72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
/* include/asm-i386/rwlock.h
|
|
*
|
|
* Helpers used by both rw spinlocks and rw semaphores.
|
|
*
|
|
* Based in part on code from semaphore.h and
|
|
* spinlock.h Copyright 1996 Linus Torvalds.
|
|
*
|
|
* Copyright 1999 Red Hat, Inc.
|
|
*
|
|
* Written by Benjamin LaHaise.
|
|
*
|
|
* 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.
|
|
*/
|
|
#ifndef _ASM_I386_RWLOCK_H
|
|
#define _ASM_I386_RWLOCK_H
|
|
|
|
#define RW_LOCK_BIAS 0x01000000
|
|
#define RW_LOCK_BIAS_STR "0x01000000"
|
|
|
|
#define __build_read_lock_ptr(rw, helper) \
|
|
asm volatile(LOCK "subl $1,(%0)\n\t" \
|
|
"jns 1f\n" \
|
|
"call " helper "\n\t" \
|
|
"1:\n" \
|
|
::"a" (rw) : "memory")
|
|
|
|
#define __build_read_lock_const(rw, helper) \
|
|
asm volatile(LOCK "subl $1,%0\n\t" \
|
|
"jns 1f\n" \
|
|
"pushl %%eax\n\t" \
|
|
"leal %0,%%eax\n\t" \
|
|
"call " helper "\n\t" \
|
|
"popl %%eax\n\t" \
|
|
"1:\n" \
|
|
:"=m" (*(volatile int *)rw) : : "memory")
|
|
|
|
#define __build_read_lock(rw, helper) do { \
|
|
if (__builtin_constant_p(rw)) \
|
|
__build_read_lock_const(rw, helper); \
|
|
else \
|
|
__build_read_lock_ptr(rw, helper); \
|
|
} while (0)
|
|
|
|
#define __build_write_lock_ptr(rw, helper) \
|
|
asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
|
|
"jz 1f\n" \
|
|
"call " helper "\n\t" \
|
|
"1:\n" \
|
|
::"a" (rw) : "memory")
|
|
|
|
#define __build_write_lock_const(rw, helper) \
|
|
asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
|
|
"jz 1f\n" \
|
|
"pushl %%eax\n\t" \
|
|
"leal %0,%%eax\n\t" \
|
|
"call " helper "\n\t" \
|
|
"popl %%eax\n\t" \
|
|
"1:\n" \
|
|
:"=m" (*(volatile int *)rw) : : "memory")
|
|
|
|
#define __build_write_lock(rw, helper) do { \
|
|
if (__builtin_constant_p(rw)) \
|
|
__build_write_lock_const(rw, helper); \
|
|
else \
|
|
__build_write_lock_ptr(rw, helper); \
|
|
} while (0)
|
|
|
|
#endif
|