diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2026-04-23 15:53:17 -0700 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2026-05-04 21:16:07 -0700 |
| commit | fc0bb9915bce0c333f918ca76958d804ccd79f89 (patch) | |
| tree | 4623f5e23f16b8d185f7a59b1f61c625947594c7 /tools/objtool/include | |
| parent | cca84cb12908f1cfcecaef80a7692017e2d6a945 (diff) | |
objtool: Grow __cfi_* prefix symbols for all CFI+CALL_PADDING
For all CONFIG_CFI+CONFIG_CALL_PADDING configs, for C functions, the
__cfi_ symbols only cover the 5-byte kCFI type hash. After that there
also N bytes of NOP padding between the hash and the function entry
which aren't associated with any symbol.
The NOPs can be replaced with actual code at runtime. Without a symbol,
unwinders and tooling have no way of knowing where those bytes belong.
Grow the existing __cfi_* symbols to fill that gap.
Note that assembly functions with SYM_TYPED_FUNC_START() aren't affected
by this issue, their __cfi_ symbols also cover the padding.
Also, CONFIG_PREFIX_SYMBOLS has no reason to exist: CONFIG_CALL_PADDING
is what causes the compiler to emit NOP padding before function entry
(via -fpatchable-function-entry), so it's the right condition for
creating prefix symbols.
Remove CONFIG_PREFIX_SYMBOLS, as it's no longer needed. Simplify the
LONGEST_SYM_KUNIT_TEST dependency accordingly. Rework objtool's
arguments a bit to handle the variety of prefix/cfi-related cases.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'tools/objtool/include')
| -rw-r--r-- | tools/objtool/include/objtool/builtin.h | 7 | ||||
| -rw-r--r-- | tools/objtool/include/objtool/elf.h | 1 |
2 files changed, 5 insertions, 3 deletions
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index b9e229ed4dc0..e844e9c82b7b 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -9,8 +9,8 @@ struct opts { /* actions: */ - bool cfi; bool checksum; + const char *disas; bool dump_orc; bool hack_jump_label; bool hack_noinstr; @@ -20,6 +20,7 @@ struct opts { bool noabs; bool noinstr; bool orc; + int prefix; bool retpoline; bool rethunk; bool unret; @@ -27,14 +28,14 @@ struct opts { bool stackval; bool static_call; bool uaccess; - int prefix; - const char *disas; /* options: */ bool backtrace; bool backup; + bool cfi; const char *debug_checksum; bool dryrun; + bool fineibt; bool link; bool mnop; bool module; diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h index e452784df702..305183f30a33 100644 --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -199,6 +199,7 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec, struct symbol *sym, s64 addend); +int elf_write_symbol(struct elf *elf, struct symbol *sym); int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset, unsigned int len, const char *insn); |