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x86: Unify rwlock assembly implementation

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Rather than having two functionally identical implementations
for 32- and 64-bit configurations, extend the existing assembly
abstractions enough to fold the two rwlock implementations into
a shared one.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4E258DD7020000780004E3EA@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jan Beulich
2011-07-19 12:59:51 +01:00
committed by Ingo Molnar
parent dd2897bf0f
commit 4625cd6379
6 changed files with 56 additions and 90 deletions
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44
arch/x86/lib/rwlock.S Normal file
View File

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/* Slow paths of read/write spinlocks. */
#include <linux/linkage.h>
#include <asm/alternative-asm.h>
#include <asm/frame.h>
#include <asm/rwlock.h>
#ifdef CONFIG_X86_32
# define __lock_ptr eax
#else
# define __lock_ptr rdi
#endif
ENTRY(__write_lock_failed)
CFI_STARTPROC
FRAME
0: LOCK_PREFIX
addl $RW_LOCK_BIAS, (%__lock_ptr)
1: rep; nop
cmpl $RW_LOCK_BIAS, (%__lock_ptr)
jne 1b
LOCK_PREFIX
subl $RW_LOCK_BIAS, (%__lock_ptr)
jnz 0b
ENDFRAME
ret
CFI_ENDPROC
END(__write_lock_failed)
ENTRY(__read_lock_failed)
CFI_STARTPROC
FRAME
0: LOCK_PREFIX
incl (%__lock_ptr)
1: rep; nop
cmpl $1, (%__lock_ptr)
js 1b
LOCK_PREFIX
decl (%__lock_ptr)
js 0b
ENDFRAME
ret
CFI_ENDPROC
END(__read_lock_failed)