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) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20230816115921.GH980931@hirez.programming.kicks-ass.net
-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) &&
- insn_call_dest(insn)->fentry)
- return true;
+ if (insn->type == INSN_CALL) {
+ struct symbol *dest = insn_call_dest(insn);
+
+ if (!dest)
+ return false;
+
+ if (dest->fentry || dest->embedded_insn)
+ return true;
+ }
- if (opts.stackval && func && !is_fentry_call(insn) &&
+ if (opts.stackval && func && !is_special_call(insn) &&
!has_valid_stack_frame(&state)) {
WARN_INSN(insn, "call without frame pointer save/setup");
return 1;
!has_valid_stack_frame(&state)) {
WARN_INSN(insn, "call without frame pointer save/setup");
return 1;