x86/ftrace: Support objtool vmlinux.o validation in ftrace_64.S

With objtool vmlinux.o validation of return_to_handler(), now that objtool has visibility inside the retpoline, jumping from EMPTY state to a proper function state results in a stack state mismatch. return_to_handler() is actually quite normal despite the underlying magic. Just annotate it as a normal function. Acked-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Link: https://lore.kernel.org/r/14f48e623f61dbdcd84cf27a56ed8ccae73199ef.1611263462.git.jpoimboe@redhat.com
ashr · Jan 26, 2021 · 7cae4b1 · 7cae4b1
1 parent 8269485
commit 7cae4b1
Showing 1 changed file with 2 additions and 3 deletions.
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
@@ -334,8 +334,7 @@ SYM_FUNC_START(ftrace_graph_caller)
 	retq
 SYM_FUNC_END(ftrace_graph_caller)
 
-SYM_CODE_START(return_to_handler)
-	UNWIND_HINT_EMPTY
+SYM_FUNC_START(return_to_handler)
 	subq  $24, %rsp
 
 	/* Save the return values */
@@ -350,5 +349,5 @@ SYM_CODE_START(return_to_handler)
 	movq (%rsp), %rax
 	addq $24, %rsp
 	JMP_NOSPEC rdi
-SYM_CODE_END(return_to_handler)
+SYM_FUNC_END(return_to_handler)
 #endif