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Commit a7386694 authored by Jan Beulich's avatar Jan Beulich Committed by Ingo Molnar
Browse files

x86: Unify rwsem assembly implementation 



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: default avatarJan 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: default avatarIngo Molnar <mingo@elte.hu>
parent 4625cd63

arch/um/sys-i386/Makefile

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

arch/um/sys-x86_64/Makefile

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

arch/x86/lib/Makefile

+1 −2
Original line number Diff line number Diff line
@@ -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

arch/x86/lib/rwsem_64.S→arch/x86/lib/rwsem.S

+59 −16
Original line number Diff line number Diff line 
/*

 * 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

arch/x86/lib/semaphore_32.S

deleted100644 → 0
+0 −80
Original line number Diff line number Diff line 
/*

 * 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)