + arch/x86/include/asm/orc_header.h | 19 +++++++++++++++++++ arch/x86/kernel/unwind_orc.c | 3 +++ include/asm-generic/vmlinux.lds.h | 3 +++ scripts/mod/modpost.c | 5 +++++ scripts/orc_hash.sh | 16 ++++++++++++++++ 7 files changed, 59 insertions(+) create mode 100644 arch/x86/include/asm/orc_header.h create mode 100644 scripts/orc_hash.sh (limited to 'scripts/mod/modpost.c') diff --git a/arch/x86/Makefile b/arch/x86/Makefile index b39975977c03..fdc2e3abd615 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -305,6 +305,18 @@ ifeq ($(RETPOLINE_CFLAGS),) endif endif +ifdef CONFIG_UNWINDER_ORC +orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h +orc_hash_sh := $(srctree)/scripts/orc_hash.sh +targets += $(orc_hash_h) +quiet_cmd_orc_hash = GEN $@ + cmd_orc_hash = mkdir -p $(dir $@); \ + $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ +$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE + $(call if_changed,orc_hash) +archprepare: $(orc_hash_h) +endif + archclean: $(Q)rm -rf $(objtree)/arch/i386 $(Q)rm -rf $(objtree)/arch/x86_64 diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index 1e51650b79d7..4f1ce5fc4e19 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 +generated-y += orc_hash.h generated-y += syscalls_32.h generated-y += syscalls_64.h generated-y += syscalls_x32.h diff --git a/arch/x86/include/asm/orc_header.h b/arch/x86/include/asm/orc_header.h new file mode 100644 index 000000000000..07bacf3e160e --- /dev/null +++ b/arch/x86/include/asm/orc_header.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Copyright (c) Meta Platforms, Inc. and affiliates. */ + +#ifndef _ORC_HEADER_H +#define _ORC_HEADER_H + +#include +#include +#include + +/* + * The header is currently a 20-byte hash of the ORC entry definition; see + * scripts/orc_hash.sh. + */ +#define ORC_HEADER \ + __used __section(".orc_header") __aligned(4) \ + static const u8 orc_header[] = { ORC_HASH } + +#endif /* _ORC_HEADER_H */ diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index 3ac50b7298d1..4d8e518365f4 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -7,6 +7,9 @@ #include #include #include +#include + +ORC_HEADER; #define orc_warn(fmt, ...) \ printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index cebdf1ca415d..da9e5629ea43 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -839,6 +839,9 @@ #ifdef CONFIG_UNWINDER_ORC #define ORC_UNWIND_TABLE \ + .orc_header : AT(ADDR(.orc_header) - LOAD_OFFSET) { \ + BOUNDED_SECTION_BY(.orc_header, _orc_header) \ + } \ . = ALIGN(4); \ .orc_unwind_ip : AT(ADDR(.orc_unwind_ip) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.orc_unwind_ip, _orc_unwind_ip) \ diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d4531d09984d..c12150f96b88 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1979,6 +1979,11 @@ static void add_header(struct buffer *b, struct module *mod) buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "\n"); + buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n"); + buf_printf(b, "#include \n"); + buf_printf(b, "ORC_HEADER;\n"); + buf_printf(b, "#endif\n"); + buf_printf(b, "\n"); buf_printf(b, "BUILD_SALT;\n"); buf_printf(b, "BUILD_LTO_INFO;\n"); buf_printf(b, "\n"); diff --git a/scripts/orc_hash.sh b/scripts/orc_hash.sh new file mode 100644 index 000000000000..466611aa0053 --- /dev/null +++ b/scripts/orc_hash.sh @@ -0,0 +1,16 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-or-later +# Copyright (c) Meta Platforms, Inc. and affiliates. + +set -e + +printf '%s' '#define ORC_HASH ' + +awk ' +/^#define ORC_(REG|TYPE)_/ { print } +/^struct orc_entry {$/ { p=1 } +p { print } +/^}/ { p=0 }' | + sha1sum | + cut -d " " -f 1 | + sed 's/\([0-9a-f]\{2\}\)/0x\1,/g' -- cgit v1.2.3 From ddb5cdbafaaad6b99d7007ae1740403124502d03 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:52 +0900 Subject: kbuild: generate KSYMTAB entries by modpost Commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way whether the EXPORT_SYMBOL() is placed in *.c or *.S. For further cleanups, this commit applies a similar approach to the entire data structure of EXPORT_SYMBOL(). The EXPORT_SYMBOL() compilation is split into two stages. When a source file is compiled, EXPORT_SYMBOL() will be converted into a dummy symbol in the .export_symbol section. For example, EXPORT_SYMBOL(foo); EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE); will be encoded into the following assembly code: .section ".export_symbol","a" __export_symbol_foo: .asciz "" /* license */ .asciz "" /* name space */ .balign 8 .quad foo /* symbol reference */ .previous .section ".export_symbol","a" __export_symbol_bar: .asciz "GPL" /* license */ .asciz "BAR_NAMESPACE" /* name space */ .balign 8 .quad bar /* symbol reference */ .previous They are mere markers to tell modpost the name, license, and namespace of the symbols. They will be dropped from the final vmlinux and modules because the *(.export_symbol) will go into /DISCARD/ in the linker script. Then, modpost extracts all the information about EXPORT_SYMBOL() from the .export_symbol section, and generates the final C code: KSYMTAB_FUNC(foo, "", ""); KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE"); KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct kernel_symbol that will be linked to the vmlinux or a module. With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S files, providing the following benefits. [1] Deprecate EXPORT_DATA_SYMBOL() In the old days, EXPORT_SYMBOL() was only available in C files. To export a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file. arch/arm/kernel/armksyms.c is one example written in the classic manner. Commit 22823ab419d8 ("EXPORT_SYMBOL() for asm") removed this limitation. Since then, EXPORT_SYMBOL() can be placed close to the symbol definition in *.S files. It was a nice improvement. However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL() for data objects on some architectures. In the new approach, modpost checks symbol's type (STT_FUNC or not), and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly. There are only two users of EXPORT_DATA_SYMBOL: EXPORT_DATA_SYMBOL_GPL(empty_zero_page) (arch/ia64/kernel/head.S) EXPORT_DATA_SYMBOL(ia64_ivt) (arch/ia64/kernel/ivt.S) They are transformed as follows and output into .vmlinux.export.c KSYMTAB_DATA(empty_zero_page, "_gpl", ""); KSYMTAB_DATA(ia64_ivt, "", ""); The other EXPORT_SYMBOL users in ia64 assembly are output as KSYMTAB_FUNC(). EXPORT_DATA_SYMBOL() is now deprecated. [2] merge and There are two similar header implementations: include/linux/export.h for .c files include/asm-generic/export.h for .S files Ideally, the functionality should be consistent between them, but they tend to diverge. Commit 8651ec01daed ("module: add support for symbol namespaces.") did not support the namespace for *.S files. This commit shifts the essential implementation part to C, which supports EXPORT_SYMBOL_NS() for *.S files. and will remain as a wrapper of for a while. They will be removed after #include directives are all replaced with #include . [3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit) When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. We can do this better now; modpost can selectively emit KSYMTAB entries that are really used by modules. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- arch/ia64/include/asm/Kbuild | 1 + arch/ia64/include/asm/export.h | 3 -- include/asm-generic/export.h | 84 ++---------------------------- include/asm-generic/vmlinux.lds.h | 1 + include/linux/export-internal.h | 49 ++++++++++++++++++ include/linux/export.h | 101 +++++++++++++++--------------------- include/linux/pm.h | 4 +- kernel/module/internal.h | 12 +++++ scripts/Makefile.build | 8 ++- scripts/check-local-export | 4 +- scripts/mod/modpost.c | 106 ++++++++++++++++++++++++++------------ scripts/mod/modpost.h | 1 + 12 files changed, 190 insertions(+), 184 deletions(-) delete mode 100644 arch/ia64/include/asm/export.h (limited to 'scripts/mod/modpost.c') diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index aefae2efde9f..33733245f42b 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 generated-y += syscall_table.h generic-y += agp.h +generic-y += export.h generic-y += kvm_para.h generic-y += mcs_spinlock.h generic-y += vtime.h diff --git a/arch/ia64/include/asm/export.h b/arch/ia64/include/asm/export.h deleted file mode 100644 index ad18c6583252..000000000000 --- a/arch/ia64/include/asm/export.h +++ /dev/null @@ -1,3 +0,0 @@ -/* EXPORT_DATA_SYMBOL != EXPORT_SYMBOL here */ -#define KSYM_FUNC(name) @fptr(name) -#include diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 5e4b1f2369d2..0ae9f38a904c 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -3,86 +3,12 @@ #define __ASM_GENERIC_EXPORT_H /* - * This comment block is used by fixdep. Please do not remove. - * - * When CONFIG_MODVERSIONS is changed from n to y, all source files having - * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a - * side effect of the *.o build rule. + * and are deprecated. + * Please include directly. */ +#include -#ifndef KSYM_FUNC -#define KSYM_FUNC(x) x -#endif -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define KSYM_ALIGN 4 -#elif defined(CONFIG_64BIT) -#define KSYM_ALIGN 8 -#else -#define KSYM_ALIGN 4 -#endif - -.macro __put, val, name -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS - .long \val - ., \name - ., 0 -#elif defined(CONFIG_64BIT) - .quad \val, \name, 0 -#else - .long \val, \name, 0 -#endif -.endm - -/* - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ - -.macro ___EXPORT_SYMBOL name,val,sec -#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS) - .section ___ksymtab\sec+\name,"a" - .balign KSYM_ALIGN -__ksymtab_\name: - __put \val, __kstrtab_\name - .previous - .section __ksymtab_strings,"aMS",%progbits,1 -__kstrtab_\name: - .asciz "\name" - .previous -#endif -.endm - -#if defined(CONFIG_TRIM_UNUSED_KSYMS) - -#include -#include - -.macro __ksym_marker sym - .section ".discard.ksym","a" -__ksym_marker_\sym: - .previous -.endm - -#define __EXPORT_SYMBOL(sym, val, sec) \ - __ksym_marker sym; \ - __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym)) -#define __cond_export_sym(sym, val, sec, conf) \ - ___cond_export_sym(sym, val, sec, conf) -#define ___cond_export_sym(sym, val, sec, enabled) \ - __cond_export_sym_##enabled(sym, val, sec) -#define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#define __cond_export_sym_0(sym, val, sec) /* nothing */ - -#else -#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec -#endif - -#define EXPORT_SYMBOL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name),) -#define EXPORT_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, KSYM_FUNC(name), _gpl) -#define EXPORT_DATA_SYMBOL(name) \ - __EXPORT_SYMBOL(name, name,) -#define EXPORT_DATA_SYMBOL_GPL(name) \ - __EXPORT_SYMBOL(name, name,_gpl) +#define EXPORT_DATA_SYMBOL(name) EXPORT_SYMBOL(name) +#define EXPORT_DATA_SYMBOL_GPL(name) EXPORT_SYMBOL_GPL(name) #endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..e65d55e8819c 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -1006,6 +1006,7 @@ PATCHABLE_DISCARDS \ *(.discard) \ *(.discard.*) \ + *(.export_symbol) \ *(.modinfo) \ /* ld.bfd warns about .gnu.version* even when not emitted */ \ *(.gnu.version*) \ diff --git a/include/linux/export-internal.h b/include/linux/export-internal.h index fe7e6ba918f1..1c849db953a5 100644 --- a/include/linux/export-internal.h +++ b/include/linux/export-internal.h @@ -10,6 +10,55 @@ #include #include +#if defined(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS) +/* + * relative reference: this reduces the size by half on 64-bit architectures, + * and eliminates the need for absolute relocations that require runtime + * processing on relocatable kernels. + */ +#define __KSYM_REF(sym) ".long " #sym "- ." +#elif defined(CONFIG_64BIT) +#define __KSYM_REF(sym) ".quad " #sym +#else +#define __KSYM_REF(sym) ".long " #sym +#endif + +/* + * For every exported symbol, do the following: + * + * - Put the name of the symbol and namespace (empty string "" for none) in + * __ksymtab_strings. + * - Place a struct kernel_symbol entry in the __ksymtab section. + * + * Note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) + * section flag requires it. Use '%progbits' instead of '@progbits' since the + * former apparently works on all arches according to the binutils source. + */ +#define __KSYMTAB(name, sym, sec, ns) \ + asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1" "\n" \ + "__kstrtab_" #name ":" "\n" \ + " .asciz \"" #name "\"" "\n" \ + "__kstrtabns_" #name ":" "\n" \ + " .asciz \"" ns "\"" "\n" \ + " .previous" "\n" \ + " .section \"___ksymtab" sec "+" #name "\", \"a\"" "\n" \ + " .balign 4" "\n" \ + "__ksymtab_" #name ":" "\n" \ + __KSYM_REF(sym) "\n" \ + __KSYM_REF(__kstrtab_ ##name) "\n" \ + __KSYM_REF(__kstrtabns_ ##name) "\n" \ + " .previous" "\n" \ + ) + +#ifdef CONFIG_IA64 +#define KSYM_FUNC(name) @fptr(name) +#else +#define KSYM_FUNC(name) name +#endif + +#define KSYMTAB_FUNC(name, sec, ns) __KSYMTAB(name, KSYM_FUNC(name), sec, ns) +#define KSYMTAB_DATA(name, sec, ns) __KSYMTAB(name, name, sec, ns) + #define SYMBOL_CRC(sym, crc, sec) \ asm(".section \"___kcrctab" sec "+" #sym "\",\"a\"" "\n" \ "__crc_" #sym ":" "\n" \ diff --git a/include/linux/export.h b/include/linux/export.h index 3f31ced0d977..a01868136717 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -2,6 +2,8 @@ #ifndef _LINUX_EXPORT_H #define _LINUX_EXPORT_H +#include +#include #include /* @@ -28,72 +30,41 @@ extern struct module __this_module; #else #define THIS_MODULE ((struct module *)0) #endif +#endif /* __ASSEMBLY__ */ -#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#include -/* - * Emit the ksymtab entry as a pair of relative references: this reduces - * the size by half on 64-bit architectures, and eliminates the need for - * absolute relocations that require runtime processing on relocatable - * kernels. - */ -#define __KSYMTAB_ENTRY(sym, sec) \ - __ADDRESSABLE(sym) \ - asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \ - " .balign 4 \n" \ - "__ksymtab_" #sym ": \n" \ - " .long " #sym "- . \n" \ - " .long __kstrtab_" #sym "- . \n" \ - " .long __kstrtabns_" #sym "- . \n" \ - " .previous \n") - -struct kernel_symbol { - int value_offset; - int name_offset; - int namespace_offset; -}; +#ifdef CONFIG_64BIT +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 8 ASM_NL \ + .quad sym #else -#define __KSYMTAB_ENTRY(sym, sec) \ - static const struct kernel_symbol __ksymtab_##sym \ - __attribute__((section("___ksymtab" sec "+" #sym), used)) \ - __aligned(sizeof(void *)) \ - = { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym } - -struct kernel_symbol { - unsigned long value; - const char *name; - const char *namespace; -}; +#define __EXPORT_SYMBOL_REF(sym) \ + .balign 4 ASM_NL \ + .long sym #endif +#define ____EXPORT_SYMBOL(sym, license, ns) \ + .section ".export_symbol","a" ASM_NL \ + __export_symbol_##sym: ASM_NL \ + .asciz license ASM_NL \ + .asciz ns ASM_NL \ + __EXPORT_SYMBOL_REF(sym) ASM_NL \ + .previous + #ifdef __GENKSYMS__ #define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) +#elif defined(__ASSEMBLY__) + +#define ___EXPORT_SYMBOL(sym, license, ns) \ + ____EXPORT_SYMBOL(sym, license, ns) + #else -/* - * For every exported symbol, do the following: - * - * - Put the name of the symbol and namespace (empty string "" for none) in - * __ksymtab_strings. - * - Place a struct kernel_symbol entry in the __ksymtab section. - * - * note on .section use: we specify progbits since usage of the "M" (SHF_MERGE) - * section flag requires it. Use '%progbits' instead of '@progbits' since the - * former apparently works on all arches according to the binutils source. - */ -#define ___EXPORT_SYMBOL(sym, sec, ns) \ - extern typeof(sym) sym; \ - extern const char __kstrtab_##sym[]; \ - extern const char __kstrtabns_##sym[]; \ - asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ - "__kstrtab_" #sym ": \n" \ - " .asciz \"" #sym "\" \n" \ - "__kstrtabns_" #sym ": \n" \ - " .asciz \"" ns "\" \n" \ - " .previous \n"); \ - __KSYMTAB_ENTRY(sym, sec) +#define ___EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) #endif @@ -117,9 +88,21 @@ struct kernel_symbol { * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are * discarded in the final link stage. */ + +#ifdef __ASSEMBLY__ + +#define __ksym_marker(sym) \ + .section ".discard.ksym","a" ; \ +__ksym_marker_##sym: ; \ + .previous + +#else + #define __ksym_marker(sym) \ static int __ksym_marker_##sym[0] __section(".discard.ksym") __used +#endif + #define __EXPORT_SYMBOL(sym, sec, ns) \ __ksym_marker(sym); \ __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) @@ -148,10 +131,8 @@ struct kernel_symbol { #endif #define EXPORT_SYMBOL(sym) _EXPORT_SYMBOL(sym, "") -#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "_gpl") +#define EXPORT_SYMBOL_GPL(sym) _EXPORT_SYMBOL(sym, "GPL") #define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL(sym, "", __stringify(ns)) -#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "_gpl", __stringify(ns)) - -#endif /* !__ASSEMBLY__ */ +#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL(sym, "GPL", __stringify(ns)) #endif /* _LINUX_EXPORT_H */ diff --git a/include/linux/pm.h b/include/linux/pm.h index 035d9649eba4..f615193587d2 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -389,9 +389,9 @@ const struct dev_pm_ops name = { \ #endif #define EXPORT_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "", "") -#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "_gpl", "") +#define EXPORT_GPL_DEV_PM_OPS(name) _EXPORT_DEV_PM_OPS(name, "GPL", "") #define EXPORT_NS_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "", #ns) -#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "_gpl", #ns) +#define EXPORT_NS_GPL_DEV_PM_OPS(name, ns) _EXPORT_DEV_PM_OPS(name, "GPL", #ns) /* * Use this if you want to use the same suspend and resume callbacks for suspend diff --git a/kernel/module/internal.h b/kernel/module/internal.h index dc7b0160c480..c8b7b4dcf782 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -32,6 +32,18 @@ /* Maximum number of characters written by module_flags() */ #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) +struct kernel_symbol { +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS + int value_offset; + int name_offset; + int namespace_offset; +#else + unsigned long value; + const char *name; + const char *namespace; +#endif +}; + extern struct mutex module_mutex; extern struct list_head modules; diff --git a/scripts/Makefile.build b/scripts/Makefile.build index ddd644bd032d..4119e737fe87 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -163,7 +163,7 @@ quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ ifdef CONFIG_MODVERSIONS # When module versioning is enabled the following steps are executed: # o compile a .o from .c -# o if .o doesn't contain a __ksymtab version, i.e. does +# o if .o doesn't contain a __export_symbol_*, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old # genksyms on the preprocessed source and dump them into the .cmd file. @@ -171,7 +171,7 @@ ifdef CONFIG_MODVERSIONS # be compiled and linked to the kernel and/or modules. gen_symversions = \ - if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ + if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ >> $(dot-target).cmd; \ fi @@ -342,9 +342,7 @@ $(obj)/%.ll: $(src)/%.rs FORCE cmd_gensymtypes_S = \ { echo "\#include " ; \ echo "\#include " ; \ - $(CPP) $(a_flags) $< | \ - grep "\<___EXPORT_SYMBOL\>" | \ - sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \ + $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ diff --git a/scripts/check-local-export b/scripts/check-local-export index f90b5a9c67b3..86ad94647164 100755 --- a/scripts/check-local-export +++ b/scripts/check-local-export @@ -46,9 +46,9 @@ BEGIN { { symbol_types[$3]=$2 } # append the exported symbol to the array -($3 ~ /^__ksymtab_/) { +($3 ~ /^__export_symbol_.*/) { export_symbols[i] = $3 - sub(/^__ksymtab_/, "", export_symbols[i]) + sub(/^__export_symbol_/, "", export_symbols[i]) i++ } diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 403ba4d923f5..ce37e6de5df7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -217,6 +217,7 @@ struct symbol { unsigned int crc; bool crc_valid; bool weak; + bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ char name[]; }; @@ -533,6 +534,8 @@ static int parse_elf(struct elf_info *info, const char *filename) fatal("%s has NOBITS .modinfo\n", filename); info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; + } else if (!strcmp(secname, ".export_symbol")) { + info->export_symbol_secndx = i; } if (sechdrs[i].sh_type == SHT_SYMTAB) { @@ -655,18 +658,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info, ELF_ST_BIND(sym->st_info) == STB_WEAK); break; default: - /* All exported symbols */ - if (strstarts(symname, "__ksymtab_")) { - const char *name, *secname; - - name = symname + strlen("__ksymtab_"); - secname = sec_name(info, get_secindex(info, sym)); - - if (strstarts(secname, "___ksymtab_gpl+")) - sym_add_exported(name, mod, true); - else if (strstarts(secname, "___ksymtab+")) - sym_add_exported(name, mod, false); - } if (strcmp(symname, "init_module") == 0) mod->has_init = true; if (strcmp(symname, "cleanup_module") == 0) @@ -848,7 +839,6 @@ enum mismatch { XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, - EXPORT_TO_INIT_EXIT, EXTABLE_TO_NON_TEXT, }; @@ -920,12 +910,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, -/* Do not export init/exit functions or data */ -{ - .fromsec = { "___ksymtab*", NULL }, - .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, - .mismatch = EXPORT_TO_INIT_EXIT, -}, { .fromsec = { "__ex_table", NULL }, /* If you're adding any new black-listed sections in here, consider @@ -1180,10 +1164,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", modname, fromsym, fromsec, tosym, tosec); break; - case EXPORT_TO_INIT_EXIT: - warn("%s: EXPORT_SYMBOL used for init/exit symbol: %s (section: %s)\n", - modname, tosym, tosec); - break; case EXTABLE_TO_NON_TEXT: warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", modname, fromsec, (long)faddr, tosec, tosym); @@ -1211,14 +1191,75 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, } } +static void check_export_symbol(struct module *mod, struct elf_info *elf, + Elf_Addr faddr, const char *secname, + Elf_Sym *sym) +{ + static const char *prefix = "__export_symbol_"; + const char *label_name, *name, *data; + Elf_Sym *label; + struct symbol *s; + bool is_gpl; + + label = find_fromsym(elf, faddr, elf->export_symbol_secndx); + label_name = sym_name(elf, label); + + if (!strstarts(label_name, prefix)) { + error("%s: .export_symbol section contains strange symbol '%s'\n", + mod->name, label_name); + return; + } + + name = sym_name(elf, sym); + if (strcmp(label_name + strlen(prefix), name)) { + error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", + mod->name, name); + return; + } + + data = sym_get_data(elf, label); /* license */ + if (!strcmp(data, "GPL")) { + is_gpl = true; + } else if (!strcmp(data, "")) { + is_gpl = false; + } else { + error("%s: unknown license '%s' was specified for '%s'\n", + mod->name, data, name); + return; + } + + data += strlen(data) + 1; /* namespace */ + s = sym_add_exported(name, mod, is_gpl); + sym_update_namespace(name, data); + + /* + * We need to be aware whether we are exporting a function or + * a data on some architectures. + */ + s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC); + + if (match(secname, PATTERNS(INIT_SECTIONS))) + warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", + mod->name, name); + else if (match(secname, PATTERNS(EXIT_SECTIONS))) + warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", + mod->name, name); +} + static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); - const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); + const struct sectioncheck *mismatch; + + if (elf->export_symbol_secndx == fsecndx) { + check_export_symbol(mod, elf, faddr, tosec, sym); + return; + } + mismatch = section_mismatch(fromsec, tosec); if (!mismatch) return; @@ -1698,15 +1739,6 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } - for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - symname = remove_dot(info.strtab + sym->st_name); - - /* Apply symbol namespaces from __kstrtabns_ entries. */ - if (strstarts(symname, "__kstrtabns_")) - sym_update_namespace(symname + strlen("__kstrtabns_"), - sym_get_data(&info, sym)); - } - check_sec_ref(mod, &info); if (!mod->is_vmlinux) { @@ -1890,6 +1922,14 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; + /* generate struct for exported symbols */ + buf_printf(buf, "\n"); + list_for_each_entry(sym, &mod->exported_symbols, list) + buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", + sym->is_func ? "FUNC" : "DATA", sym->name, + sym->is_gpl_only ? "_gpl" : "", + sym->namespace ?: ""); + if (!modversions) return; diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index b1e2d95f8047..dfdb9484e325 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -137,6 +137,7 @@ struct elf_info { Elf_Shdr *sechdrs; Elf_Sym *symtab_start; Elf_Sym *symtab_stop; + unsigned int export_symbol_secndx; /* .export_symbol section */ char *strtab; char *modinfo; unsigned int modinfo_len; -- cgit v1.2.3 From 6d62b1c46b1e6e1686a0cf6617c96c80d4ab5cd5 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:54 +0900 Subject: modpost: check static EXPORT_SYMBOL* by modpost again Commit 31cb50b5590f ("kbuild: check static EXPORT_SYMBOL* by script instead of modpost") moved the static EXPORT_SYMBOL* check from the mostpost to a shell script because I thought it must be checked per compilation unit to avoid false negatives. I came up with an idea to do this in modpost, against combined ELF files. The relocation entries in ELF will find the correct exported symbol even if there exist symbols with the same name in different compilation units. Again, the same sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} Then, modpost can catch it correctly. MODPOST Module.symvers ERROR: modpost: vmlinux: local symbol 'foo' was exported Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/Makefile.build | 4 --- scripts/check-local-export | 70 ---------------------------------------------- scripts/mod/modpost.c | 7 +++++ 3 files changed, 7 insertions(+), 74 deletions(-) delete mode 100755 scripts/check-local-export (limited to 'scripts/mod/modpost.c') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 4119e737fe87..210142c3ff00 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -222,8 +222,6 @@ cmd_gen_ksymdeps = \ $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd endif -cmd_check_local_export = $(srctree)/scripts/check-local-export $@ - ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) endif @@ -231,7 +229,6 @@ endif define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) $(call cmd,gen_ksymdeps) - $(call cmd,check_local_export) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) @@ -243,7 +240,6 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) $(call cmd,gen_ksymdeps) - $(call cmd,check_local_export) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) $(call cmd,warn_shared_object) diff --git a/scripts/check-local-export b/scripts/check-local-export deleted file mode 100755 index 86ad94647164..000000000000 --- a/scripts/check-local-export +++ /dev/null @@ -1,70 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only -# -# Copyright (C) 2022 Masahiro Yamada -# Copyright (C) 2022 Owen Rafferty -# -# Exit with error if a local exported symbol is found. -# EXPORT_SYMBOL should be used for global symbols. - -set -e -pid=$$ - -# If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows -# 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by -# '2>/dev/null'. However, it suppresses real error messages as well. Add a -# hand-crafted error message here. -# -# TODO: -# Use --quiet instead of 2>/dev/null when we upgrade the minimum version of -# binutils to 2.37, llvm to 13.0.0. -# Then, the following line will be simpler: -# { ${NM} --quiet ${1} || kill 0; } | - -{ ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; kill $pid; } } | -${AWK} -v "file=${1}" ' -BEGIN { - i = 0 -} - -# Skip the line if the number of fields is less than 3. -# -# case 1) -# For undefined symbols, the first field (value) is empty. -# The outout looks like this: -# " U _printk" -# It is unneeded to record undefined symbols. -# -# case 2) -# For Clang LTO, llvm-nm outputs a line with type t but empty name: -# "---------------- t" -!length($3) { - next -} - -# save (name, type) in the associative array -{ symbol_types[$3]=$2 } - -# append the exported symbol to the array -($3 ~ /^__export_symbol_.*/) { - export_symbols[i] = $3 - sub(/^__export_symbol_/, "", export_symbols[i]) - i++ -} - -END { - exit_code = 0 - for (j = 0; j < i; ++j) { - name = export_symbols[j] - # nm(3) says "If lowercase, the symbol is usually local" - if (symbol_types[name] ~ /[a-z]/) { - printf "%s: error: local symbol %s was exported\n", - file, name | "cat 1>&2" - exit_code = 1 - } - } - - exit exit_code -}' - -exit $? diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ce37e6de5df7..6c1f95d18515 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1210,6 +1210,13 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, return; } + if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && + ELF_ST_BIND(sym->st_info) != STB_WEAK) { + error("%s: local symbol '%s' was exported\n", mod->name, + label_name + strlen(prefix)); + return; + } + name = sym_name(elf, sym); if (strcmp(label_name + strlen(prefix), name)) { error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", -- cgit v1.2.3 From 6e7611c485315a0e4e36c763d0810677e1f26ecd Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:55 +0900 Subject: modpost: squash sym_update_namespace() into sym_add_exported() Pass a set of the name, license, and namespace to sym_add_exported(). sym_update_namespace() is unneeded. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6c1f95d18515..bc9ef40ac620 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -355,26 +355,8 @@ static const char *sec_name(const struct elf_info *info, unsigned int secindex) #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) -static void sym_update_namespace(const char *symname, const char *namespace) -{ - struct symbol *s = find_symbol(symname); - - /* - * That symbol should have been created earlier and thus this is - * actually an assertion. - */ - if (!s) { - error("Could not update namespace(%s) for symbol %s\n", - namespace, symname); - return; - } - - free(s->namespace); - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; -} - static struct symbol *sym_add_exported(const char *name, struct module *mod, - bool gpl_only) + bool gpl_only, const char *namespace) { struct symbol *s = find_symbol(name); @@ -387,6 +369,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; + s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); @@ -1236,8 +1219,7 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, } data += strlen(data) + 1; /* namespace */ - s = sym_add_exported(name, mod, is_gpl); - sym_update_namespace(name, data); + s = sym_add_exported(name, mod, is_gpl, data); /* * We need to be aware whether we are exporting a function or @@ -2180,9 +2162,8 @@ static void read_dump(const char *fname) mod = new_module(modname, strlen(modname)); mod->from_dump = true; } - s = sym_add_exported(symname, mod, gpl_only); + s = sym_add_exported(symname, mod, gpl_only, namespace); sym_set_crc(s, crc); - sym_update_namespace(symname, namespace); } free(buf); return; -- cgit v1.2.3 From 700c48b439921b67715e25380e0f67e6e490d7b8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:56 +0900 Subject: modpost: use null string instead of NULL pointer for default namespace The default namespace is the null string, "". When set, the null string "" is converted to NULL: s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; When printed, the NULL pointer is get back to the null string: sym->namespace ?: "" This saves 1 byte memory allocated for "", but loses the readability. In kernel-space, we strive to save memory, but modpost is a userspace tool used to build the kernel. On modern systems, such small piece of memory is not a big deal. Handle the namespace string as is. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bc9ef40ac620..a7c979b0ea21 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -300,6 +300,13 @@ static bool contains_namespace(struct list_head *head, const char *namespace) { struct namespace_list *list; + /* + * The default namespace is null string "", which is always implicitly + * contained. + */ + if (!namespace[0]) + return true; + list_for_each_entry(list, head, list) { if (!strcmp(list->namespace, namespace)) return true; @@ -369,7 +376,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; + s->namespace = NOFAIL(strdup(namespace)); list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); @@ -1829,8 +1836,7 @@ static void check_exports(struct module *mod) else basename = mod->name; - if (exp->namespace && - !contains_namespace(&mod->imported_namespaces, exp->namespace)) { + if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) { modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR, "module %s uses symbol %s from namespace %s, but does not import it.\n", basename, exp->name, exp->namespace); @@ -1916,8 +1922,7 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) list_for_each_entry(sym, &mod->exported_symbols, list) buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, - sym->is_gpl_only ? "_gpl" : "", - sym->namespace ?: ""); + sym->is_gpl_only ? "_gpl" : "", sym->namespace); if (!modversions) return; @@ -2185,7 +2190,7 @@ static void write_dump(const char *fname) buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", - sym->namespace ?: ""); + sym->namespace); } } write_buf(&buf, fname); -- cgit v1.2.3 From 5e9e95cc9148b82074a5eae283e63bce3f1aacfe Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:57 +0900 Subject: kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada --- .gitignore | 2 -- Makefile | 22 ++------------ include/linux/export.h | 67 +++++++---------------------------------- scripts/Makefile.build | 15 +--------- scripts/Makefile.modpost | 7 +++++ scripts/adjust_autoksyms.sh | 73 --------------------------------------------- scripts/basic/fixdep.c | 3 +- scripts/gen_autoksyms.sh | 62 -------------------------------------- scripts/gen_ksymdeps.sh | 30 ------------------- scripts/mod/modpost.c | 57 +++++++++++++++++++++++++++++++---- scripts/remove-stale-files | 4 +++ 11 files changed, 78 insertions(+), 264 deletions(-) delete mode 100755 scripts/adjust_autoksyms.sh delete mode 100755 scripts/gen_autoksyms.sh delete mode 100755 scripts/gen_ksymdeps.sh (limited to 'scripts/mod/modpost.c') diff --git a/.gitignore b/.gitignore index 7f86e0837909..c3ce78ca20d2 100644 --- a/.gitignore +++ b/.gitignore @@ -51,7 +51,6 @@ *.symversions *.tab.[ch] *.tar -*.usyms *.xz *.zst Module.symvers @@ -112,7 +111,6 @@ modules.order # /include/config/ /include/generated/ -/include/ksym/ /arch/*/include/generated/ # stgit generated dirs diff --git a/Makefile b/Makefile index f836936fb4d8..cc3fe09c4dec 100644 --- a/Makefile +++ b/Makefile @@ -1193,28 +1193,12 @@ endif export KBUILD_VMLINUX_LIBS export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds -# Recurse until adjust_autoksyms.sh is satisfied -PHONY += autoksyms_recursive ifdef CONFIG_TRIM_UNUSED_KSYMS # For the kernel to actually contain only the needed exported symbols, # we have to build modules as well to determine what those symbols are. -# (this can be evaluated only once include/config/auto.conf has been included) KBUILD_MODULES := 1 - -autoksyms_recursive: $(build-dir) modules.order - $(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \ - "$(MAKE) -f $(srctree)/Makefile autoksyms_recursive" endif -autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h) - -quiet_cmd_autoksyms_h = GEN $@ - cmd_autoksyms_h = mkdir -p $(dir $@); \ - $(CONFIG_SHELL) $(srctree)/scripts/gen_autoksyms.sh $@ - -$(autoksyms_h): - $(call cmd,autoksyms_h) - # '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14 quiet_cmd_ar_vmlinux.a = AR $@ cmd_ar_vmlinux.a = \ @@ -1223,7 +1207,7 @@ quiet_cmd_ar_vmlinux.a = AR $@ $(AR) mPiT $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt) targets += vmlinux.a -vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt autoksyms_recursive FORCE +vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE $(call if_changed,ar_vmlinux.a) PHONY += vmlinux_o @@ -1279,7 +1263,7 @@ scripts: scripts_basic scripts_dtc PHONY += prepare archprepare archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \ - asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h \ + asm-generic $(version_h) include/generated/utsrelease.h \ include/generated/compile.h include/generated/autoconf.h remove-stale-files prepare0: archprepare @@ -2039,7 +2023,7 @@ clean: $(clean-dirs) -o -name '*.dtb.S' -o -name '*.dtbo.S' \ -o -name '*.dt.yaml' \ -o -name '*.dwo' -o -name '*.lst' \ - -o -name '*.su' -o -name '*.mod' -o -name '*.usyms' \ + -o -name '*.su' -o -name '*.mod' \ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \ -o -name '*.lex.c' -o -name '*.tab.[ch]' \ -o -name '*.asn1.[ch]' \ diff --git a/include/linux/export.h b/include/linux/export.h index a01868136717..1de600734071 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -42,7 +42,7 @@ extern struct module __this_module; .long sym #endif -#define ____EXPORT_SYMBOL(sym, license, ns) \ +#define ___EXPORT_SYMBOL(sym, license, ns) \ .section ".export_symbol","a" ASM_NL \ __export_symbol_##sym: ASM_NL \ .asciz license ASM_NL \ @@ -50,24 +50,6 @@ extern struct module __this_module; __EXPORT_SYMBOL_REF(sym) ASM_NL \ .previous -#ifdef __GENKSYMS__ - -#define ___EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) - -#elif defined(__ASSEMBLY__) - -#define ___EXPORT_SYMBOL(sym, license, ns) \ - ____EXPORT_SYMBOL(sym, license, ns) - -#else - -#define ___EXPORT_SYMBOL(sym, license, ns) \ - extern typeof(sym) sym; \ - __ADDRESSABLE(sym) \ - asm(__stringify(____EXPORT_SYMBOL(sym, license, ns))) - -#endif - #if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS) /* @@ -77,50 +59,21 @@ extern struct module __this_module; */ #define __EXPORT_SYMBOL(sym, sec, ns) -#elif defined(CONFIG_TRIM_UNUSED_KSYMS) +#elif defined(__GENKSYMS__) -#include +#define __EXPORT_SYMBOL(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) -/* - * For fine grained build dependencies, we want to tell the build system - * about each possible exported symbol even if they're not actually exported. - * We use a symbol pattern __ksym_marker_ that the build system filters - * from the $(NM) output (see scripts/gen_ksymdeps.sh). These symbols are - * discarded in the final link stage. - */ - -#ifdef __ASSEMBLY__ - -#define __ksym_marker(sym) \ - .section ".discard.ksym","a" ; \ -__ksym_marker_##sym: ; \ - .previous - -#else - -#define __ksym_marker(sym) \ - static int __ksym_marker_##sym[0] __section(".discard.ksym") __used - -#endif +#elif defined(__ASSEMBLY__) -#define __EXPORT_SYMBOL(sym, sec, ns) \ - __ksym_marker(sym); \ - __cond_export_sym(sym, sec, ns, __is_defined(__KSYM_##sym)) -#define __cond_export_sym(sym, sec, ns, conf) \ - ___cond_export_sym(sym, sec, ns, conf) -#define ___cond_export_sym(sym, sec, ns, enabled) \ - __cond_export_sym_##enabled(sym, sec, ns) -#define __cond_export_sym_1(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) - -#ifdef __GENKSYMS__ -#define __cond_export_sym_0(sym, sec, ns) __GENKSYMS_EXPORT_SYMBOL(sym) -#else -#define __cond_export_sym_0(sym, sec, ns) /* nothing */ -#endif +#define __EXPORT_SYMBOL(sym, license, ns) \ + ___EXPORT_SYMBOL(sym, license, ns) #else -#define __EXPORT_SYMBOL(sym, sec, ns) ___EXPORT_SYMBOL(sym, sec, ns) +#define __EXPORT_SYMBOL(sym, license, ns) \ + extern typeof(sym) sym; \ + __ADDRESSABLE(sym) \ + asm(__stringify(___EXPORT_SYMBOL(sym, license, ns))) #endif /* CONFIG_MODULES */ diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 210142c3ff00..4735b958097a 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -82,7 +82,7 @@ ifdef need-builtin targets-for-builtin += $(obj)/built-in.a endif -targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ +targets-for-modules := $(foreach x, o mod, \ $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) ifdef need-modorder @@ -217,18 +217,12 @@ is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetar $(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) -ifdef CONFIG_TRIM_UNUSED_KSYMS -cmd_gen_ksymdeps = \ - $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd -endif - ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) endif define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) - $(call cmd,gen_ksymdeps) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) @@ -239,7 +233,6 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) - $(call cmd,gen_ksymdeps) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) $(call cmd,warn_shared_object) @@ -258,12 +251,6 @@ cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \ $(obj)/%.mod: FORCE $(call if_changed,mod) -# List module undefined symbols -cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ - -$(obj)/%.usyms: $(obj)/%.o FORCE - $(call if_changed,undefined_syms) - quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \ diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 074e27c0c140..39472e834b63 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -91,6 +91,13 @@ targets += .vmlinux.objs .vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE $(call if_changed,vmlinux_objs) +ifdef CONFIG_TRIM_UNUSED_KSYMS +ksym-wl := $(CONFIG_UNUSED_KSYMS_WHITELIST) +ksym-wl := $(if $(filter-out /%, $(ksym-wl)),$(srctree)/)$(ksym-wl) +modpost-args += -t $(addprefix -u , $(ksym-wl)) +modpost-deps += $(ksym-wl) +endif + ifeq ($(wildcard vmlinux.o),) missing-input := vmlinux.o output-symdump := modules-only.symvers diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh deleted file mode 100755 index f1b5ac818411..000000000000 --- a/scripts/adjust_autoksyms.sh +++ /dev/null @@ -1,73 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only - -# Script to update include/generated/autoksyms.h and dependency files -# -# Copyright: (C) 2016 Linaro Limited -# Created by: Nicolas Pitre, January 2016 -# - -# Update the include/generated/autoksyms.h file. -# -# For each symbol being added or removed, the corresponding dependency -# file's timestamp is updated to force a rebuild of the affected source -# file. All arguments passed to this script are assumed to be a command -# to be exec'd to trigger a rebuild of those files. - -set -e - -cur_ksyms_file="include/generated/autoksyms.h" -new_ksyms_file="include/generated/autoksyms.h.tmpnew" - -info() { - if [ "$quiet" != "silent_" ]; then - printf " %-7s %s\n" "$1" "$2" - fi -} - -info "CHK" "$cur_ksyms_file" - -# Use "make V=1" to debug this script. -case "$KBUILD_VERBOSE" in -*1*) - set -x - ;; -esac - -# Generate a new symbol list file -$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh --modorder "$new_ksyms_file" - -# Extract changes between old and new list and touch corresponding -# dependency files. -changed=$( -count=0 -sort "$cur_ksyms_file" "$new_ksyms_file" | uniq -u | -sed -n 's/^#define __KSYM_\(.*\) 1/\1/p' | -while read sympath; do - if [ -z "$sympath" ]; then continue; fi - depfile="include/ksym/${sympath}" - mkdir -p "$(dirname "$depfile")" - touch "$depfile" - # Filesystems with coarse time precision may create timestamps - # equal to the one from a file that was very recently built and that - # needs to be rebuild. Let's guard against that by making sure our - # dep files are always newer than the first file we created here. - while [ ! "$depfile" -nt "$new_ksyms_file" ]; do - touch "$depfile" - done - echo $((count += 1)) -done | tail -1 ) -changed=${changed:-0} - -if [ $changed -gt 0 ]; then - # Replace the old list with tne new one - old=$(grep -c "^#define __KSYM_" "$cur_ksyms_file" || true) - new=$(grep -c "^#define __KSYM_" "$new_ksyms_file" || true) - info "KSYMS" "symbols: before=$old, after=$new, changed=$changed" - info "UPD" "$cur_ksyms_file" - mv -f "$new_ksyms_file" "$cur_ksyms_file" - # Then trigger a rebuild of affected source files - exec $@ -else - rm -f "$new_ksyms_file" -fi diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c index fa562806c2be..84b6efa849f4 100644 --- a/scripts/basic/fixdep.c +++ b/scripts/basic/fixdep.c @@ -246,8 +246,7 @@ static void *read_file(const char *filename) /* Ignore certain dependencies */ static int is_ignored_file(const char *s, int len) { - return str_ends_with(s, len, "include/generated/autoconf.h") || - str_ends_with(s, len, "include/generated/autoksyms.h"); + return str_ends_with(s, len, "include/generated/autoconf.h"); } /* Do not parse these files */ diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh deleted file mode 100755 index 12bcfae940ee..000000000000 --- a/scripts/gen_autoksyms.sh +++ /dev/null @@ -1,62 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0-only - -# Create an autoksyms.h header file from the list of all module's needed symbols -# as recorded in *.usyms files and the user-provided symbol whitelist. - -set -e - -# Use "make V=1" to debug this script. -case "$KBUILD_VERBOSE" in -*1*) - set -x - ;; -esac - -read_modorder= - -if [ "$1" = --modorder ]; then - shift - read_modorder=1 -fi - -output_file="$1" - -needed_symbols= - -# Special case for modversions (see modpost.c) -if grep -q "^CONFIG_MODVERSIONS=y$" include/config/auto.conf; then - needed_symbols="$needed_symbols module_layout" -fi - -ksym_wl=$(sed -n 's/^CONFIG_UNUSED_KSYMS_WHITELIST=\(.*\)$/\1/p' include/config/auto.conf) -if [ -n "$ksym_wl" ]; then - [ "${ksym_wl}" != "${ksym_wl#/}" ] || ksym_wl="$abs_srctree/$ksym_wl" - if [ ! -f "$ksym_wl" ] || [ ! -r "$ksym_wl" ]; then - echo "ERROR: '$ksym_wl' whitelist file not found" >&2 - exit 1 - fi -fi - -# Generate a new ksym list file with symbols needed by the current -# set of modules. -cat > "$output_file" << EOT -/* - * Automatically generated file; DO NOT EDIT. - */ - -EOT - -{ - [ -n "${read_modorder}" ] && sed 's/o$/usyms/' modules.order | xargs cat - echo "$needed_symbols" - [ -n "$ksym_wl" ] && cat "$ksym_wl" -} | sed -e 's/ /\n/g' | sed -n -e '/^$/!p' | -# Remove the dot prefix for ppc64; symbol names with a dot (.) hold entry -# point addresses. -sed -e 's/^\.//' | -sort -u | -# Ignore __this_module. It's not an exported symbol, and will be resolved -# when the final .ko's are linked. -grep -v '^__this_module$' | -sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file" diff --git a/scripts/gen_ksymdeps.sh b/scripts/gen_ksymdeps.sh deleted file mode 100755 index 8ee533f33659..000000000000 --- a/scripts/gen_ksymdeps.sh +++ /dev/null @@ -1,30 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0 - -set -e - -# List of exported symbols -# -# If the object has no symbol, $NM warns 'no symbols'. -# Suppress the stderr. -# TODO: -# Use -q instead of 2>/dev/null when we upgrade the minimum version of -# binutils to 2.37, llvm to 13.0.0. -ksyms=$($NM $1 2>/dev/null | sed -n 's/.*__ksym_marker_\(.*\)/\1/p') - -if [ -z "$ksyms" ]; then - exit 0 -fi - -echo -echo "ksymdeps_$1 := \\" - -for s in $ksyms -do - printf ' $(wildcard include/ksym/%s) \\\n' "$s" -done - -echo -echo "$1: \$(ksymdeps_$1)" -echo -echo "\$(ksymdeps_$1):" diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index a7c979b0ea21..3d9f3e2b2a2d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -35,6 +35,9 @@ static bool warn_unresolved; static int sec_mismatch_count; static bool sec_mismatch_warn_only = true; +/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */ +static bool trim_unused_exports; + /* ignore missing files */ static bool ignore_missing_files; /* If set to 1, only warn (instead of error) about missing ns imports */ @@ -219,6 +222,7 @@ struct symbol { bool weak; bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ + bool used; /* there exists a user of this symbol */ char name[]; }; @@ -1826,6 +1830,7 @@ static void check_exports(struct module *mod) continue; } + exp->used = true; s->module = exp->module; s->crc_valid = exp->crc_valid; s->crc = exp->crc; @@ -1849,6 +1854,23 @@ static void check_exports(struct module *mod) } } +static void handle_white_list_exports(const char *white_list) +{ + char *buf, *p, *name; + + buf = read_text_file(white_list); + p = buf; + + while ((name = strsep(&p, "\n"))) { + struct symbol *sym = find_symbol(name); + + if (sym) + sym->used = true; + } + + free(buf); +} + static void check_modname_len(struct module *mod) { const char *mod_name; @@ -1919,10 +1941,14 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) /* generate struct for exported symbols */ buf_printf(buf, "\n"); - list_for_each_entry(sym, &mod->exported_symbols, list) + list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, sym->is_gpl_only ? "_gpl" : "", sym->namespace); + } if (!modversions) return; @@ -1930,6 +1956,9 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) /* record CRCs for exported symbols */ buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + if (!sym->crc_valid) warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" "Is \"%s\" prototyped in ?\n", @@ -2093,9 +2122,6 @@ static void write_mod_c_file(struct module *mod) char fname[PATH_MAX]; int ret; - check_modname_len(mod); - check_exports(mod); - add_header(&buf, mod); add_exported_symbols(&buf, mod); add_versions(&buf, mod); @@ -2187,6 +2213,9 @@ static void write_dump(const char *fname) if (mod->from_dump) continue; list_for_each_entry(sym, &mod->exported_symbols, list) { + if (trim_unused_exports && !sym->used) + continue; + buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", @@ -2229,12 +2258,13 @@ int main(int argc, char **argv) { struct module *mod; char *missing_namespace_deps = NULL; + char *unused_exports_white_list = NULL; char *dump_write = NULL, *files_source = NULL; int opt; LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; - while ((opt = getopt(argc, argv, "ei:mnT:o:aWwENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:to:au:WwENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2259,6 +2289,12 @@ int main(int argc, char **argv) case 'T': files_source = optarg; break; + case 't': + trim_unused_exports = true; + break; + case 'u': + unused_exports_white_list = optarg; + break; case 'W': extra_warn = true; break; @@ -2291,6 +2327,17 @@ int main(int argc, char **argv) if (files_source) read_symbols_from_files(files_source); + list_for_each_entry(mod, &modules, list) { + if (mod->from_dump || mod->is_vmlinux) + continue; + + check_modname_len(mod); + check_exports(mod); + } + + if (unused_exports_white_list) + handle_white_list_exports(unused_exports_white_list); + list_for_each_entry(mod, &modules, list) { if (mod->from_dump) continue; diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files index 7f432900671a..f3659ea0335b 100755 --- a/scripts/remove-stale-files +++ b/scripts/remove-stale-files @@ -33,3 +33,7 @@ rm -f rust/target.json rm -f scripts/bin2c rm -f .scmversion + +rm -rf include/ksym + +find . -name '*.usyms' | xargs rm -f -- cgit v1.2.3 From 78dac1a22944910ba5c1475c384309d30c99afaa Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:58 +0900 Subject: modpost: merge two similar section mismatch warnings In case of section mismatch, modpost shows slightly different messages. For extable section mismatch: "%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n" For the other cases: "%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n" They are similar. Merge them. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3d9f3e2b2a2d..c7faa455f978 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1147,21 +1147,10 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, sec_mismatch_count++; - switch (mismatch->mismatch) { - case TEXT_TO_ANY_INIT: - case DATA_TO_ANY_INIT: - case TEXTDATA_TO_ANY_EXIT: - case XXXINIT_TO_SOME_INIT: - case XXXEXIT_TO_SOME_EXIT: - case ANY_INIT_TO_ANY_EXIT: - case ANY_EXIT_TO_ANY_INIT: - warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", - modname, fromsym, fromsec, tosym, tosec); - break; - case EXTABLE_TO_NON_TEXT: - warn("%s(%s+0x%lx): Section mismatch in reference to the %s:%s\n", - modname, fromsec, (long)faddr, tosec, tosym); + warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", + modname, fromsym, fromsec, tosym, tosec); + if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) { if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" "section \"%s\" which is black-listed.\n" @@ -1181,7 +1170,6 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, else error("%s+0x%lx references non-executable section '%s'\n", fromsec, (long)faddr, tosec); - break; } } -- cgit v1.2.3 From f234627898d7644998e28938390fa3d63efeefb7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 12 Jun 2023 00:50:59 +0900 Subject: modpost: show offset from symbol for section mismatch warnings Currently, modpost only shows the symbol names and section names, so it repeats the same message if there are multiple relocations in the same symbol. It is common the relocation spans across multiple instructions. It is better to show the offset from the symbol. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c7faa455f978..39cf43d61d51 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1147,8 +1147,8 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf, sec_mismatch_count++; - warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", - modname, fromsym, fromsec, tosym, tosec); + warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n", + modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec); if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) { if (match(tosec, mismatch->bad_tosec)) -- cgit v1.2.3 From 1fffe7a34c89b12b58f88b280bc10ce034477c3a Mon Sep 17 00:00:00 2001 From: Vincenzo Palazzo Date: Fri, 16 Jun 2023 01:40:37 +0200 Subject: script: modpost: emit a warning when the description is missing Emit a warning when the mod description is missed and only when the W=1 is enabled. Reported-by: Roland Kletzing Link: https://bugzilla.kernel.org/show_bug.cgi?id=10770 Signed-off-by: Vincenzo Palazzo Tested-by: Nicolas Schier Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 39cf43d61d51..983f507a47ad 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1720,6 +1720,8 @@ static void read_symbols(const char *modname) } } + if (extra_warn && !get_modinfo(&info, "description")) + warn("missing MODULE_DESCRIPTION() in %s\n", modname); for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = remove_dot(info.strtab + sym->st_name); -- cgit v1.2.3 From b31db651f745604371e4d3304f5b16fc3d9d0110 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:19 +0900 Subject: modpost: factor out inst location calculation to section_rel() All the addend_*_rel() functions calculate the instruction location in the same way. Factor out the similar code to the caller. Squash reloc_location() too. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 983f507a47ad..40fdc1a69483 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1256,16 +1256,9 @@ static void check_section_mismatch(struct module *mod, struct elf_info *elf, tosec, taddr); } -static unsigned int *reloc_location(struct elf_info *elf, - Elf_Shdr *sechdr, Elf_Rela *r) -{ - return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset); -} - -static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_386_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); switch (r_typ) { case R_386_32: @@ -1302,11 +1295,10 @@ static int32_t sign_extend32(int32_t value, int index) return (int32_t)(value << shift) >> shift; } -static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_arm_rel(void *loc, struct elf_info *elf, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); - void *loc = reloc_location(elf, sechdr, r); uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; @@ -1396,11 +1388,10 @@ static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) return 0; } -static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_mips_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); - unsigned int inst; + uint32_t inst; if (r_typ == R_MIPS_HI16) return 1; /* skip this */ @@ -1502,6 +1493,8 @@ static void section_rel(struct module *mod, struct elf_info *elf, return; for (rel = start; rel < stop; rel++) { + void *loc; + r.r_offset = TO_NATIVE(rel->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (elf->hdr->e_machine == EM_MIPS) { @@ -1519,17 +1512,20 @@ static void section_rel(struct module *mod, struct elf_info *elf, r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = 0; + + loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); + switch (elf->hdr->e_machine) { case EM_386: - if (addend_386_rel(elf, sechdr, &r)) + if (addend_386_rel(loc, &r)) continue; break; case EM_ARM: - if (addend_arm_rel(elf, sechdr, &r)) + if (addend_arm_rel(loc, elf, &r)) continue; break; case EM_MIPS: - if (addend_mips_rel(elf, sechdr, &r)) + if (addend_mips_rel(loc, &r)) continue; break; default: -- cgit v1.2.3 From 8aa00e2c3da470c82148f64b6a3cac2d79bb9d16 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:20 +0900 Subject: modpost: factor out Elf_Sym pointer calculation to section_rel() Pass the Elf_Sym pointer to addend_arm_rel() as well as to check_section_mismatch(). Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 40fdc1a69483..bfe26b835db2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1295,10 +1295,9 @@ static int32_t sign_extend32(int32_t value, int index) return (int32_t)(value << shift) >> shift; } -static int addend_arm_rel(void *loc, struct elf_info *elf, Elf_Rela *r) +static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - Elf_Sym *sym = elf->symtab_start + ELF_R_SYM(r->r_info); uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; @@ -1493,6 +1492,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, return; for (rel = start; rel < stop; rel++) { + Elf_Sym *tsym; void *loc; r.r_offset = TO_NATIVE(rel->r_offset); @@ -1514,6 +1514,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, r.r_addend = 0; loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); + tsym = elf->symtab_start + ELF_R_SYM(r.r_info); switch (elf->hdr->e_machine) { case EM_386: @@ -1521,7 +1522,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, continue; break; case EM_ARM: - if (addend_arm_rel(loc, elf, &r)) + if (addend_arm_rel(loc, tsym, &r)) continue; break; case EM_MIPS: @@ -1532,7 +1533,7 @@ static void section_rel(struct module *mod, struct elf_info *elf, fatal("Please add code to calculate addend for this architecture\n"); } - check_section_mismatch(mod, elf, elf->symtab_start + r_sym, + check_section_mismatch(mod, elf, tsym, fsecndx, fromsec, r.r_offset, r.r_addend); } } -- cgit v1.2.3 From 8e86ebefdd5ca15458fcb3a03da89ab9cad6382b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 20 Jun 2023 21:05:21 +0900 Subject: modpost: continue even with unknown relocation type Currently, unknown relocation types are just skipped. The value of r_addend is only needed to get the symbol name in case is_valid_name(elf, sym) returns false. Even if we do not know how to calculate r_addend, we should continue. At worst, we will get "(unknown)" as the symbol name, but it is better than failing to detect section mismatches. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bfe26b835db2..73f4f5588b67 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1267,6 +1267,8 @@ static int addend_386_rel(uint32_t *location, Elf_Rela *r) case R_386_PC32: r->r_addend = TO_NATIVE(*location) + 4; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1382,7 +1384,7 @@ static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r) r->r_addend = offset + sym->st_value + 4; break; default: - return 1; + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1392,8 +1394,6 @@ static int addend_mips_rel(uint32_t *location, Elf_Rela *r) unsigned int r_typ = ELF_R_TYPE(r->r_info); uint32_t inst; - if (r_typ == R_MIPS_HI16) - return 1; /* skip this */ inst = TO_NATIVE(*location); switch (r_typ) { case R_MIPS_LO16: @@ -1405,6 +1405,8 @@ static int addend_mips_rel(uint32_t *location, Elf_Rela *r) case R_MIPS_32: r->r_addend = inst; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1514,20 +1516,17 @@ static void section_rel(struct module *mod, struct elf_info *elf, r.r_addend = 0; loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); - tsym = elf->symtab_start + ELF_R_SYM(r.r_info); + tsym = elf->symtab_start + r_sym; switch (elf->hdr->e_machine) { case EM_386: - if (addend_386_rel(loc, &r)) - continue; + addend_386_rel(loc, &r); break; case EM_ARM: - if (addend_arm_rel(loc, tsym, &r)) - continue; + addend_arm_rel(loc, tsym, &r); break; case EM_MIPS: - if (addend_mips_rel(loc, &r)) - continue; + addend_mips_rel(loc, &r); break; default: fatal("Please add code to calculate addend for this architecture\n"); -- cgit v1.2.3 From f5983dab0ead92dc2690d147f0604a0badcac6a8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 28 Jun 2023 01:32:05 +0900 Subject: modpost: define more R_ARM_* for old distributions On CentOS 7, the following build error occurs. scripts/mod/modpost.c: In function 'addend_arm_rel': scripts/mod/modpost.c:1312:7: error: 'R_ARM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_MOVW_ABS_NC: ^~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1312:7: note: each undeclared identifier is reported only once for each function it appears in scripts/mod/modpost.c:1313:7: error: 'R_ARM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_MOVT_ABS: ^~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1326:7: error: 'R_ARM_THM_MOVW_ABS_NC' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_THM_MOVW_ABS_NC: ^~~~~~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 scripts/mod/modpost.c:1327:7: error: 'R_ARM_THM_MOVT_ABS' undeclared (first use in this function); did you mean 'R_ARM_THM_ABS5'? case R_ARM_THM_MOVT_ABS: ^~~~~~~~~~~~~~~~~~ R_ARM_THM_ABS5 Fixes: 12ca2c67d742 ("modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS}") Fixes: cd1824fb7a37 ("modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS}") Reported-by: Tetsuo Handa Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'scripts/mod/modpost.c') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 73f4f5588b67..603a4f9587a4 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1286,6 +1286,23 @@ static int addend_386_rel(uint32_t *location, Elf_Rela *r) #ifndef R_ARM_THM_JUMP24 #define R_ARM_THM_JUMP24 30 #endif + +#ifndef R_ARM_MOVW_ABS_NC +#define R_ARM_MOVW_ABS_NC 43 +#endif + +#ifndef R_ARM_MOVT_ABS +#define R_ARM_MOVT_ABS 44 +#endif + +#ifndef R_ARM_THM_MOVW_ABS_NC +#define R_ARM_THM_MOVW_ABS_NC 47 +#endif + +#ifndef R_ARM_THM_MOVT_ABS +#define R_ARM_THM_MOVT_ABS 48 +#endif + #ifndef R_ARM_THM_JUMP19 #define R_ARM_THM_JUMP19 51 #endif -- cgit v1.2.3