diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-10-26 15:01:34 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-10-29 00:25:25 +0300 |
| commit | dd003edeffa3cb87bc9862582004f405d77d7670 (patch) | |
| tree | 9454b4bcf4fd88610280877db064b766925af3e6 /tools/objtool | |
| parent | 1739c66eb7bd5f27f1b69a5a26e10e8327d1e136 (diff) | |
| download | linux-dd003edeffa3cb87bc9862582004f405d77d7670.tar.xz | |
objtool: Explicitly avoid self modifying code in .altinstr_replacement
Assume ALTERNATIVE()s know what they're doing and do not change, or
cause to change, instructions in .altinstr_replacement sections.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120309.722511775@infradead.org
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/check.c | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index fdbc6d2c5597..8ab6f24f8753 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -993,18 +993,27 @@ static void remove_insn_ops(struct instruction *insn) } } -static void add_call_dest(struct objtool_file *file, struct instruction *insn, - struct symbol *dest, bool sibling) +static void annotate_call_site(struct objtool_file *file, + struct instruction *insn, bool sibling) { struct reloc *reloc = insn_reloc(file, insn); + struct symbol *sym = insn->call_dest; - insn->call_dest = dest; - if (!dest) + if (!sym) + sym = reloc->sym; + + /* + * Alternative replacement code is just template code which is + * sometimes copied to the original instruction. For now, don't + * annotate it. (In the future we might consider annotating the + * original instruction if/when it ever makes sense to do so.) + */ + if (!strcmp(insn->sec->name, ".altinstr_replacement")) return; - if (insn->call_dest->static_call_tramp) { - list_add_tail(&insn->call_node, - &file->static_call_list); + if (sym->static_call_tramp) { + list_add_tail(&insn->call_node, &file->static_call_list); + return; } /* @@ -1012,7 +1021,7 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn, * so they need a little help, NOP out any KCOV calls from noinstr * text. */ - if (insn->sec->noinstr && insn->call_dest->kcov) { + if (insn->sec->noinstr && sym->kcov) { if (reloc) { reloc->type = R_NONE; elf_write_reloc(file->elf, reloc); @@ -1024,9 +1033,10 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn, : arch_nop_insn(insn->len)); insn->type = sibling ? INSN_RETURN : INSN_NOP; + return; } - if (mcount && insn->call_dest->fentry) { + if (mcount && sym->fentry) { if (sibling) WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); @@ -1041,9 +1051,17 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn, insn->type = INSN_NOP; - list_add_tail(&insn->mcount_loc_node, - &file->mcount_loc_list); + list_add_tail(&insn->mcount_loc_node, &file->mcount_loc_list); + return; } +} + +static void add_call_dest(struct objtool_file *file, struct instruction *insn, + struct symbol *dest, bool sibling) +{ + insn->call_dest = dest; + if (!dest) + return; /* * Whatever stack impact regular CALLs have, should be undone @@ -1053,6 +1071,8 @@ static void add_call_dest(struct objtool_file *file, struct instruction *insn, * are converted to JUMP, see read_intra_function_calls(). */ remove_insn_ops(insn); + + annotate_call_site(file, insn, sibling); } /* |