Файловый менеджер - Редактировать - /usr/src/linux-headers-5.4.0-200/arch/x86/include/asm/cmpxchg_32.h
Назад
/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_CMPXCHG_32_H #define _ASM_X86_CMPXCHG_32_H /* * Note: if you use set64_bit(), __cmpxchg64(), or their variants, you * you need to test for the feature in boot_cpu_data. */ /* * CMPXCHG8B only writes to the target if we had the previous * value in registers, otherwise it acts as a read and gives us the * "new previous" value. That is why there is a loop. Preloading * EDX:EAX is a performance optimization: in the common case it means * we need only one locked operation. * * A SIMD/3DNOW!/MMX/FPU 64-bit store here would require at the very * least an FPU save and/or %cr0.ts manipulation. * * cmpxchg8b must be used with the lock prefix here to allow the * instruction to be executed atomically. We need to have the reader * side to see the coherent 64bit value. */ static inline void set_64bit(volatile u64 *ptr, u64 value) { u32 low = value; u32 high = value >> 32; u64 prev = *ptr; asm volatile("\n1:\t" LOCK_PREFIX "cmpxchg8b %0\n\t" "jnz 1b" : "=m" (*ptr), "+A" (prev) : "b" (low), "c" (high) : "memory"); } #ifdef CONFIG_X86_CMPXCHG64 #define arch_cmpxchg64(ptr, o, n) \ ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \ (unsigned long long)(n))) #define arch_cmpxchg64_local(ptr, o, n) \ ((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \ (unsigned long long)(n))) #endif static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new) { u64 prev; asm volatile(LOCK_PREFIX "cmpxchg8b %1" : "=A" (prev), "+m" (*ptr) : "b" ((u32)new), "c" ((u32)(new >> 32)), "0" (old) : "memory"); return prev; } static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new) { u64 prev; asm volatile("cmpxchg8b %1" : "=A" (prev), "+m" (*ptr) : "b" ((u32)new), "c" ((u32)(new >> 32)), "0" (old) : "memory"); return prev; } #ifndef CONFIG_X86_CMPXCHG64 /* * Building a kernel capable running on 80386 and 80486. It may be necessary * to simulate the cmpxchg8b on the 80386 and 80486 CPU. */ #define arch_cmpxchg64(ptr, o, n) \ ({ \ __typeof__(*(ptr)) __ret; \ __typeof__(*(ptr)) __old = (o); \ __typeof__(*(ptr)) __new = (n); \ alternative_io(LOCK_PREFIX_HERE \ "call cmpxchg8b_emu", \ "lock; cmpxchg8b (%%esi)" , \ X86_FEATURE_CX8, \ "=A" (__ret), \ "S" ((ptr)), "0" (__old), \ "b" ((unsigned int)__new), \ "c" ((unsigned int)(__new>>32)) \ : "memory"); \ __ret; }) #define arch_cmpxchg64_local(ptr, o, n) \ ({ \ __typeof__(*(ptr)) __ret; \ __typeof__(*(ptr)) __old = (o); \ __typeof__(*(ptr)) __new = (n); \ alternative_io("call cmpxchg8b_emu", \ "cmpxchg8b (%%esi)" , \ X86_FEATURE_CX8, \ "=A" (__ret), \ "S" ((ptr)), "0" (__old), \ "b" ((unsigned int)__new), \ "c" ((unsigned int)(__new>>32)) \ : "memory"); \ __ret; }) #endif #define system_has_cmpxchg_double() boot_cpu_has(X86_FEATURE_CX8) #endif /* _ASM_X86_CMPXCHG_32_H */
| ver. 1.4 |
Github
|
.
| PHP 7.4.3-4ubuntu2.24 | Генерация страницы: 0 |
proxy
|
phpinfo
|
Настройка