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2023-07-23modpost: fix off by one in is_executable_section()Dan Carpenter
[ Upstream commit 3a3f1e573a105328a2cca45a7cfbebabbf5e3192 ] 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 <dan.carpenter@linaro.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-23modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24}Masahiro Yamada
[ Upstream commit 56a24b8ce6a7f9c4a21b2276a8644f6f3d8fc14d ] 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 <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-23modpost: fix section mismatch message for R_ARM_ABS32Masahiro Yamada
[ Upstream commit b7c63520f6703a25eebb4f8138fed764fcae1c6f ] addend_arm_rel() processes R_ARM_ABS32 in a wrong way. Here, test code. [test code 1] #include <linux/init.h> 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 <linux/init.h> 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 <get_foo>: 0: e59f3004 ldr r3, [pc, #4] @ c <get_foo+0xc> 4: e5930000 ldr r0, [r3] 8: e12fff1e bx lr c: 00000000 .word 0x00000000 00000010 <get_bar>: 10: e59f3004 ldr r3, [pc, #4] @ 1c <get_bar+0xc> 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 <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-23modpost: remove broken calculation of exception_table_entry sizeMasahiro Yamada
[ Upstream commit d0acc76a49aa917c1a455d11d32d34a01e8b2835 ] 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 <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-29modpost: fix section mismatch check for exported init/exit sectionsMasahiro Yamada
commit 28438794aba47a27e922857d27b31b74e8559143 upstream. Since commit f02e8a6596b7 ("module: Sort exported symbols"), EXPORT_SYMBOL* is placed in the individual section ___ksymtab(_gpl)+<sym> (3 leading underscores instead of 2). Since then, modpost cannot detect the bad combination of EXPORT_SYMBOL and __init/__exit. Fix the .fromsec field. Fixes: f02e8a6596b7 ("module: Sort exported symbols") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-14modpost: fix undefined behavior of is_arm_mapping_symbol()Masahiro Yamada
[ Upstream commit d6b732666a1bae0df3c3ae06925043bba34502b1 ] The return value of is_arm_mapping_symbol() is unpredictable when "$" is passed in. strchr(3) says: The strchr() and strrchr() functions return a pointer to the matched character or NULL if the character is not found. The terminating null byte is considered part of the string, so that if c is specified as '\0', these functions return a pointer to the terminator. When str[1] is '\0', strchr("axtd", str[1]) is not NULL, and str[2] is referenced (i.e. buffer overrun). Test code --------- char str1[] = "abc"; char str2[] = "ab"; strcpy(str1, "$"); strcpy(str2, "$"); printf("test1: %d\n", is_arm_mapping_symbol(str1)); printf("test2: %d\n", is_arm_mapping_symbol(str2)); Result ------ test1: 0 test2: 1 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-14modpost: fix removing numeric suffixesAlexander Lobakin
[ Upstream commit b5beffa20d83c4e15306c991ffd00de0d8628338 ] With the `-z unique-symbol` linker flag or any similar mechanism, it is possible to trigger the following: ERROR: modpost: "param_set_uint.0" [vmlinux] is a static EXPORT_SYMBOL The reason is that for now the condition from remove_dot(): if (m && (s[n + m] == '.' || s[n + m] == 0)) which was designed to test if it's a dot or a '\0' after the suffix is never satisfied. This is due to that `s[n + m]` always points to the last digit of a numeric suffix, not on the symbol next to it (from a custom debug print added to modpost): param_set_uint.0, s[n + m] is '0', s[n + m + 1] is '\0' So it's off-by-one and was like that since 2014. Fix this for the sake of any potential upcoming features, but don't bother stable-backporting, as it's well hidden -- apart from that LD flag, it can be triggered only with GCC LTO which never landed upstream. Fixes: fcd38ed0ff26 ("scripts: modpost: fix compilation warning") Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08modpost: restore the warning message for missing symbol versionsMasahiro Yamada
commit bf5c0c2231bcab677e5cdfb7f73e6c79f6d8c2d4 upstream. This log message was accidentally chopped off. I was wondering why this happened, but checking the ML log, Mark precisely followed my suggestion [1]. I just used "..." because I was too lazy to type the sentence fully. Sorry for the confusion. [1]: https://lore.kernel.org/all/CAK7LNAR6bXXk9-ZzZYpTqzFqdYbQsZHmiWspu27rtsFxvfRuVA@mail.gmail.com/ Fixes: 4a6795933a89 ("kbuild: modpost: Explicitly warn about unprototyped symbols") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Mark Brown <broonie@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-03Merge tag 'kbuild-v5.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add -s option (strict mode) to merge_config.sh to make it fail when any symbol is redefined. - Show a warning if a different compiler is used for building external modules. - Infer --target from ARCH for CC=clang to let you cross-compile the kernel without CROSS_COMPILE. - Make the integrated assembler default (LLVM_IAS=1) for CC=clang. - Add <linux/stdarg.h> to the kernel source instead of borrowing <stdarg.h> from the compiler. - Add Nick Desaulniers as a Kbuild reviewer. - Drop stale cc-option tests. - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG to handle symbols in inline assembly. - Show a warning if 'FORCE' is missing for if_changed rules. - Various cleanups * tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kbuild: redo fake deps at include/ksym/*.h kbuild: clean up objtool_args slightly modpost: get the *.mod file path more simply checkkconfigsymbols.py: Fix the '--ignore' option kbuild: merge vmlinux_link() between ARCH=um and other architectures kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh kbuild: merge vmlinux_link() between the ordinary link and Clang LTO kbuild: remove stale *.symversions kbuild: remove unused quiet_cmd_update_lto_symversions gen_compile_commands: extract compiler command from a series of commands x86: remove cc-option-yn test for -mtune= arc: replace cc-option-yn uses with cc-option s390: replace cc-option-yn uses with cc-option ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild sparc: move the install rule to arch/sparc/Makefile security: remove unneeded subdir-$(CONFIG_...) kbuild: sh: remove unused install script kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y kbuild: Switch to 'f' variants of integrated assembler flag kbuild: Shuffle blank line to improve comment meaning ...
2021-09-03modpost: get the *.mod file path more simplyMasahiro Yamada
get_src_version() strips 'o' or 'lto.o' from the end of the object file path (so, postfixlen is 1 or 5), then adds 'mod'. If you look at the code closely, mod->name already holds the base path with the extension stripped. Most of the code changes made by commit 7ac204b545f2 ("modpost: lto: strip .lto from module names") was actually unneeded. sumversion.c does not need strends(), so it can get back local in modpost.c again. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-15powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm gotoChristophe Leroy
Using asm goto in __WARN_FLAGS() and WARN_ON() allows more flexibility to GCC. For that add an entry to the exception table so that program_check_exception() knowns where to resume execution after a WARNING. Here are two exemples. The first one is done on PPC32 (which benefits from the previous patch), the second is on PPC64. unsigned long test(struct pt_regs *regs) { int ret; WARN_ON(regs->msr & MSR_PR); return regs->gpr[3]; } unsigned long test9w(unsigned long a, unsigned long b) { if (WARN_ON(!b)) return 0; return a / b; } Before the patch: 000003a8 <test>: 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc <test+0x14> 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 3c0: 80 63 00 0c lwz r3,12(r3) 3c4: 4e 80 00 20 blr 0000000000000bf0 <.test9w>: bf0: 7c 89 00 74 cntlzd r9,r4 bf4: 79 29 d1 82 rldicl r9,r9,58,6 bf8: 0b 09 00 00 tdnei r9,0 bfc: 2c 24 00 00 cmpdi r4,0 c00: 41 82 00 0c beq c0c <.test9w+0x1c> c04: 7c 63 23 92 divdu r3,r3,r4 c08: 4e 80 00 20 blr c0c: 38 60 00 00 li r3,0 c10: 4e 80 00 20 blr After the patch: 000003a8 <test>: 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc <test+0x14> 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 0000000000000c50 <.test9w>: c50: 7c 89 00 74 cntlzd r9,r4 c54: 79 29 d1 82 rldicl r9,r9,58,6 c58: 0b 09 00 00 tdnei r9,0 c5c: 7c 63 23 92 divdu r3,r3,r4 c60: 4e 80 00 20 blr c70: 38 60 00 00 li r3,0 c74: 4e 80 00 20 blr In the first exemple, we see GCC doesn't need to duplicate what happens after the trap. In the second exemple, we see that GCC doesn't need to emit a test and a branch in the likely path in addition to the trap. We've got some WARN_ON() in .softirqentry.text section so it needs to be added in the OTHER_TEXT_SECTIONS in modpost.c Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu
2021-06-17kbuild: modpost: Explicitly warn about unprototyped symbolsMark Brown
One common cause of modpost version generation failures is a failure to prototype exported assembly functions - the tooling requires this for exported functions even if they are not and should not be called from C code in order to do the version mangling for symbols. Unfortunately the error message is currently rather abstruse, simply saying that "version generation failed" and even diving into the code doesn't directly show what's going on since there's several steps between the problem and it being observed. Provide an explicit hint as to the likely cause of a version generation failure to help anyone who runs into this in future more readily diagnose and fix the problem. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25kbuild: add an elfnote for whether vmlinux is built with ltoYonghong Song
Currently, clang LTO built vmlinux won't work with pahole. LTO introduced cross-cu dwarf tag references and broke current pahole model which handles one cu as a time. The solution is to merge all cu's as one pahole cu as in [1]. We would like to do this merging only if cross-cu dwarf references happens. The LTO build mode is a pretty good indication for that. In earlier version of this patch ([2]), clang flag -grecord-gcc-switches is proposed to add to compilation flags so pahole could detect "-flto" and then merging cu's. This will increate the binary size of 1% without LTO though. Arnaldo suggested to use a note to indicate the vmlinux is built with LTO. Such a cheap way to get whether the vmlinux is built with LTO or not helps pahole but is also useful for tracing as LTO may inline/delete/demote global functions, promote static functions, etc. So this patch added an elfnote with a new type LINUX_ELFNOTE_LTO_INFO. The owner of the note is "Linux". With gcc 8.4.1 and clang trunk, without LTO, I got $ readelf -n vmlinux Displaying notes found in: .notes Owner Data size Description ... Linux 0x00000004 func description data: 00 00 00 00 ... With "readelf -x ".notes" vmlinux", I can verify the above "func" with type code 0x101. With clang thin-LTO, I got the same as above except the following: description data: 01 00 00 00 which indicates the vmlinux is built with LTO. [1] https://lore.kernel.org/bpf/20210325065316.3121287-1-yhs@fb.com/ [2] https://lore.kernel.org/bpf/20210331001623.2778934-1-yhs@fb.com/ Suggested-by: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> Signed-off-by: Yonghong Song <yhs@fb.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v12.0.0-rc4 (x86-64) Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25scripts: modpost.c: Fix a few typosBhaskar Chowdhury
s/agorithm/algorithm/ s/criterias/criteria/ s/targetting/targeting/ ....two different places. Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25kbuild: fix false-positive modpost warning when all symbols are trimmedMasahiro Yamada
Nathan reports that the mips defconfig emits the following warning: WARNING: modpost: Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped. This false-positive happens when CONFIG_TRIM_UNUSED_KSYMS is enabled, but no CONFIG option is set to 'm'. Commit a0590473c5e6 ("nfs: fix PNFS_FLEXFILE_LAYOUT Kconfig default") turned the last 'm' into 'y' for the mips defconfig, and uncovered this issue. In this case, the module feature itself is enabled, but we have no module to build. As a result, CONFIG_TRIM_UNUSED_KSYMS drops all the instances of EXPORT_SYMBOL. Then, modpost wrongly assumes vmlinux is missing because vmlinux.symvers is empty. (As another false-positive case, you can create a module that does not use any symbol of vmlinux). The current behavior is to entirely suppress the unresolved symbol warnings when vmlinux is missing just because there are too many. I found the origin of this code in the historical git tree. [1] If this is a matter of noisiness, I think modpost can display the first 10 warnings, and the number of suppressed warnings at the end. You will get a bit noisier logs when you run 'make modules' without vmlinux, but such warnings are better to show because you never know the resulting modules are actually loadable or not. This commit changes the following: - If any of input *.symver files is missing, pass -w option to let the module build keep going with warnings instead of errors. - If there are too many (10+) unresolved symbol warnings, show only the first 10, and also the number of suppressed warnings. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=1cc0e0529569bf6a94f6d49770aa6d4b599d2c46 Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-25kbuild: generate Module.symvers only when vmlinux existsMasahiro Yamada
The external module build shows the following warning if Module.symvers is missing in the kernel tree. WARNING: Symbol version dump "Module.symvers" is missing. Modules may not have dependencies or modversions. I think this is an important heads-up because the resulting modules may not work as expected. This happens when you did not build the entire kernel tree, for example, you might have prepared the minimal setups for external modules by 'make defconfig && make modules_preapre'. A problem is that 'make modules' creates Module.symvers even without vmlinux. In this case, that warning is suppressed since Module.symvers already exists in spite of its incomplete content. The incomplete (i.e. invalid) Module.symvers should not be created. This commit changes the second pass of modpost to dump symbols into modules-only.symvers. The final Module.symvers is created by concatenating vmlinux.symvers and modules-only.symvers if both exist. Module.symvers is supposed to collect symbols from both vmlinux and modules. It might be a bit confusing, and I am not quite sure if it is an official interface, but presumably it is difficult to rename it because some tools (e.g. kmod) parse it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-23Merge tag 'modules-for-v5.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull module updates from Jessica Yu: - Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These export types were introduced between 2006 - 2008. All the of the unused symbols have been long removed and gpl future symbols were converted to gpl quite a long time ago, and I don't believe these export types have been used ever since. So, I think it should be safe to retire those export types now (Christoph Hellwig) - Refactor and clean up some aged code cruft in the module loader (Christoph Hellwig) - Build {,module_}kallsyms_on_each_symbol only when livepatching is enabled, as it is the only caller (Christoph Hellwig) - Unexport find_module() and module_mutex and fix the last module callers to not rely on these anymore. Make module_mutex internal to the module loader (Christoph Hellwig) - Harden ELF checks on module load and validate ELF structures before checking the module signature (Frank van der Linden) - Fix undefined symbol warning for clang (Fangrui Song) - Fix smatch warning (Dan Carpenter) * tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: potential uninitialized return in module_kallsyms_on_each_symbol() module: remove EXPORT_UNUSED_SYMBOL* module: remove EXPORT_SYMBOL_GPL_FUTURE module: move struct symsearch to module.c module: pass struct find_symbol_args to find_symbol module: merge each_symbol_section into find_symbol module: remove each_symbol_in_section module: mark module_mutex static kallsyms: only build {,module_}kallsyms_on_each_symbol when required kallsyms: refactor {,module_}kallsyms_on_each_symbol module: use RCU to synchronize find_module module: unexport find_module and module_mutex drm: remove drm_fb_helper_modinit powerpc/powernv: remove get_cxl_module module: harden ELF info handling module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols
2021-02-08module: remove EXPORT_UNUSED_SYMBOL*Christoph Hellwig
EXPORT_UNUSED_SYMBOL* is not actually used anywhere. Remove the unused functionality as we generally just remove unused code anyway. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2021-02-08module: remove EXPORT_SYMBOL_GPL_FUTUREChristoph Hellwig
As far as I can tell this has never been used at all, and certainly not any time recently. Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2021-01-14modpost: lto: strip .lto from module namesSami Tolvanen
With LTO, everything is compiled into LLVM bitcode, so we have to link each module into native code before modpost. Kbuild uses the .lto.o suffix for these files, which also ends up in module information. This change strips the unnecessary .lto suffix from the module name. Suggested-by: Bill Wendling <morbo@google.com> Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-11-samitolvanen@google.com
2020-12-21modpost: turn static exports into errorQuentin Perret
Using EXPORT_SYMBOL*() on static functions is fundamentally wrong. Modpost currently reports that as a warning, but clearly this is not a pattern we should allow, and all in-tree occurences should have been fixed by now. So, promote the warn() message to error() to make sure this never happens again. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Matthias Maennich <maennich@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21modpost: turn section mismatches to error from fatal()Masahiro Yamada
There is code that reports static EXPORT_SYMBOL a few lines below. It is not a good idea to bail out here. I renamed sec_mismatch_fatal to sec_mismatch_warn_only (with logical inversion) to match to CONFIG_SECTION_MISMATCH_WARN_ONLY. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21modpost: change license incompatibility to error() from fatal()Masahiro Yamada
Change fatal() to error() to continue running to report more possible issues. There is no difference in the fact that modpost will fail anyway. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21modpost: turn missing MODULE_LICENSE() into errorMasahiro Yamada
Do not create modules with no license tag. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21modpost: refactor error handling and clarify error/fatal differenceMasahiro Yamada
We have 3 log functions. fatal() is special because it lets modpost bail out immediately. The difference between warn() and error() is the only prefix parts ("WARNING:" vs "ERROR:"). In my understanding, the expected handling of error() is to propagate the return code of the function to the exit code of modpost, as check_exports() etc. already does. This is a good manner in general because we should display as many error messages as possible in a single run of modpost. What is annoying about fatal() is that it kills modpost at the first error. People would need to run Kbuild again and again until they fix all errors. But, unfortunately, people tend to do: "This case should not be allowed. Let's replace warn() with fatal()." One of the reasons is probably it is tedious to manually hoist the error code to the main() function. This commit refactors error() so any single call for it automatically makes modpost return the error code. I also added comments in modpost.h for warn(), error(), and fatal(). Please use fatal() only when you have a strong reason to do so. For example: - Memory shortage (i.e. malloc() etc. has failed) - The ELF file is broken, and there is no point to continue parsing - Something really odd has happened For general coding errors, please use error(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Quentin Perret <qperret@google.com>
2020-12-21modpost: rename merror() to error()Masahiro Yamada
The log function names, warn(), merror(), fatal() are inconsistent. Commit 2a11665945d5 ("kbuild: distinguish between errors and warnings in modpost") intentionally chose merror() to avoid the conflict with the library function error(). See man page of error(3). But, we are already causing the conflict with warn() because it is also a library function. See man page of warn(3). err() would be a problem for the same reason. The common technique to work around name conflicts is to use macros. For example: /* in a header */ #define error(fmt, ...) __error(fmt, ##__VA_ARGS__) #define warn(fmt, ...) __warn(fmt, ##__VA_ARGS__) /* function definition */ void __error(const char *fmt, ...) { <our implementation> } void __warn(const char *fmt, ...) { <our implementation> } In this way, we can implement our own warn() and error(), still we can include <error.h> and <err.h> with no problem. And, commit 93c95e526a4e ("modpost: rework and consolidate logging interface") already did that. Since the log functions are all macros, we can use error() without causing "conflicting types" errors. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-25treewide: Convert macro and uses of __section(foo) to __section("foo")Joe Perches
Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-27modpost: explain why we can't use strsepWolfram Sang
Mention why we open-code strsep, so it is clear that it is intentional. Fixes: 736bb11898ef ("modpost: remove use of non-standard strsep() in HOSTCC code") Signed-off-by: Wolfram Sang <wsa@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-07-07modpost: remove use of non-standard strsep() in HOSTCC codeH. Nikolaus Schaller
strsep() is neither standard C nor POSIX and used outside the kernel code here. Using it here requires that the build host supports it out of the box which is e.g. not true for a Darwin build host and using a cross-compiler. This leads to: scripts/mod/modpost.c:145:2: warning: implicit declaration of function 'strsep' [-Wimplicit-function-declaration] return strsep(stringp, "\n"); ^ and a segfault when running MODPOST. See also: https://stackoverflow.com/a/7219504 So let's replace this by strchr() instead of using strsep(). It does not hurt kernel size or speed since this code is run on the build host. Fixes: ac5100f5432967 ("modpost: add read_text_file() and get_line() helpers") Co-developed-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06Merge tag 'kbuild-v5.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32 - ensure to rebuild all objects when the compiler is upgraded - exclude system headers from dependency tracking and fixdep processing - fix potential bit-size mismatch between the kernel and BPF user-mode helper - add the new syntax 'userprogs' to build user-space programs for the target architecture (the same arch as the kernel) - compile user-space sample code under samples/ for the target arch instead of the host arch - make headers_install fail if a CONFIG option is leaked to user-space - sanitize the output format of scripts/checkstack.pl - handle ARM 'push' instruction in scripts/checkstack.pl - error out before modpost if a module name conflict is found - error out when multiple directories are passed to M= because this feature is broken for a long time - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info - a lot of cleanups of modpost - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the second pass of modpost - do not run the second pass of modpost if nothing in modules is updated - install modules.builtin(.modinfo) by 'make install' as well as by 'make modules_install' because it is useful even when CONFIG_MODULES=n - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ to allow users to use alternatives such as pigz, pbzip2, etc. * tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits) kbuild: add variables for compression tools Makefile: install modules.builtin even if CONFIG_MODULES=n mksysmap: Fix the mismatch of '.L' symbols in System.map kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS modpost: change elf_info->size to size_t modpost: remove is_vmlinux() helper modpost: strip .o from modname before calling new_module() modpost: set have_vmlinux in new_module() modpost: remove mod->skip struct member modpost: add mod->is_vmlinux struct member modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}() modpost: remove mod->is_dot_o struct member modpost: move -d option in scripts/Makefile.modpost modpost: remove -s option modpost: remove get_next_text() and make {grab,release_}file static modpost: use read_text_file() and get_line() for reading text files modpost: avoid false-positive file open error modpost: fix potential mmap'ed file overrun in get_src_version() modpost: add read_text_file() and get_line() helpers modpost: do not call get_modinfo() for vmlinux(.o) ...
2020-06-06modpost: change elf_info->size to size_tMasahiro Yamada
Align with the mmap / munmap APIs. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove is_vmlinux() helperMasahiro Yamada
Now that is_vmlinux() is called only in new_module(), we can inline the function call. modname is the basename with '.o' is stripped. No need to compare it with 'vmlinux.o'. vmlinux is always located at the current working directory. No need to strip the directory path. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: strip .o from modname before calling new_module()Masahiro Yamada
new_module() conditionally strips the .o because the modname has .o suffix when it is called from read_symbols(), but no .o when it is called from read_dump(). It is clearer to strip .o in read_symbols(). I also used flexible-array for mod->name. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: set have_vmlinux in new_module()Masahiro Yamada
Set have_vmlinux flag in a single place. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove mod->skip struct memberMasahiro Yamada
The meaning of 'skip' is obscure since it does not explain "what to skip". mod->skip is set when it is vmlinux or the module info came from a dump file. So, mod->skip is equivalent to (mod->is_vmlinux || mod->from_dump). For the check in write_namespace_deps_files(), mod->is_vmlinux is unneeded because the -d option is not passed in the first pass of modpost. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: add mod->is_vmlinux struct memberMasahiro Yamada
is_vmlinux() is called in several places to check whether the current module is vmlinux or not. It is faster and clearer to check mod->is_vmlinux flag. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()Masahiro Yamada
check_exports() is never called for vmlinux because mod->skip is set for vmlinux. Hence, check_for_gpl_usage() and check_for_unused() are not called for vmlinux, either. is_vmlinux() is always false here. Remove the is_vmlinux() calls, and hard-code the ".ko" suffix. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove mod->is_dot_o struct memberMasahiro Yamada
Previously, there were two cases where mod->is_dot_o is unset: [1] the executable 'vmlinux' in the second pass of modpost [2] modules loaded by read_dump() I think [1] was intended usage to distinguish 'vmlinux.o' and 'vmlinux'. Now that modpost does not parse the executable 'vmlinux', this case does not happen. [2] is obscure, maybe a bug. Module.symver stores module paths without extension. So, none of modules loaded by read_dump() has the .o suffix, and new_module() unsets ->is_dot_o. Anyway, it is not a big deal because handle_symbol() is not called for the case. To sum up, all the parsed ELF files are .o files. mod->is_dot_o is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove -s optionMasahiro Yamada
The -s option was added by commit 8d8d8289df65 ("kbuild: do not do section mismatch checks on vmlinux in 2nd pass"). Now that the second pass does not parse vmlinux, this option is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: remove get_next_text() and make {grab,release_}file staticMasahiro Yamada
get_next_line() is no longer used. Remove. grab_file() and release_file() are only used in modpost.c. Make them static. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: use read_text_file() and get_line() for reading text filesMasahiro Yamada
grab_file() mmaps a file, but it is not so efficient here because get_next_line() copies every line to the temporary buffer anyway. read_text_file() and get_line() are simpler. get_line() exploits the library function strchr(). Going forward, the missing *.symvers or *.cmd is a fatal error. This should not happen because scripts/Makefile.modpost guards the -i option files with $(wildcard $(input-symdump)). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: add read_text_file() and get_line() helpersMasahiro Yamada
modpost uses grab_file() to open a file, but it is not suitable for a text file because the mmap'ed file is not terminated by null byte. Actually, I see some issues for the use of grab_file(). The new helper, read_text_file() loads the whole file content into a malloc'ed buffer, and appends a null byte. Then, get_line() reads each line. To handle text files, I intend to replace as follows: grab_file() -> read_text_file() get_new_line() -> get_line() Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: do not call get_modinfo() for vmlinux(.o)Masahiro Yamada
The three calls of get_modinfo() ("license", "import_ns", "version") always return NULL for vmlinux(.o) because the built-in module info is prefixed with __MODULE_INFO_PREFIX. It is harmless to call get_modinfo(), but there is no point to search for what apparently does not exist. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: drop RCS/CVS $Revision handling in MODULE_VERSION()Masahiro Yamada
As far as I understood, this code gets rid of '$Revision$' or '$Revision:' of CVS, RCS or whatever in MODULE_VERSION() tags. Remove the primeval code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: show warning if vmlinux is not found when processing modulesMasahiro Yamada
check_exports() does not print warnings about unresolved symbols if vmlinux is missing because there would be too many. This situation happens when you do 'make modules' from the clean tree, or compile external modules against a kernel tree that has not been completely built. It is dangerous to not check unresolved symbols because you might be building useless modules. At least it should be warned. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: invoke modpost only when input files are updatedMasahiro Yamada
Currently, the second pass of modpost is always invoked when you run 'make' or 'make modules' even if none of modules is changed. Use if_changed to invoke it only when it is necessary. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: re-add -e to set external_module flagMasahiro Yamada
Previously, the -i option had two functions; load a symbol dump file, and set the external_module flag. I want to assign a dedicate option for each of them. Going forward, the -i is used to load a symbol dump file, and the -e to set the external_module flag. With this, we will be able to use -i for loading in-kernel symbols. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: rename ext_sym_list to dump_listMasahiro Yamada
The -i option is used to include Modules.symver as well as files from $(KBUILD_EXTRA_SYMBOLS). Make the struct and variable names more generic. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: allow to pass -i option multiple times to remove -e optionMasahiro Yamada
Now that there is no difference between -i and -e, they can be unified. Make modpost accept the -i option multiple times, then remove -e. I will reuse -e for a different purpose. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06modpost: track if the symbol origin is a dump file or ELF objectMasahiro Yamada
The meaning of sym->kernel is obscure; it is set for in-kernel symbols loaded from Modules.symvers. This happens only when we are building external modules, and it is used to determine whether to dump symbols to $(KBUILD_EXTMOD)/Modules.symvers It is clearer to remember whether the symbol or module came from a dump file or ELF object. This changes the KBUILD_EXTRA_SYMBOLS behavior. Previously, symbols loaded from KBUILD_EXTRA_SYMBOLS are accumulated into the current $(KBUILD_EXTMOD)/Modules.symvers Going forward, they will be only used to check symbol references, but not dumped into the current $(KBUILD_EXTMOD)/Modules.symvers. I believe this makes more sense. sym->vmlinux will have no user. Remove it too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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