mirror of
https://github.com/checkpoint-restore/criu.git
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70833bcf29
Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Adrian Reber <areber@redhat.com>
93 lines
5 KiB
C
93 lines
5 KiB
C
#ifndef __CR_CMPXCHG_H__
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#define __CR_CMPXCHG_H__
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#include <stdint.h>
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#define LOCK_PREFIX "\n\tlock; "
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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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* An exchange-type operation, which takes a value and a pointer, and
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* returns the old value. Make sure you never reach non-case statement
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* here, otherwise behaviour is undefined.
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*/
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#define __xchg_op(ptr, arg, op, lock) \
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({ \
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__typeof__(*(ptr)) __ret = (arg); \
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switch (sizeof(*(ptr))) { \
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case __X86_CASE_B: \
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asm volatile(lock #op "b %b0, %1\n" : "+q"(__ret), "+m"(*(ptr)) : : "memory", "cc"); \
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break; \
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case __X86_CASE_W: \
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asm volatile(lock #op "w %w0, %1\n" : "+r"(__ret), "+m"(*(ptr)) : : "memory", "cc"); \
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break; \
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case __X86_CASE_L: \
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asm volatile(lock #op "l %0, %1\n" : "+r"(__ret), "+m"(*(ptr)) : : "memory", "cc"); \
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break; \
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case __X86_CASE_Q: \
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asm volatile(lock #op "q %q0, %1\n" : "+r"(__ret), "+m"(*(ptr)) : : "memory", "cc"); \
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break; \
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} \
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__ret; \
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})
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#define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock)
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#define xadd(ptr, inc) __xadd((ptr), (inc), "lock ;")
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/* Borrowed from linux kernel arch/x86/include/asm/cmpxchg.h */
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/*
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* Atomic compare and exchange. Compare OLD with MEM, if identical,
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* store NEW in MEM. Return the initial value in MEM. Success is
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* indicated by comparing RETURN with OLD.
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*/
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#define __raw_cmpxchg(ptr, old, new, size, lock) \
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({ \
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__typeof__(*(ptr)) __ret; \
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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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case __X86_CASE_B: { \
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volatile uint8_t *__ptr = (volatile uint8_t *)(ptr); \
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asm volatile(lock "cmpxchgb %2,%1" \
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: "=a"(__ret), "+m"(*__ptr) \
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: "q"(__new), "0"(__old) \
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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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volatile uint16_t *__ptr = (volatile uint16_t *)(ptr); \
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asm volatile(lock "cmpxchgw %2,%1" \
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: "=a"(__ret), "+m"(*__ptr) \
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: "r"(__new), "0"(__old) \
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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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volatile uint32_t *__ptr = (volatile uint32_t *)(ptr); \
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asm volatile(lock "cmpxchgl %2,%1" \
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: "=a"(__ret), "+m"(*__ptr) \
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: "r"(__new), "0"(__old) \
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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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volatile uint64_t *__ptr = (volatile uint64_t *)(ptr); \
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asm volatile(lock "cmpxchgq %2,%1" \
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: "=a"(__ret), "+m"(*__ptr) \
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: "r"(__new), "0"(__old) \
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: "memory"); \
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break; \
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} \
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} \
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__ret; \
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})
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#define __cmpxchg(ptr, old, new, size) __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
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#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, sizeof(*(ptr)))
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#endif /* __CR_CMPXCHG_H__ */
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