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Commit 3387a535 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
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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: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent 13523309

arch/x86/lib/rwsem.S

+10 −1
Original line number Diff line number Diff line
@@ -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)