mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-30 21:46:31 +00:00
d167a51877
Changes are largely identical to the i386 version: * alternative #define are moved to the new alternative.h file. * one new elf section with pointers to the lock prefixes which can be nop'ed out for non-smp. * two new elf sections simliar to the "classic" alternatives to replace SMP code with simpler UP code. * fixup headers to use alternative.h instead of defining their own LOCK / LOCK_PREFIX macros. The patch reuses the i386 version of the alternatives code to avoid code duplication. The code in alternatives.c was shuffled around a bit to reduce the number of #ifdefs needed. It also got some tweaks needed for x86_64 (vsyscall page handling) and new features (noreplacement option which was x86_64 only up to now). Debug printk's are changed from compile-time to runtime. Loosely based on a early version from Bastian Blank <waldi@debian.org> Signed-off-by: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
/* include/asm-x86_64/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.
|
|
* Copyright 2001,2002 SuSE labs
|
|
*
|
|
* 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_X86_64_RWLOCK_H
|
|
#define _ASM_X86_64_RWLOCK_H
|
|
|
|
#include <linux/stringify.h>
|
|
|
|
#define RW_LOCK_BIAS 0x01000000
|
|
#define RW_LOCK_BIAS_STR "0x01000000"
|
|
|
|
#define __build_read_lock_ptr(rw, helper) \
|
|
asm volatile(LOCK_PREFIX "subl $1,(%0)\n\t" \
|
|
"js 2f\n" \
|
|
"1:\n" \
|
|
LOCK_SECTION_START("") \
|
|
"2:\tcall " helper "\n\t" \
|
|
"jmp 1b\n" \
|
|
LOCK_SECTION_END \
|
|
::"a" (rw) : "memory")
|
|
|
|
#define __build_read_lock_const(rw, helper) \
|
|
asm volatile(LOCK_PREFIX "subl $1,%0\n\t" \
|
|
"js 2f\n" \
|
|
"1:\n" \
|
|
LOCK_SECTION_START("") \
|
|
"2:\tpushq %%rax\n\t" \
|
|
"leaq %0,%%rax\n\t" \
|
|
"call " helper "\n\t" \
|
|
"popq %%rax\n\t" \
|
|
"jmp 1b\n" \
|
|
LOCK_SECTION_END \
|
|
:"=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_PREFIX "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
|
|
"jnz 2f\n" \
|
|
"1:\n" \
|
|
LOCK_SECTION_START("") \
|
|
"2:\tcall " helper "\n\t" \
|
|
"jmp 1b\n" \
|
|
LOCK_SECTION_END \
|
|
::"a" (rw) : "memory")
|
|
|
|
#define __build_write_lock_const(rw, helper) \
|
|
asm volatile(LOCK_PREFIX "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
|
|
"jnz 2f\n" \
|
|
"1:\n" \
|
|
LOCK_SECTION_START("") \
|
|
"2:\tpushq %%rax\n\t" \
|
|
"leaq %0,%%rax\n\t" \
|
|
"call " helper "\n\t" \
|
|
"popq %%rax\n\t" \
|
|
"jmp 1b\n" \
|
|
LOCK_SECTION_END \
|
|
:"=m" (*((volatile long *)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
|