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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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3
arch/x86/include/asm/asm.h
View file

@ -15,7 +15,8 @@
# define __ASM_SEL(a,b) __ASM_FORM(b)
#endif
#define __ASM_SIZE(inst) __ASM_SEL(inst##l, inst##q)
#define __ASM_SIZE(inst, ...) __ASM_SEL(inst##l##__VA_ARGS__, \
inst##q##__VA_ARGS__)
#define __ASM_REG(reg) __ASM_SEL(e##reg, r##reg)
#define _ASM_PTR __ASM_SEL(.long, .quad)

11
arch/x86/include/asm/frame.h
View file

@ -1,5 +1,6 @@
#ifdef __ASSEMBLY__
#include <asm/asm.h>
#include <asm/dwarf2.h>
/* The annotation hides the frame from the unwinder and makes it look
@ -7,13 +8,13 @@
frame pointer later */
#ifdef CONFIG_FRAME_POINTER
.macro FRAME
pushl_cfi %ebp
CFI_REL_OFFSET ebp,0
movl %esp,%ebp
__ASM_SIZE(push,_cfi) %__ASM_REG(bp)
CFI_REL_OFFSET __ASM_REG(bp), 0
__ASM_SIZE(mov) %__ASM_REG(sp), %__ASM_REG(bp)
.endm
.macro ENDFRAME
popl_cfi %ebp
CFI_RESTORE ebp
__ASM_SIZE(pop,_cfi) %__ASM_REG(bp)
CFI_RESTORE __ASM_REG(bp)
.endm
#else
.macro FRAME

6
arch/x86/lib/Makefile
View file

@ -20,6 +20,7 @@ lib-y := delay.o
lib-y += thunk_$(BITS).o
lib-y += usercopy_$(BITS).o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
lib-$(CONFIG_SMP) += rwlock.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
obj-y += msr.o msr-reg.o msr-reg-export.o
@ -29,7 +30,8 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += atomic64_cx8_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
lib-y += semaphore_32.o string_32.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += semaphore_32.o
lib-y += string_32.o
lib-y += cmpxchg.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
lib-y += cmpxchg8b_emu.o atomic64_386_32.o
@ -40,7 +42,7 @@ else
lib-y += csum-partial_64.o csum-copy_64.o csum-wrappers_64.o
lib-y += thunk_64.o clear_page_64.o copy_page_64.o
lib-y += memmove_64.o memset_64.o
lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o
lib-y += copy_user_64.o copy_user_nocache_64.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o
lib-y += cmpxchg16b_emu.o
endif

44
arch/x86/lib/rwlock.S Normal file
View file

@ -0,0 +1,44 @@
/* 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)

38
arch/x86/lib/rwlock_64.S
View file

@ -1,38 +0,0 @@
/* Slow paths of read/write spinlocks. */
#include <linux/linkage.h>
#include <asm/rwlock.h>
#include <asm/alternative-asm.h>
#include <asm/dwarf2.h>
/* rdi: pointer to rwlock_t */
ENTRY(__write_lock_failed)
CFI_STARTPROC
LOCK_PREFIX
addl $RW_LOCK_BIAS,(%rdi)
1: rep
nop
cmpl $RW_LOCK_BIAS,(%rdi)
jne 1b
LOCK_PREFIX
subl $RW_LOCK_BIAS,(%rdi)
jnz __write_lock_failed
ret
CFI_ENDPROC
END(__write_lock_failed)
/* rdi: pointer to rwlock_t */
ENTRY(__read_lock_failed)
CFI_STARTPROC
LOCK_PREFIX
incl (%rdi)
1: rep
nop
cmpl $1,(%rdi)
js 1b
LOCK_PREFIX
decl (%rdi)
js __read_lock_failed
ret
CFI_ENDPROC
END(__read_lock_failed)

44
arch/x86/lib/semaphore_32.S
View file

@ -14,8 +14,6 @@
*/
#include <linux/linkage.h>
#include <asm/rwlock.h>
#include <asm/alternative-asm.h>
#include <asm/frame.h>
#include <asm/dwarf2.h>
@ -31,46 +29,6 @@
*/
.section .sched.text, "ax"
/*
* rw spinlock fallbacks
*/
#ifdef CONFIG_SMP
ENTRY(__write_lock_failed)
CFI_STARTPROC
FRAME
2: LOCK_PREFIX
addl $ RW_LOCK_BIAS,(%eax)
1: rep; nop
cmpl $ RW_LOCK_BIAS,(%eax)
jne 1b
LOCK_PREFIX
subl $ RW_LOCK_BIAS,(%eax)
jnz 2b
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__write_lock_failed)
ENTRY(__read_lock_failed)
CFI_STARTPROC
FRAME
2: LOCK_PREFIX
incl (%eax)
1: rep; nop
cmpl $1,(%eax)
js 1b
LOCK_PREFIX
decl (%eax)
js 2b
ENDFRAME
ret
CFI_ENDPROC
ENDPROC(__read_lock_failed)
#endif
#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
CFI_STARTPROC
@ -120,5 +78,3 @@ ENTRY(call_rwsem_downgrade_wake)
ret
CFI_ENDPROC
ENDPROC(call_rwsem_downgrade_wake)
#endif