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linux-next/arch/x86/lib/semaphore_32.S
Jan Beulich 4625cd6379 x86: Unify rwlock assembly implementation
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>
2011-07-21 09:03:31 +02:00

81 lines
1.9 KiB
ArmAsm

/*
* i386 semaphore implementation.
*
* (C) Copyright 1999 Linus Torvalds
*
* Portions Copyright 1999 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
*/
#include <linux/linkage.h>
#include <asm/frame.h>
#include <asm/dwarf2.h>
/*
* The semaphore operations have a special calling sequence that
* allow us to do a simpler in-line version of them. These routines
* need to convert that sequence back into the C sequence when
* there is contention on the semaphore.
*
* %eax contains the semaphore pointer on entry. Save the C-clobbered
* registers (%eax, %edx and %ecx) except %eax whish is either a return
* value or just clobbered..
*/
.section .sched.text, "ax"
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
CFI_STARTPROC
pushl_cfi %ecx
CFI_REL_OFFSET ecx,0
pushl_cfi %edx
CFI_REL_OFFSET edx,0
call rwsem_down_read_failed
popl_cfi %edx
popl_cfi %ecx
ret
CFI_ENDPROC
ENDPROC(call_rwsem_down_read_failed)
ENTRY(call_rwsem_down_write_failed)
CFI_STARTPROC
pushl_cfi %ecx
CFI_REL_OFFSET ecx,0
calll rwsem_down_write_failed
popl_cfi %ecx
ret
CFI_ENDPROC
ENDPROC(call_rwsem_down_write_failed)
ENTRY(call_rwsem_wake)
CFI_STARTPROC
decw %dx /* do nothing if still outstanding active readers */
jnz 1f
pushl_cfi %ecx
CFI_REL_OFFSET ecx,0
call rwsem_wake
popl_cfi %ecx
1: ret
CFI_ENDPROC
ENDPROC(call_rwsem_wake)
/* Fix up special calling conventions */
ENTRY(call_rwsem_downgrade_wake)
CFI_STARTPROC
pushl_cfi %ecx
CFI_REL_OFFSET ecx,0
pushl_cfi %edx
CFI_REL_OFFSET edx,0
call rwsem_downgrade_wake
popl_cfi %edx
popl_cfi %ecx
ret
CFI_ENDPROC
ENDPROC(call_rwsem_downgrade_wake)