| Date | Fri, 13 May 2022 13:21:53 -0700 | Subject | [RFC PATCH v2 15/21] objtool: Don't warn about __cfi_ preambles falling through | From | Sami Tolvanen <> |
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The __cfi_ preambles contain valid instructions, which embed KCFI type information in the following format:
__cfi_function: int3 int3 mov <id>, %eax int3 int3 function: ...
While the preambles are STT_FUNC and contain valid instructions, they are not executed and always fall through. Skip the warning for them.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- tools/objtool/check.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ca5b74603008..88f005ae6dcc 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3311,6 +3311,10 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, next_insn = next_insn_to_validate(file, insn); if (func && insn->func && func != insn->func->pfunc) { + /* Ignore KCFI type preambles, which always fall through */ + if (!strncmp(func->name, "__cfi_", 6)) + return 0; + WARN("%s() falls through to next function %s()", func->name, insn->func->name); return 1; -- 2.36.0.550.gb090851708-goog
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