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Message-Id: <b46ad8966b1575978b7b9cee467fa6d63a089a4d.1610652862.git.jpoimboe@redhat.com>
Date: Thu, 14 Jan 2021 13:40:12 -0600
From: Josh Poimboeuf <jpoimboe@...hat.com>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <peterz@...radead.org>,
Sami Tolvanen <samitolvanen@...gle.com>,
Sedat Dilek <sedat.dilek@...il.com>,
Kees Cook <keescook@...omium.org>,
Nick Desaulniers <ndesaulniers@...gle.com>,
clang-built-linux@...glegroups.com,
Miroslav Benes <mbenes@...e.cz>,
Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH 16/21] 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.
Cc: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
arch/x86/kernel/ftrace_64.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index 1bf568d901b1..7c273846c687 100644
--- 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
--
2.29.2
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