[PATCH v2 7/8] x86/asm: add unwind hint annotations to sync_core()

From: Josh Poimboeuf <jpoimboe@redhat.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>, Jiri Slaby <jslaby@suse.cz>,
	Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v2 7/8] x86/asm: add unwind hint annotations to sync_core()
Date: Wed, 28 Jun 2017 10:11:11 -0500	[thread overview]
Message-ID: <7edc88410886572b552dc863e2bed9aa068cf991.1498659915.git.jpoimboe@redhat.com> (raw)
In-Reply-To: <cover.1498659915.git.jpoimboe@redhat.com>

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

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 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 f3b1b27..465e5e2 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/undwarf.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
-- 
2.7.5
