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x86: Unify rwsem assembly implementation

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Rather than having two functionally identical implementations
for 32- and 64-bit configurations, use the previously extended
assembly abstractions to fold the rwsem two 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/4E258DF3020000780004E3ED@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jan Beulich 2011-07-19 13:00:19 +01:00 committed by Ingo Molnar
parent 4625cd6379
commit a738669464
5 changed files with 62 additions and 100 deletions
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2
arch/um/sys-i386/Makefile
View file

@ -8,7 +8,7 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
obj-$(CONFIG_BINFMT_ELF) += elfcore.o
subarch-obj-y = lib/semaphore_32.o lib/string_32.o
subarch-obj-y = lib/rwsem.o lib/string_32.o
subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
subarch-obj-$(CONFIG_MODULES) += kernel/module.o

2
arch/um/sys-x86_64/Makefile
View file

@ -9,7 +9,7 @@ obj-y = bug.o bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
sysrq.o ksyms.o tls.o
subarch-obj-y = lib/csum-partial_64.o lib/memcpy_64.o lib/thunk_64.o \
lib/rwsem_64.o
lib/rwsem.o
subarch-obj-$(CONFIG_MODULES) += kernel/module.o
ldt-y = ../sys-i386/ldt.o

3
arch/x86/lib/Makefile
View file

@ -21,6 +21,7 @@ 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-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
obj-y += msr.o msr-reg.o msr-reg-export.o
@ -30,7 +31,6 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += atomic64_cx8_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += semaphore_32.o
lib-y += string_32.o
lib-y += cmpxchg.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
@ -43,6 +43,5 @@ else
lib-y += thunk_64.o clear_page_64.o copy_page_64.o
lib-y += memmove_64.o memset_64.o
lib-y += copy_user_64.o copy_user_nocache_64.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o
lib-y += cmpxchg16b_emu.o
endif

75
arch/x86/lib/rwsem_64.S → arch/x86/lib/rwsem.S
View file

@ -1,3 +1,50 @@
/*
* x86 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/alternative-asm.h>
#include <asm/dwarf2.h>
#define __ASM_HALF_REG(reg) __ASM_SEL(reg, e##reg)
#define __ASM_HALF_SIZE(inst) __ASM_SEL(inst##w, inst##l)
#ifdef CONFIG_X86_32
/*
* 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..
*/
#define save_common_regs \
pushl_cfi %ecx; CFI_REL_OFFSET ecx, 0
#define restore_common_regs \
popl_cfi %ecx; CFI_RESTORE ecx
/* Avoid uglifying the argument copying x86-64 needs to do. */
.macro movq src, dst
.endm
#else
/*
* x86-64 rwsem wrappers
*
@ -16,12 +63,6 @@
* but %rdi, %rsi, %rcx, %r8-r11 always need saving.
*/
#include <linux/linkage.h>
#include <asm/rwlock.h>
#include <asm/alternative-asm.h>
#include <asm/frame.h>
#include <asm/dwarf2.h>
#define save_common_regs \
pushq_cfi %rdi; CFI_REL_OFFSET rdi, 0; \
pushq_cfi %rsi; CFI_REL_OFFSET rsi, 0; \
@ -40,16 +81,18 @@
popq_cfi %rsi; CFI_RESTORE rsi; \
popq_cfi %rdi; CFI_RESTORE rdi
#endif
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
CFI_STARTPROC
save_common_regs
pushq_cfi %rdx
CFI_REL_OFFSET rdx, 0
__ASM_SIZE(push,_cfi) %__ASM_REG(dx)
CFI_REL_OFFSET __ASM_REG(dx), 0
movq %rax,%rdi
call rwsem_down_read_failed
popq_cfi %rdx
CFI_RESTORE rdx
__ASM_SIZE(pop,_cfi) %__ASM_REG(dx)
CFI_RESTORE __ASM_REG(dx)
restore_common_regs
ret
CFI_ENDPROC
@ -67,7 +110,8 @@ ENDPROC(call_rwsem_down_write_failed)
ENTRY(call_rwsem_wake)
CFI_STARTPROC
decl %edx /* do nothing if still outstanding active readers */
/* do nothing if still outstanding active readers */
__ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
jnz 1f
save_common_regs
movq %rax,%rdi
@ -77,16 +121,15 @@ ENTRY(call_rwsem_wake)
CFI_ENDPROC
ENDPROC(call_rwsem_wake)
/* Fix up special calling conventions */
ENTRY(call_rwsem_downgrade_wake)
CFI_STARTPROC
save_common_regs
pushq_cfi %rdx
CFI_REL_OFFSET rdx, 0
__ASM_SIZE(push,_cfi) %__ASM_REG(dx)
CFI_REL_OFFSET __ASM_REG(dx), 0
movq %rax,%rdi
call rwsem_downgrade_wake
popq_cfi %rdx
CFI_RESTORE rdx
__ASM_SIZE(pop,_cfi) %__ASM_REG(dx)
CFI_RESTORE __ASM_REG(dx)
restore_common_regs
ret
CFI_ENDPROC

80
arch/x86/lib/semaphore_32.S
View file

@ -1,80 +0,0 @@
/*
* 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)