kernel/linux.git/scripts/mod/modpost.h, branch v6.6.132

modpost: Optimize symbol search from linear to binary search

2024-04-10T14:35:47+00:00

[ Upstream commit 4074532758c5c367d3fcb8d124150824a254659d ] Modify modpost to use binary search for converting addresses back into symbol references. Previously it used linear search. This change saves a few seconds of wall time for defconfig builds, but can save several minutes on allyesconfigs. Before: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 198.38user 1.27system 3:19.71elapsed After: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 11.91user 0.85system 0:12.78elapsed Signed-off-by: Jack Brennen Tested-by: Nick Desaulniers Signed-off-by: Masahiro Yamada Stable-dep-of: 1102f9f85bf6 ("modpost: do not make find_tosym() return NULL") Signed-off-by: Sasha Levin

modpost: clean up MIPS64 little endian relocation code

2023-07-31T14:42:14+00:00

MIPS64 little endian target has an odd encoding of r_info. This commit makes the special handling less ugly. It is still ugly, but #if conditionals will go away, at least. Signed-off-by: Masahiro Yamada

kbuild: generate KSYMTAB entries by modpost

2023-06-22T12:17:10+00:00

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

modpost: remove is_shndx_special() check from section_rel(a)

2023-05-28T11:35:16+00:00

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

modpost: refactor get_secindex()

2022-08-03T13:56:46+00:00

SPECIAL() is only used in get_secindex(). Squash it. Make the code more readable with more comments. Signed-off-by: Masahiro Yamada

modpost: remove unused Elf_Sword macro

2022-08-03T10:37:59+00:00

Commit 9ad21c3f3ecf ("kbuild: try harder to find symbol names in modpost") added Elf_Sword (in a wrong way), but did not use it at all. BTW, the current code looks weird. The fix for the 32-bit part would be: Elf64_Sword --> Elf32_Sword (inconsistet prefix, Elf32_ vs Elf64_) The fix for the 64-bit part would be: Elf64_Sxword --> Elf64_Sword (the size is different between Sword and Sxword) Note: Elf32_Sword == Elf64_Sword == int32_t Elf32_Sxword == Elf64_Sxword == int64_t Anyway, let's drop unused code instead of fixing it. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

modpost: use sym_get_data() to get module device_table data

2022-07-27T12:18:00+00:00

Use sym_get_data() to replace the long code. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

modpost: reuse ARRAY_SIZE() macro for section_mismatch()

2022-05-27T07:15:40+00:00

Move ARRAY_SIZE() from file2alias.c to modpost.h to reuse it in section_mismatch(). Also, move the variable 'check' inside the for-loop. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

modpost: remove left-over cross_compile declaration

2022-05-11T12:46:39+00:00

This is a remnant of commit 6543becf26ff ("mod/file2alias: make modalias generation safe for cross compiling"). Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

modpost: dump Module.symvers in the same order of modules.order

2022-05-07T18:17:01+00:00

modpost dumps the exported symbols into Module.symvers, but currently in random order because it iterates in the hash table. Add a linked list of exported symbols in struct module, so we can iterate on symbols per module. This commit makes Module.symvers much more readable; the outer loop in write_dump() iterates over the modules in the order of modules.order, and the inner loop dumps symbols in each module. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers