forked from Minki/linux
f3834b9ef6
Rework the x86 cmpxchg() implementation to generate build failures when used on improper types. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1254771187.21044.22.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
#ifndef _ASM_X86_CMPXCHG_64_H
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#define _ASM_X86_CMPXCHG_64_H
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#include <asm/alternative.h> /* Provides LOCK_PREFIX */
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#define __xg(x) ((volatile long *)(x))
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static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
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{
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*ptr = val;
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}
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#define _set_64bit set_64bit
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extern void __xchg_wrong_size(void);
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extern void __cmpxchg_wrong_size(void);
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/*
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* Note: no "lock" prefix even on SMP: xchg always implies lock anyway
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* Note 2: xchg has side effect, so that attribute volatile is necessary,
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* but generally the primitive is invalid, *ptr is output argument. --ANK
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*/
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#define __xchg(x, ptr, size) \
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({ \
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__typeof(*(ptr)) __x = (x); \
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switch (size) { \
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case 1: \
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asm volatile("xchgb %b0,%1" \
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: "=q" (__x) \
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: "m" (*__xg(ptr)), "0" (__x) \
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: "memory"); \
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break; \
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case 2: \
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asm volatile("xchgw %w0,%1" \
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: "=r" (__x) \
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: "m" (*__xg(ptr)), "0" (__x) \
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: "memory"); \
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break; \
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case 4: \
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asm volatile("xchgl %k0,%1" \
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: "=r" (__x) \
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: "m" (*__xg(ptr)), "0" (__x) \
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: "memory"); \
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break; \
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case 8: \
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asm volatile("xchgq %0,%1" \
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: "=r" (__x) \
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: "m" (*__xg(ptr)), "0" (__x) \
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: "memory"); \
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break; \
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default: \
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__xchg_wrong_size(); \
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} \
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__x; \
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})
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#define xchg(ptr, v) \
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__xchg((v), (ptr), sizeof(*ptr))
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#define __HAVE_ARCH_CMPXCHG 1
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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 1: \
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asm volatile(lock "cmpxchgb %b1,%2" \
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: "=a"(__ret) \
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: "q"(__new), "m"(*__xg(ptr)), "0"(__old) \
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: "memory"); \
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break; \
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case 2: \
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asm volatile(lock "cmpxchgw %w1,%2" \
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: "=a"(__ret) \
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: "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
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: "memory"); \
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break; \
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case 4: \
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asm volatile(lock "cmpxchgl %k1,%2" \
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: "=a"(__ret) \
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: "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
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: "memory"); \
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break; \
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case 8: \
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asm volatile(lock "cmpxchgq %1,%2" \
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: "=a"(__ret) \
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: "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
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: "memory"); \
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break; \
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default: \
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__cmpxchg_wrong_size(); \
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} \
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__ret; \
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})
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#define __cmpxchg(ptr, old, new, size) \
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__raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
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#define __sync_cmpxchg(ptr, old, new, size) \
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__raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
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#define __cmpxchg_local(ptr, old, new, size) \
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__raw_cmpxchg((ptr), (old), (new), (size), "")
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#define cmpxchg(ptr, old, new) \
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__cmpxchg((ptr), (old), (new), sizeof(*ptr))
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#define sync_cmpxchg(ptr, old, new) \
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__sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
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#define cmpxchg_local(ptr, old, new) \
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__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
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#define cmpxchg64(ptr, o, n) \
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({ \
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BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
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cmpxchg((ptr), (o), (n)); \
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})
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#define cmpxchg64_local(ptr, o, n) \
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({ \
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BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
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cmpxchg_local((ptr), (o), (n)); \
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})
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#endif /* _ASM_X86_CMPXCHG_64_H */
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