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82 lines
4.7 KiB
C
82 lines
4.7 KiB
C
#pragma once
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#include <common/compiler.h>
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#include <arch/x86_64/asm/asm.h>
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/**
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* @brief 通过extern不存在的函数，来让编译器报错。以防止不符合要求的代码的产生。
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*/
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extern void __cmpxchg_wrong_size(void) __compiletime_error("Bad argument size for cmpxchg");
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// 定义常量：操作符涉及到的字节数
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#define __X86_CASE_B 1
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#define __X86_CASE_W 2
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#define __X86_CASE_L 4
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#define __X86_CASE_Q 8
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/**
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* @brief lock cmpxchg指令的包装。
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* 将_ptr指向的值与old_ptr指向的值做比较，如果相等，则将_new指向的值，加载到_ptr指向的值中。
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*/
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#define __raw_try_cmpxchg(_ptr, _old_ptr, _new, size) \
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({ \
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bool is_success = false; \
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typeof(_ptr) _old = (typeof(_ptr))(_old_ptr); \
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typeof(*(_ptr)) __old = *_old; \
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typeof(*(_ptr)) __new = (_new); \
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switch (size) \
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{ \
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case __X86_CASE_B: \
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{ \
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volatile uint8_t *__ptr = (volatile uint8_t *)(_ptr); \
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asm volatile("lock cmpxchgb %[new], %[ptr]\n\t" \
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: CC_OUT(z)(is_success), \
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[ptr] "+m"(*__ptr), \
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[old] "+a"(__old) \
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: [new] "q"(__new) \
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: "memory"); \
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break; \
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} \
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case __X86_CASE_W: \
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{ \
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volatile uint16_t *__ptr = (volatile uint16_t *)(_ptr); \
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asm volatile("lock cmpxchgw %[new], %[ptr]\n\t" \
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: CC_OUT(z)(is_success), \
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[ptr] "+m"(*__ptr), \
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[old] "+a"(__old) \
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: [new] "q"(__new) \
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: "memory"); \
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break; \
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} \
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case __X86_CASE_L: \
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{ \
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volatile uint32_t *__ptr = (volatile uint32_t *)(_ptr); \
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asm volatile("lock cmpxchgl %[new], %[ptr]\n\t" \
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: CC_OUT(z)(is_success), \
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[ptr] "+m"(*__ptr), \
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[old] "+a"(__old) \
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: [new] "q"(__new) \
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: "memory"); \
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break; \
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} \
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case __X86_CASE_Q: \
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{ \
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volatile uint64_t *__ptr = (volatile uint64_t *)(_ptr); \
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asm volatile("lock cmpxchgq %[new], %[ptr]\n\t" \
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: CC_OUT(z)(is_success), \
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[ptr] "+m"(*__ptr), \
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[old] "+a"(__old) \
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: [new] "q"(__new) \
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: "memory"); \
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break; \
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} \
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default: \
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__cmpxchg_wrong_size(); \
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} \
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if (unlikely(is_success == false)) \
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*_old = __old; \
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likely(is_success); \
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})
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#define arch_try_cmpxchg(ptr, old_ptr, new_ptr) \
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__raw_try_cmpxchg((ptr), (old_ptr), (new_ptr), sizeof(*ptr))
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