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Subject[tip:x86/debug] x86/asm: Create stack frames in rwsem functions
Commit-ID:  3387a535ce629906d849864ef6a3c3437a645cb5
Gitweb: http://git.kernel.org/tip/3387a535ce629906d849864ef6a3c3437a645cb5
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Thu, 21 Jan 2016 16:49:22 -0600
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 24 Feb 2016 08:35:43 +0100

x86/asm: Create stack frames in rwsem functions

rwsem.S has several callable non-leaf functions which don't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces.

Create stack frames for them when CONFIG_FRAME_POINTER is enabled.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.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: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/ad0932bbead975b15f9578e4f2cf2ee5961eb840.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/lib/rwsem.S | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S
index 40027db..be110ef 100644
--- a/arch/x86/lib/rwsem.S
+++ b/arch/x86/lib/rwsem.S
@@ -15,6 +15,7 @@

#include <linux/linkage.h>
#include <asm/alternative-asm.h>
+#include <asm/frame.h>

#define __ASM_HALF_REG(reg) __ASM_SEL(reg, e##reg)
#define __ASM_HALF_SIZE(inst) __ASM_SEL(inst##w, inst##l)
@@ -84,24 +85,29 @@

/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
+ FRAME_BEGIN
save_common_regs
__ASM_SIZE(push,) %__ASM_REG(dx)
movq %rax,%rdi
call rwsem_down_read_failed
__ASM_SIZE(pop,) %__ASM_REG(dx)
restore_common_regs
+ FRAME_END
ret
ENDPROC(call_rwsem_down_read_failed)

ENTRY(call_rwsem_down_write_failed)
+ FRAME_BEGIN
save_common_regs
movq %rax,%rdi
call rwsem_down_write_failed
restore_common_regs
+ FRAME_END
ret
ENDPROC(call_rwsem_down_write_failed)

ENTRY(call_rwsem_wake)
+ FRAME_BEGIN
/* do nothing if still outstanding active readers */
__ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
jnz 1f
@@ -109,15 +115,18 @@ ENTRY(call_rwsem_wake)
movq %rax,%rdi
call rwsem_wake
restore_common_regs
-1: ret
+1: FRAME_END
+ ret
ENDPROC(call_rwsem_wake)

ENTRY(call_rwsem_downgrade_wake)
+ FRAME_BEGIN
save_common_regs
__ASM_SIZE(push,) %__ASM_REG(dx)
movq %rax,%rdi
call rwsem_downgrade_wake
__ASM_SIZE(pop,) %__ASM_REG(dx)
restore_common_regs
+ FRAME_END
ret
ENDPROC(call_rwsem_downgrade_wake)
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