diff options
Diffstat (limited to 'tools/objtool/check.c')
| -rw-r--r-- | tools/objtool/check.c | 463 |
1 files changed, 254 insertions, 209 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ca5b74603008..190b2f6e360a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -5,6 +5,7 @@ #include <string.h> #include <stdlib.h> +#include <inttypes.h> #include <sys/mman.h> #include <arch/elf.h> @@ -263,7 +264,8 @@ static void init_cfi_state(struct cfi_state *cfi) cfi->drap_offset = -1; } -static void init_insn_state(struct insn_state *state, struct section *sec) +static void init_insn_state(struct objtool_file *file, struct insn_state *state, + struct section *sec) { memset(state, 0, sizeof(*state)); init_cfi_state(&state->cfi); @@ -273,7 +275,7 @@ static void init_insn_state(struct insn_state *state, struct section *sec) * not correctly determine insn->call_dest->sec (external symbols do * not have a section). */ - if (vmlinux && noinstr && sec) + if (opts.link && opts.noinstr && sec) state->noinstr = sec->noinstr; } @@ -339,7 +341,7 @@ static void *cfi_hash_alloc(unsigned long size) if (cfi_hash == (void *)-1L) { WARN("mmap fail cfi_hash"); cfi_hash = NULL; - } else if (stats) { + } else if (opts.stats) { printf("cfi_bits: %d\n", cfi_bits); } @@ -434,7 +436,7 @@ static int decode_instructions(struct objtool_file *file) } } - if (stats) + if (opts.stats) printf("nr_insns: %lu\n", nr_insns); return 0; @@ -497,7 +499,7 @@ static int init_pv_ops(struct objtool_file *file) struct symbol *sym; int idx, nr; - if (!noinstr) + if (!opts.noinstr) return 0; file->pv_ops = NULL; @@ -560,12 +562,12 @@ static int add_dead_ends(struct objtool_file *file) else if (reloc->addend == reloc->sym->sec->sh.sh_size) { insn = find_last_insn(file, reloc->sym->sec); if (!insn) { - WARN("can't find unreachable insn at %s+0x%lx", + WARN("can't find unreachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } } else { - WARN("can't find unreachable insn at %s+0x%lx", + WARN("can't find unreachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } @@ -595,12 +597,12 @@ reachable: else if (reloc->addend == reloc->sym->sec->sh.sh_size) { insn = find_last_insn(file, reloc->sym->sec); if (!insn) { - WARN("can't find reachable insn at %s+0x%lx", + WARN("can't find reachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } } else { - WARN("can't find reachable insn at %s+0x%lx", + WARN("can't find reachable insn at %s+0x%" PRIx64, reloc->sym->sec->name, reloc->addend); return -1; } @@ -668,7 +670,7 @@ static int create_static_call_sections(struct objtool_file *file) key_sym = find_symbol_by_name(file->elf, tmp); if (!key_sym) { - if (!module) { + if (!opts.module) { WARN("static_call: can't find static_call_key symbol: %s", tmp); return -1; } @@ -761,7 +763,7 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file) list_for_each_entry(insn, &file->endbr_list, call_node) idx++; - if (stats) { + if (opts.stats) { printf("ibt: ENDBR at function start: %d\n", file->nr_endbr); printf("ibt: ENDBR inside functions: %d\n", file->nr_endbr_int); printf("ibt: superfluous ENDBR: %d\n", idx); @@ -1028,7 +1030,7 @@ static void add_uaccess_safe(struct objtool_file *file) struct symbol *func; const char **name; - if (!uaccess) + if (!opts.uaccess) return; for (name = uaccess_safe_builtin; *name; name++) { @@ -1144,7 +1146,7 @@ static void annotate_call_site(struct objtool_file *file, * attribute so they need a little help, NOP out any such calls from * noinstr text. */ - if (insn->sec->noinstr && sym->profiling_func) { + if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) { if (reloc) { reloc->type = R_NONE; elf_write_reloc(file->elf, reloc); @@ -1170,7 +1172,7 @@ static void annotate_call_site(struct objtool_file *file, return; } - if (mcount && sym->fentry) { + if (opts.mcount && sym->fentry) { if (sibling) WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); @@ -1256,7 +1258,7 @@ static bool is_first_func_insn(struct objtool_file *file, struct instruction *in if (insn->offset == insn->func->offset) return true; - if (ibt) { + if (opts.ibt) { struct instruction *prev = prev_insn_same_sym(file, insn); if (prev && prev->type == INSN_ENDBR && @@ -1592,7 +1594,7 @@ static int handle_jump_alt(struct objtool_file *file, return -1; } - if (special_alt->key_addend & 2) { + if (opts.hack_jump_label && special_alt->key_addend & 2) { struct reloc *reloc = insn_reloc(file, orig_insn); if (reloc) { @@ -1699,7 +1701,7 @@ static int add_special_section_alts(struct objtool_file *file) free(special_alt); } - if (stats) { + if (opts.stats) { printf("jl\\\tNOP\tJMP\n"); printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short); printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long); @@ -1945,7 +1947,7 @@ static int read_unwind_hints(struct objtool_file *file) insn->hint = true; - if (ibt && hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) { + if (opts.ibt && hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) { struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset); if (sym && sym->bind == STB_GLOBAL && @@ -2806,7 +2808,7 @@ static int update_cfi_state(struct instruction *insn, } /* detect when asm code uses rbp as a scratch register */ - if (!no_fp && insn->func && op->src.reg == CFI_BP && + if (opts.stackval && insn->func && op->src.reg == CFI_BP && cfa->base != CFI_BP) cfi->bp_scratch = true; break; @@ -3182,114 +3184,6 @@ static struct instruction *next_insn_to_validate(struct objtool_file *file, return next_insn_same_sec(file, insn); } -static struct instruction * -validate_ibt_reloc(struct objtool_file *file, struct reloc *reloc) -{ - struct instruction *dest; - struct section *sec; - unsigned long off; - - sec = reloc->sym->sec; - off = reloc->sym->offset; - - if ((reloc->sec->base->sh.sh_flags & SHF_EXECINSTR) && - (reloc->type == R_X86_64_PC32 || reloc->type == R_X86_64_PLT32)) - off += arch_dest_reloc_offset(reloc->addend); - else - off += reloc->addend; - - dest = find_insn(file, sec, off); - if (!dest) - return NULL; - - if (dest->type == INSN_ENDBR) { - if (!list_empty(&dest->call_node)) - list_del_init(&dest->call_node); - - return NULL; - } - - if (reloc->sym->static_call_tramp) - return NULL; - - return dest; -} - -static void warn_noendbr(const char *msg, struct section *sec, unsigned long offset, - struct instruction *dest) -{ - WARN_FUNC("%srelocation to !ENDBR: %s", sec, offset, msg, - offstr(dest->sec, dest->offset)); -} - -static void validate_ibt_dest(struct objtool_file *file, struct instruction *insn, - struct instruction *dest) -{ - if (dest->func && dest->func == insn->func) { - /* - * Anything from->to self is either _THIS_IP_ or IRET-to-self. - * - * There is no sane way to annotate _THIS_IP_ since the compiler treats the - * relocation as a constant and is happy to fold in offsets, skewing any - * annotation we do, leading to vast amounts of false-positives. - * - * There's also compiler generated _THIS_IP_ through KCOV and - * such which we have no hope of annotating. - * - * As such, blanket accept self-references without issue. - */ - return; - } - - if (dest->noendbr) - return; - - warn_noendbr("", insn->sec, insn->offset, dest); -} - -static void validate_ibt_insn(struct objtool_file *file, struct instruction *insn) -{ - struct instruction *dest; - struct reloc *reloc; - - switch (insn->type) { - case INSN_CALL: - case INSN_CALL_DYNAMIC: - case INSN_JUMP_CONDITIONAL: - case INSN_JUMP_UNCONDITIONAL: - case INSN_JUMP_DYNAMIC: - case INSN_JUMP_DYNAMIC_CONDITIONAL: - case INSN_RETURN: - /* - * We're looking for code references setting up indirect code - * flow. As such, ignore direct code flow and the actual - * dynamic branches. - */ - return; - - case INSN_NOP: - /* - * handle_group_alt() will create INSN_NOP instruction that - * don't belong to any section, ignore all NOP since they won't - * carry a (useful) relocation anyway. - */ - return; - - default: - break; - } - - for (reloc = insn_reloc(file, insn); - reloc; - reloc = find_reloc_by_dest_range(file->elf, insn->sec, - reloc->offset + 1, - (insn->offset + insn->len) - (reloc->offset + 1))) { - dest = validate_ibt_reloc(file, reloc); - if (dest) - validate_ibt_dest(file, insn, dest); - } -} - /* * Follow the branch starting at the given instruction, and recursively follow * any other branches (jumps). Meanwhile, track the frame pointer state at @@ -3363,7 +3257,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, ret = validate_branch(file, func, alt->insn, state); if (ret) { - if (backtrace) + if (opts.backtrace) BT_FUNC("(alt)", insn); return ret; } @@ -3379,11 +3273,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, switch (insn->type) { case INSN_RETURN: - if (sls && !insn->retpoline_safe && - next_insn && next_insn->type != INSN_TRAP) { - WARN_FUNC("missing int3 after ret", - insn->sec, insn->offset); - } return validate_return(func, insn, &state); case INSN_CALL: @@ -3392,7 +3281,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, if (ret) return ret; - if (!no_fp && func && !is_fentry_call(insn) && + if (opts.stackval && func && !is_fentry_call(insn) && !has_valid_stack_frame(&state)) { WARN_FUNC("call without frame pointer save/setup", sec, insn->offset); @@ -3415,7 +3304,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, ret = validate_branch(file, func, insn->jump_dest, state); if (ret) { - if (backtrace) + if (opts.backtrace) BT_FUNC("(branch)", insn); return ret; } @@ -3427,13 +3316,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, break; case INSN_JUMP_DYNAMIC: - if (sls && !insn->retpoline_safe && - next_insn && next_insn->type != INSN_TRAP) { - WARN_FUNC("missing int3 after indirect jump", - insn->sec, insn->offset); - } - - /* fallthrough */ case INSN_JUMP_DYNAMIC_CONDITIONAL: if (is_sibling_call(insn)) { ret = validate_sibling_call(file, insn, &state); @@ -3499,9 +3381,6 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, break; } - if (ibt) - validate_ibt_insn(file, insn); - if (insn->dead_end) return 0; @@ -3528,7 +3407,7 @@ static int validate_unwind_hints(struct objtool_file *file, struct section *sec) if (!file->hints) return 0; - init_insn_state(&state, sec); + init_insn_state(file, &state, sec); if (sec) { insn = find_insn(file, sec, 0); @@ -3541,7 +3420,7 @@ static int validate_unwind_hints(struct objtool_file *file, struct section *sec) while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) { if (insn->hint && !insn->visited && !insn->ignore) { ret = validate_branch(file, insn->func, insn, state); - if (ret && backtrace) + if (ret && opts.backtrace) BT_FUNC("<=== (hint)", insn); warnings += ret; } @@ -3571,7 +3450,7 @@ static int validate_retpoline(struct objtool_file *file) * loaded late, they very much do need retpoline in their * .init.text */ - if (!strcmp(insn->sec->name, ".init.text") && !module) + if (!strcmp(insn->sec->name, ".init.text") && !opts.module) continue; WARN_FUNC("indirect %s found in RETPOLINE build", @@ -3614,14 +3493,14 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio return true; /* - * Whole archive runs might encounder dead code from weak symbols. + * Whole archive runs might encounter dead code from weak symbols. * This is where the linker will have dropped the weak symbol in * favour of a regular symbol, but leaves the code in place. * * In this case we'll find a piece of code (whole function) that is not * covered by a !section symbol. Ignore them. */ - if (!insn->func && lto) { + if (opts.link && !insn->func) { int size = find_symbol_hole_containing(insn->sec, insn->offset); unsigned long end = insn->offset + size; @@ -3728,7 +3607,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec, state->uaccess = sym->uaccess_safe; ret = validate_branch(file, insn->func, insn, *state); - if (ret && backtrace) + if (ret && opts.backtrace) BT_FUNC("<=== (sym)", insn); return ret; } @@ -3743,7 +3622,7 @@ static int validate_section(struct objtool_file *file, struct section *sec) if (func->type != STT_FUNC) continue; - init_insn_state(&state, sec); + init_insn_state(file, &state, sec); set_func_state(&state.cfi); warnings += validate_symbol(file, sec, func, &state); @@ -3752,7 +3631,7 @@ static int validate_section(struct objtool_file *file, struct section *sec) return warnings; } -static int validate_vmlinux_functions(struct objtool_file *file) +static int validate_noinstr_sections(struct objtool_file *file) { struct section *sec; int warnings = 0; @@ -3787,48 +3666,208 @@ static int validate_functions(struct objtool_file *file) return warnings; } +static void mark_endbr_used(struct instruction *insn) +{ + if (!list_empty(&insn->call_node)) + list_del_init(&insn->call_node); +} + +static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn) +{ + struct instruction *dest; + struct reloc *reloc; + unsigned long off; + int warnings = 0; + + /* + * Looking for function pointer load relocations. Ignore + * direct/indirect branches: + */ + switch (insn->type) { + case INSN_CALL: + case INSN_CALL_DYNAMIC: + case INSN_JUMP_CONDITIONAL: + case INSN_JUMP_UNCONDITIONAL: + case INSN_JUMP_DYNAMIC: + case INSN_JUMP_DYNAMIC_CONDITIONAL: + case INSN_RETURN: + case INSN_NOP: + return 0; + default: + break; + } + + for (reloc = insn_reloc(file, insn); + reloc; + reloc = find_reloc_by_dest_range(file->elf, insn->sec, + reloc->offset + 1, + (insn->offset + insn->len) - (reloc->offset + 1))) { + + /* + * static_call_update() references the trampoline, which + * doesn't have (or need) ENDBR. Skip warning in that case. + */ + if (reloc->sym->static_call_tramp) + continue; + + off = reloc->sym->offset; + if (reloc->type == R_X86_64_PC32 || reloc->type == R_X86_64_PLT32) + off += arch_dest_reloc_offset(reloc->addend); + else + off += reloc->addend; + + dest = find_insn(file, reloc->sym->sec, off); + if (!dest) + continue; + + if (dest->type == INSN_ENDBR) { + mark_endbr_used(dest); + continue; + } + + if (dest->func && dest->func == insn->func) { + /* + * Anything from->to self is either _THIS_IP_ or + * IRET-to-self. + * + * There is no sane way to annotate _THIS_IP_ since the + * compiler treats the relocation as a constant and is + * happy to fold in offsets, skewing any annotation we + * do, leading to vast amounts of false-positives. + * + * There's also compiler generated _THIS_IP_ through + * KCOV and such which we have no hope of annotating. + * + * As such, blanket accept self-references without + * issue. + */ + continue; + } + + if (dest->noendbr) + continue; + + WARN_FUNC("relocation to !ENDBR: %s", + insn->sec, insn->offset, + offstr(dest->sec, dest->offset)); + + warnings++; + } + + return warnings; +} + +static int validate_ibt_data_reloc(struct objtool_file *file, + struct reloc *reloc) +{ + struct instruction *dest; + + dest = find_insn(file, reloc->sym->sec, + reloc->sym->offset + reloc->addend); + if (!dest) + return 0; + + if (dest->type == INSN_ENDBR) { + mark_endbr_used(dest); + return 0; + } + + if (dest->noendbr) + return 0; + + WARN_FUNC("data relocation to !ENDBR: %s", + reloc->sec->base, reloc->offset, + offstr(dest->sec, dest->offset)); + + return 1; +} + +/* + * Validate IBT rules and remove used ENDBR instructions from the seal list. + * Unused ENDBR instructions will be annotated for sealing (i.e., replaced with + * NOPs) later, in create_ibt_endbr_seal_sections(). + */ static int validate_ibt(struct objtool_file *file) { struct section *sec; struct reloc *reloc; + struct instruction *insn; + int warnings = 0; + + for_each_insn(file, insn) + warnings += validate_ibt_insn(file, insn); for_each_sec(file, sec) { - bool is_data; - /* already done in validate_branch() */ + /* Already done by validate_ibt_insn() */ if (sec->sh.sh_flags & SHF_EXECINSTR) continue; if (!sec->reloc) continue; - if (!strncmp(sec->name, ".orc", 4)) + /* + * These sections can reference text addresses, but not with + * the intent to indirect branch to them. + */ + if (!strncmp(sec->name, ".discard", 8) || + !strncmp(sec->name, ".debug", 6) || + !strcmp(sec->name, ".altinstructions") || + !strcmp(sec->name, ".ibt_endbr_seal") || + !strcmp(sec->name, ".orc_unwind_ip") || + !strcmp(sec->name, ".parainstructions") || + !strcmp(sec->name, ".retpoline_sites") || + !strcmp(sec->name, ".smp_locks") || + !strcmp(sec->name, ".static_call_sites") || + !strcmp(sec->name, "_error_injection_whitelist") || + !strcmp(sec->name, "_kprobe_blacklist") || + !strcmp(sec->name, "__bug_table") || + !strcmp(sec->name, "__ex_table") || + !strcmp(sec->name, "__jump_table") || + !strcmp(sec->name, "__mcount_loc") || + !strcmp(sec->name, "__tracepoints")) continue; - if (!strncmp(sec->name, ".discard", 8)) - continue; + list_for_each_entry(reloc, &sec->reloc->reloc_list, list) + warnings += validate_ibt_data_reloc(file, reloc); + } - if (!strncmp(sec->name, ".debug", 6)) - continue; + return warnings; +} - if (!strcmp(sec->name, "_error_injection_whitelist")) - continue; +static int validate_sls(struct objtool_file *file) +{ + struct instruction *insn, *next_insn; + int warnings = 0; - if (!strcmp(sec->name, "_kprobe_blacklist")) - continue; + for_each_insn(file, insn) { + next_insn = next_insn_same_sec(file, insn); - is_data = strstr(sec->name, ".data") || strstr(sec->name, ".rodata"); + if (insn->retpoline_safe) + continue; - list_for_each_entry(reloc, &sec->reloc->reloc_list, list) { - struct instruction *dest; + switch (insn->type) { + case INSN_RETURN: + if (!next_insn || next_insn->type != INSN_TRAP) { + WARN_FUNC("missing int3 after ret", + insn->sec, insn->offset); + warnings++; + } - dest = validate_ibt_reloc(file, reloc); - if (is_data && dest && !dest->noendbr) - warn_noendbr("data ", sec, reloc->offset, dest); + break; + case INSN_JUMP_DYNAMIC: + if (!next_insn || next_insn->type != INSN_TRAP) { + WARN_FUNC("missing int3 after indirect jump", + insn->sec, insn->offset); + warnings++; + } + break; + default: + break; } } - return 0; + return warnings; } static int validate_reachable_instructions(struct objtool_file *file) @@ -3853,16 +3892,6 @@ int check(struct objtool_file *file) { int ret, warnings = 0; - if (lto && !(vmlinux || module)) { - fprintf(stderr, "--lto requires: --vmlinux or --module\n"); - return 1; - } - - if (ibt && !lto) { - fprintf(stderr, "--ibt requires: --lto\n"); - return 1; - } - arch_initial_func_cfi_state(&initial_func_cfi); init_cfi_state(&init_cfi); init_cfi_state(&func_cfi); @@ -3883,73 +3912,89 @@ int check(struct objtool_file *file) if (list_empty(&file->insn_list)) goto out; - if (vmlinux && !lto) { - ret = validate_vmlinux_functions(file); + if (opts.retpoline) { + ret = validate_retpoline(file); if (ret < 0) - goto out; - + return ret; warnings += ret; - goto out; } - if (retpoline) { - ret = validate_retpoline(file); + if (opts.stackval || opts.orc || opts.uaccess) { + ret = validate_functions(file); if (ret < 0) - return ret; + goto out; warnings += ret; - } - ret = validate_functions(file); - if (ret < 0) - goto out; - warnings += ret; + ret = validate_unwind_hints(file, NULL); + if (ret < 0) + goto out; + warnings += ret; - ret = validate_unwind_hints(file, NULL); - if (ret < 0) - goto out; - warnings += ret; + if (!warnings) { + ret = validate_reachable_instructions(file); + if (ret < 0) + goto out; + warnings += ret; + } - if (ibt) { + } else if (opts.noinstr) { + ret = validate_noinstr_sections(file); + if (ret < 0) + goto out; + warnings += ret; + } + + if (opts.ibt) { ret = validate_ibt(file); if (ret < 0) goto out; warnings += ret; } - if (!warnings) { - ret = validate_reachable_instructions(file); + if (opts.sls) { + ret = validate_sls(file); if (ret < 0) goto out; warnings += ret; } - ret = create_static_call_sections(file); - if (ret < 0) - goto out; - warnings += ret; + if (opts.static_call) { + ret = create_static_call_sections(file); + if (ret < 0) + goto out; + warnings += ret; + } - if (retpoline) { + if (opts.retpoline) { ret = create_retpoline_sites_sections(file); if (ret < 0) goto out; warnings += ret; } - if (mcount) { + if (opts.mcount) { ret = create_mcount_loc_sections(file); if (ret < 0) goto out; warnings += ret; } - if (ibt) { + if (opts.ibt) { ret = create_ibt_endbr_seal_sections(file); if (ret < 0) goto out; warnings += ret; } - if (stats) { + if (opts.orc && !list_empty(&file->insn_list)) { + ret = orc_create(file); + if (ret < 0) + goto out; + warnings += ret; + } + + + if (opts.stats) { printf("nr_insns_visited: %ld\n", nr_insns_visited); printf("nr_cfi: %ld\n", nr_cfi); printf("nr_cfi_reused: %ld\n", nr_cfi_reused); |