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Subject[tip:x86/asm] x86/asm: Add unwind hint annotations to sync_core()
Commit-ID:  76846bf3cb09e98881cb4908385a0e899716b01f
Gitweb: http://git.kernel.org/tip/76846bf3cb09e98881cb4908385a0e899716b01f
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Tue, 11 Jul 2017 10:33:45 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 18 Jul 2017 10:57:44 +0200

x86/asm: Add unwind hint annotations to sync_core()

This enables objtool to grok the iret in the middle of a C function.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/b057be26193c11d2ed3337b2107bc7adcba42c99.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/processor.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6a79547..b27dc9b 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -22,6 +22,7 @@ struct vm86;
#include <asm/nops.h>
#include <asm/special_insns.h>
#include <asm/fpu/types.h>
+#include <asm/unwind_hints.h>

#include <linux/personality.h>
#include <linux/cache.h>
@@ -684,6 +685,7 @@ static inline void sync_core(void)
unsigned int tmp;

asm volatile (
+ UNWIND_HINT_SAVE
"mov %%ss, %0\n\t"
"pushq %q0\n\t"
"pushq %%rsp\n\t"
@@ -693,6 +695,7 @@ static inline void sync_core(void)
"pushq %q0\n\t"
"pushq $1f\n\t"
"iretq\n\t"
+ UNWIND_HINT_RESTORE
"1:"
: "=&r" (tmp), "+r" (__sp) : : "cc", "memory");
#endif
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