From: Peter Zijlstra Date: Wed, 16 Aug 2023 11:59:21 +0000 (+0200) Subject: objtool/x86: Fixup frame-pointer vs rethunk X-Git-Tag: v5.10.192~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23e59874657c6396abb82544f6f60d100d84ee6a;p=thirdparty%2Fkernel%2Fstable.git objtool/x86: Fixup frame-pointer vs rethunk commit dbf46008775516f7f25c95b7760041c286299783 upstream. For stack-validation of a frame-pointer build, objtool validates that every CALL instruction is preceded by a frame-setup. The new SRSO return thunks violate this with their RSB stuffing trickery. Extend the __fentry__ exception to also cover the embedded_insn case used for this. This cures: vmlinux.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup Fixes: 4ae68b26c3ab ("objtool/x86: Fix SRSO mess") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20230816115921.GH980931@hirez.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman --- diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 1d58cc5ca6e87..965c055aa8088 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2079,12 +2079,17 @@ static int decode_sections(struct objtool_file *file) return 0; } -static bool is_fentry_call(struct instruction *insn) +static bool is_special_call(struct instruction *insn) { - if (insn->type == INSN_CALL && - insn->call_dest && - insn->call_dest->fentry) - return true; + if (insn->type == INSN_CALL) { + struct symbol *dest = insn->call_dest; + + if (!dest) + return false; + + if (dest->fentry) + return true; + } return false; } @@ -2958,7 +2963,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, if (ret) return ret; - if (!no_fp && func && !is_fentry_call(insn) && + if (!no_fp && func && !is_special_call(insn) && !has_valid_stack_frame(&state)) { WARN_FUNC("call without frame pointer save/setup", sec, insn->offset);