Messages in this thread Patch in this message | | | Date | Wed, 09 Aug 2023 09:12:31 +0200 | From | Peter Zijlstra <> | Subject | [RFC][PATCH 13/17] objtool/x86: Add arch_is_offset_insn() |
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Add a little wrappery to identify the magic symbols that are actually inside another instruction -- yay for variable length instruction encoding.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- tools/objtool/arch/x86/decode.c | 6 ++++++ tools/objtool/check.c | 13 ++++++++++--- tools/objtool/include/objtool/arch.h | 1 + tools/objtool/include/objtool/elf.h | 1 + 4 files changed, 18 insertions(+), 3 deletions(-)
--- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -826,3 +826,9 @@ bool arch_is_rethunk(struct symbol *sym) { return !strcmp(sym->name, "__x86_return_thunk"); } + +bool arch_is_offset_insn(struct symbol *sym) +{ + return !strcmp(sym->name, "zen_return_thunk") || + !strcmp(sym->name, "srso_safe_ret"); +} --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -459,8 +459,7 @@ static int decode_instructions(struct ob * Both zen_return_thunk() and srso_safe_ret() are embedded inside * another instruction and objtool doesn't grok that. Skip validating them. */ - if (!strcmp(func->name, "zen_return_thunk") || - !strcmp(func->name, "srso_safe_ret") || func->alias != func) + if (func->offset_insn || func->alias != func) continue; if (!find_insn(file, sec, func->offset)) { @@ -1303,6 +1302,11 @@ __weak bool arch_is_rethunk(struct symbo return false; } +__weak bool arch_is_offset_insn(struct symbol *sym) +{ + return false; +} + static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn) { struct reloc *reloc; @@ -1588,7 +1592,7 @@ static int add_jump_destinations(struct * middle of another instruction. Objtool only * knows about the outer instruction. */ - if (sym && !strcmp(sym->name, "zen_return_thunk")) { + if (sym && sym->offset_insn) { add_return_call(file, insn, false); continue; } @@ -2507,6 +2511,9 @@ static int classify_symbols(struct objto if (arch_is_rethunk(func)) func->return_thunk = true; + if (arch_is_offset_insn(func)) + func->offset_insn = true; + if (arch_ftrace_match(func->name)) func->fentry = true; --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -90,6 +90,7 @@ int arch_decode_hint_reg(u8 sp_reg, int bool arch_is_retpoline(struct symbol *sym); bool arch_is_rethunk(struct symbol *sym); +bool arch_is_offset_insn(struct symbol *sym); int arch_rewrite_retpolines(struct objtool_file *file); --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -66,6 +66,7 @@ struct symbol { u8 fentry : 1; u8 profiling_func : 1; u8 warned : 1; + u8 offset_insn : 1; struct list_head pv_target; struct reloc *relocs; };
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