kernel/linux.git/scripts/kallsyms.c, branch v6.1.168

kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[]

2023-10-25T10:03:16+00:00

[ Upstream commit 19bd8981dc2ee35fdc81ab1b0104b607c917d470 ] kallsyms_seqs_of_names[] records the symbol index sorted by address, the maximum value in kallsyms_seqs_of_names[] is the number of symbols. And 2^24 = 16777216, which means that three bytes are enough to store the index. This can help us save (1 * kallsyms_num_syms) bytes of memory. Signed-off-by: Zhen Lei Signed-off-by: Luis Chamberlain Stable-dep-of: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") Signed-off-by: Sasha Levin

scripts/kallsyms: update the usage in the comment block

2023-07-27T06:50:50+00:00

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

2023-07-27T06:50:50+00:00

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

2023-07-27T06:50:50+00:00

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

2023-07-27T06:50:39+00:00

[ 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

2023-07-27T06:50:39+00:00

[ 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()

2023-07-27T06:50:39+00:00

[ 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

Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2022-10-10T19:00:45+00:00

Pull Kbuild updates from Masahiro Yamada: - Remove potentially incomplete targets when Kbuid is interrupted by SIGINT etc in case GNU Make may miss to do that when stderr is piped to another program. - Rewrite the single target build so it works more correctly. - Fix rpm-pkg builds with V=1. - List top-level subdirectories in ./Kbuild. - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms. - Avoid two different modules in lib/zstd/ having shared code, which potentially causes building the common code as build-in and modular back-and-forth. - Unify two modpost invocations to optimize the build process. - Remove head-y syntax in favor of linker scripts for placing particular sections in the head of vmlinux. - Bump the minimal GNU Make version to 3.82. - Clean up misc Makefiles and scripts. * tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits) docs: bump minimal GNU Make version to 3.82 ia64: simplify esi object addition in Makefile Revert "kbuild: Check if linker supports the -X option" kbuild: rebuild .vmlinux.export.o when its prerequisite is updated kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o zstd: Fixing mixed module-builtin objects kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols kallsyms: take the input file instead of reading stdin kallsyms: drop duplicated ignore patterns from kallsyms.c kbuild: reuse mksysmap output for kallsyms mksysmap: update comment about __crc_* kbuild: remove head-y syntax kbuild: use obj-y instead extra-y for objects placed at the head kbuild: hide error checker logs for V=1 builds kbuild: re-run modpost when it is updated kbuild: unify two modpost invocations kbuild: move vmlinux.o rule to the top Makefile kbuild: move .vmlinux.objs rule to Makefile.modpost kbuild: list sub-directories in ./Kbuild Makefile.compiler: replace cc-ifversion with compiler-specific macros ...

Merge tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2022-10-04T00:11:07+00:00

Pull kcfi updates from Kees Cook: "This replaces the prior support for Clang's standard Control Flow Integrity (CFI) instrumentation, which has required a lot of special conditions (e.g. LTO) and work-arounds. The new implementation ("Kernel CFI") is specific to C, directly designed for the Linux kernel, and takes advantage of architectural features like x86's IBT. This series retains arm64 support and adds x86 support. GCC support is expected in the future[1], and additional "generic" architectural support is expected soon[2]. Summary: - treewide: Remove old CFI support details - arm64: Replace Clang CFI support with Clang KCFI support - x86: Introduce Clang KCFI support" Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [1] Link: https://github.com/samitolvanen/llvm-project/commits/kcfi_generic [2] * tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits) x86: Add support for CONFIG_CFI_CLANG x86/purgatory: Disable CFI x86: Add types to indirectly called assembly functions x86/tools/relocs: Ignore __kcfi_typeid_ relocations kallsyms: Drop CONFIG_CFI_CLANG workarounds objtool: Disable CFI warnings objtool: Preserve special st_shndx indexes in elf_update_symbol treewide: Drop __cficanonical treewide: Drop WARN_ON_FUNCTION_MISMATCH treewide: Drop function_nocfi init: Drop __nocfi from __init arm64: Drop unneeded __nocfi attributes arm64: Add CFI error handling arm64: Add types to indirect called assembly functions psci: Fix the function type for psci_initcall_t lkdtm: Emit an indirect call for CFI tests cfi: Add type helper macros cfi: Switch to -fsanitize=kcfi cfi: Drop __CFI_ADDRESSABLE cfi: Remove CONFIG_CFI_CLANG_SHADOW ...

kallsyms: take the input file instead of reading stdin

2022-10-02T09:06:05+00:00

This gets rid of the pipe operator connected with 'cat'. Also use getopt_long() to parse the command line. Signed-off-by: Masahiro Yamada