157 lines
3.7 KiB
ArmAsm
157 lines
3.7 KiB
ArmAsm
|
/*
|
||
|
|
* 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/frame.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 which is either a return
|
||
|
|
* value or just gets clobbered. Same is true for %edx so make sure GCC
|
||
|
|
* reloads it after the slow path, by making it hold a temporary, for
|
||
|
|
* example see ____down_write().
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define save_common_regs \
|
||
|
|
pushl %ecx
|
||
|
|
|
||
|
|
#define restore_common_regs \
|
||
|
|
popl %ecx
|
||
|
|
|
||
|
|
/* Avoid uglifying the argument copying x86-64 needs to do. */
|
||
|
|
.macro movq src, dst
|
||
|
|
.endm
|
||
|
|
|
||
|
|
#else
|
||
|
|
|
||
|
|
/*
|
||
|
|
* x86-64 rwsem wrappers
|
||
|
|
*
|
||
|
|
* This interfaces the inline asm code to the slow-path
|
||
|
|
* C routines. We need to save the call-clobbered regs
|
||
|
|
* that the asm does not mark as clobbered, and move the
|
||
|
|
* argument from %rax to %rdi.
|
||
|
|
*
|
||
|
|
* NOTE! We don't need to save %rax, because the functions
|
||
|
|
* will always return the semaphore pointer in %rax (which
|
||
|
|
* is also the input argument to these helpers)
|
||
|
|
*
|
||
|
|
* The following can clobber %rdx because the asm clobbers it:
|
||
|
|
* call_rwsem_down_write_failed
|
||
|
|
* call_rwsem_wake
|
||
|
|
* but %rdi, %rsi, %rcx, %r8-r11 always need saving.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define save_common_regs \
|
||
|
|
pushq %rdi; \
|
||
|
|
pushq %rsi; \
|
||
|
|
pushq %rcx; \
|
||
|
|
pushq %r8; \
|
||
|
|
pushq %r9; \
|
||
|
|
pushq %r10; \
|
||
|
|
pushq %r11
|
||
|
|
|
||
|
|
#define restore_common_regs \
|
||
|
|
popq %r11; \
|
||
|
|
popq %r10; \
|
||
|
|
popq %r9; \
|
||
|
|
popq %r8; \
|
||
|
|
popq %rcx; \
|
||
|
|
popq %rsi; \
|
||
|
|
popq %rdi
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* Fix up special calling conventions */
|
||
|
|
ENTRY(call_rwsem_down_read_failed)
|
||
|
|
FRAME_BEGIN
|
||
|
|
save_common_regs
|
||
|
|
__ASM_SIZE(push,) %__ASM_REG(dx)
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_down_read_failed
|
||
|
|
__ASM_SIZE(pop,) %__ASM_REG(dx)
|
||
|
|
restore_common_regs
|
||
|
|
FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_down_read_failed)
|
||
|
|
|
||
|
|
ENTRY(call_rwsem_down_read_failed_killable)
|
||
|
|
FRAME_BEGIN
|
||
|
|
save_common_regs
|
||
|
|
__ASM_SIZE(push,) %__ASM_REG(dx)
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_down_read_failed_killable
|
||
|
|
__ASM_SIZE(pop,) %__ASM_REG(dx)
|
||
|
|
restore_common_regs
|
||
|
|
FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_down_read_failed_killable)
|
||
|
|
|
||
|
|
ENTRY(call_rwsem_down_write_failed)
|
||
|
|
FRAME_BEGIN
|
||
|
|
save_common_regs
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_down_write_failed
|
||
|
|
restore_common_regs
|
||
|
|
FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_down_write_failed)
|
||
|
|
|
||
|
|
ENTRY(call_rwsem_down_write_failed_killable)
|
||
|
|
FRAME_BEGIN
|
||
|
|
save_common_regs
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_down_write_failed_killable
|
||
|
|
restore_common_regs
|
||
|
|
FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_down_write_failed_killable)
|
||
|
|
|
||
|
|
ENTRY(call_rwsem_wake)
|
||
|
|
FRAME_BEGIN
|
||
|
|
/* do nothing if still outstanding active readers */
|
||
|
|
__ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
|
||
|
|
jnz 1f
|
||
|
|
save_common_regs
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_wake
|
||
|
|
restore_common_regs
|
||
|
|
1: FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_wake)
|
||
|
|
|
||
|
|
ENTRY(call_rwsem_downgrade_wake)
|
||
|
|
FRAME_BEGIN
|
||
|
|
save_common_regs
|
||
|
|
__ASM_SIZE(push,) %__ASM_REG(dx)
|
||
|
|
movq %rax,%rdi
|
||
|
|
call rwsem_downgrade_wake
|
||
|
|
__ASM_SIZE(pop,) %__ASM_REG(dx)
|
||
|
|
restore_common_regs
|
||
|
|
FRAME_END
|
||
|
|
ret
|
||
|
|
ENDPROC(call_rwsem_downgrade_wake)
|