user/sven/linux.git/scripts, branch v6.1.43

scripts/kallsyms: update the usage in the comment block

2023-07-27T06:50:50Z

commit 79549da691edd4874c19d99c578a134471817c47 upstream. Commit 010a0aad39fc ("kallsyms: Correctly sequence symbols when CONFIG_LTO_CLANG=y") added --lto-clang, and updated the usage() function, but not the comment. Update it in the same way. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Signed-off-by: Greg Kroah-Hartman

scripts/kallsyms.c Make the comment up-to-date with current implementation

2023-07-27T06:50:50Z

commit adc40221bf676f3e722d135889a7b913b4162dc2 upstream. The comment in scripts/kallsyms.c describing the usage of scripts/kallsyms does not reflect the latest implementation. Fix the comment to be equivalent to what the usage() function prints. Signed-off-by: Yuma Ueda Reviewed-by: Miguel Ojeda Link: https://lore.kernel.org/r/20221118133631.4554-1-cyan@0x00a1e9.dev Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

kallsyms: add kallsyms_seqs_of_names to list of special symbols

2023-07-27T06:50:50Z

commit ced0f245ed951e2b8bd68f79c15238d7dd253662 upstream. My randconfig build setup ran into another kallsyms warning: Inconsistent kallsyms data Try make KALLSYMS_EXTRA_PASS=1 as a workaround After adding some debugging code to kallsyms.c, I saw that the recently added kallsyms_seqs_of_names symbol can sometimes cause the second stage table to be slightly longer than the first stage, which makes the build inconsistent. Add it to the exception table that contains all other kallsyms-generated symbols. Fixes: 60443c88f3a8 ("kallsyms: Improve the performance of kallsyms_lookup_name()") Signed-off-by: Arnd Bergmann Reviewed-by: Zhen Lei Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

kallsyms: strip LTO-only suffixes from promoted global functions

2023-07-27T06:50:39Z

[ Upstream commit 8cc32a9bbf2934d90762d9de0187adcb5ad46a11 ] Commit 6eb4bd92c1ce ("kallsyms: strip LTO suffixes from static functions") stripped all function/variable suffixes started with '.' regardless of whether those suffixes are generated at LTO mode or not. In fact, as far as I know, in LTO mode, when a static function/variable is promoted to the global scope, '.llvm.<...>' suffix is added. The existing mechanism breaks live patch for a LTO kernel even if no .llvm.<...> symbols are involved. For example, for the following kernel symbols: $ grep bpf_verifier_vlog /proc/kallsyms ffffffff81549f60 t bpf_verifier_vlog ffffffff8268b430 d bpf_verifier_vlog._entry ffffffff8282a958 d bpf_verifier_vlog._entry_ptr ffffffff82e12a1f d bpf_verifier_vlog.__already_done 'bpf_verifier_vlog' is a static function. '_entry', '_entry_ptr' and '__already_done' are static variables used inside 'bpf_verifier_vlog', so llvm promotes them to file-level static with prefix 'bpf_verifier_vlog.'. Note that the func-level to file-level static function promotion also happens without LTO. Given a symbol name 'bpf_verifier_vlog', with LTO kernel, current mechanism will return 4 symbols to live patch subsystem which current live patching subsystem cannot handle it. With non-LTO kernel, only one symbol is returned. In [1], we have a lengthy discussion, the suggestion is to separate two cases: (1). new symbols with suffix which are generated regardless of whether LTO is enabled or not, and (2). new symbols with suffix generated only when LTO is enabled. The cleanup_symbol_name() should only remove suffixes for case (2). Case (1) should not be changed so it can work uniformly with or without LTO. This patch removed LTO-only suffix '.llvm.<...>' so live patching and tracing should work the same way for non-LTO kernel. The cleanup_symbol_name() in scripts/kallsyms.c is also changed to have the same filtering pattern so both kernel and kallsyms tool have the same expectation on the order of symbols. [1] https://lore.kernel.org/live-patching/20230615170048.2382735-1-song@kernel.org/T/#u Fixes: 6eb4bd92c1ce ("kallsyms: strip LTO suffixes from static functions") Reported-by: Song Liu Signed-off-by: Yonghong Song Reviewed-by: Zhen Lei Reviewed-by: Nick Desaulniers Acked-by: Song Liu Link: https://lore.kernel.org/r/20230628181926.4102448-1-yhs@fb.com Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

kallsyms: Correctly sequence symbols when CONFIG_LTO_CLANG=y

2023-07-27T06:50:39Z

[ Upstream commit 010a0aad39fccceba4a07d30d163158a39c704f3 ] LLVM appends various suffixes for local functions and variables, suffixes observed: - foo.llvm.[0-9a-f]+ - foo.[0-9a-f]+ Therefore, when CONFIG_LTO_CLANG=y, kallsyms_lookup_name() needs to truncate the suffix of the symbol name before comparing the local function or variable name. Old implementation code: - if (strcmp(namebuf, name) == 0) - return kallsyms_sym_address(i); - if (cleanup_symbol_name(namebuf) && strcmp(namebuf, name) == 0) - return kallsyms_sym_address(i); The preceding process is traversed by address from low to high. That is, for those with the same name after the suffix is removed, the one with the smallest address is returned first. Therefore, when sorting in the tool, if the raw names are the same, they should be sorted by address in ascending order. ASCII[.] = 2e ASCII[0-9] = 30,39 ASCII[A-Z] = 41,5a ASCII[_] = 5f ASCII[a-z] = 61,7a According to the preceding ASCII code values, the following sorting result is strictly followed. --------------------------------- | main-key | sub-key | |---------------------------------| | | addr_lowest | | | ... | | . | ... | | | addr_highest | |---------------------------------| | ? | | //? is [_A-Za-z0-9] --------------------------------- Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain Stable-dep-of: 8cc32a9bbf29 ("kallsyms: strip LTO-only suffixes from promoted global functions") Signed-off-by: Sasha Levin

kallsyms: Improve the performance of kallsyms_lookup_name()

2023-07-27T06:50:39Z

[ Upstream commit 60443c88f3a89fd303a9e8c0e84895910675c316 ] Currently, to search for a symbol, we need to expand the symbols in 'kallsyms_names' one by one, and then use the expanded string for comparison. It's O(n). If we sort names in ascending order like addresses, we can also use binary search. It's O(log(n)). In order not to change the implementation of "/proc/kallsyms", the table kallsyms_names[] is still stored in a one-to-one correspondence with the address in ascending order. Add array kallsyms_seqs_of_names[], it's indexed by the sequence number of the sorted names, and the corresponding content is the sequence number of the sorted addresses. For example: Assume that the index of NameX in array kallsyms_seqs_of_names[] is 'i', the content of kallsyms_seqs_of_names[i] is 'k', then the corresponding address of NameX is kallsyms_addresses[k]. The offset in kallsyms_names[] is get_symbol_offset(k). Note that the memory usage will increase by (4 * kallsyms_num_syms) bytes, the next two patches will reduce (1 * kallsyms_num_syms) bytes and properly handle the case CONFIG_LTO_CLANG=y. Performance test results: (x86) Before: min=234, max=10364402, avg=5206926 min=267, max=11168517, avg=5207587 After: min=1016, max=90894, avg=7272 min=1014, max=93470, avg=7293 The average lookup performance of kallsyms_lookup_name() improved 715x. Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain Stable-dep-of: 8cc32a9bbf29 ("kallsyms: strip LTO-only suffixes from promoted global functions") Signed-off-by: Sasha Levin

kbuild: Disable GCOV for *.mod.o

2023-07-19T14:21:44Z

[ Upstream commit 25a21fbb934a0d989e1858f83c2ddf4cfb2ebe30 ] With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, including the *.mod.o. As we filter out CC_FLAGS_CFI for *.mod.o, the compiler won't generate type hashes for the injected functions, and therefore indirectly calling them during module loading trips indirect call checking. Enabling CFI for *.mod.o isn't sufficient to fix this issue after commit 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization"), as *.mod.o aren't processed by objtool, which means any hashes emitted there won't be randomized. Therefore, in addition to disabling CFI for *.mod.o, also disable GCOV, as the object files don't otherwise contain any executable code. Fixes: cf68fffb66d6 ("add support for Clang CFI") Reported-by: Joe Fradley Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

modpost: fix off by one in is_executable_section()

2023-07-19T14:21:42Z

[ 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 Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24}

2023-07-19T14:21:41Z

[ 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 Signed-off-by: Sasha Levin

modpost: fix section mismatch message for R_ARM_ABS32

2023-07-19T14:21:41Z

[ Upstream commit b7c63520f6703a25eebb4f8138fed764fcae1c6f ] 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 Signed-off-by: Sasha Levin