149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
#ifndef __ASM_CMPXCHG_H
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#define __ASM_CMPXCHG_H
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#include <asm/alternative.h> /* Provides LOCK_PREFIX */
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#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), \
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(ptr), sizeof(*(ptr))))
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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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/*
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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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static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
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int size)
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{
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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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}
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return x;
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}
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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 __HAVE_ARCH_CMPXCHG 1
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static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
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unsigned long new, int size)
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{
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unsigned long prev;
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switch (size) {
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case 1:
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asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"
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: "=a"(prev)
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: "q"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 2:
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asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 4:
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asm volatile(LOCK_PREFIX "cmpxchgl %k1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 8:
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asm volatile(LOCK_PREFIX "cmpxchgq %1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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}
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return old;
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}
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static inline unsigned long __cmpxchg_local(volatile void *ptr,
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unsigned long old,
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unsigned long new, int size)
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{
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unsigned long prev;
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switch (size) {
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case 1:
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asm volatile("cmpxchgb %b1,%2"
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: "=a"(prev)
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: "q"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 2:
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asm volatile("cmpxchgw %w1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 4:
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asm volatile("cmpxchgl %k1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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case 8:
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asm volatile("cmpxchgq %1,%2"
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: "=a"(prev)
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: "r"(new), "m"(*__xg(ptr)), "0"(old)
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: "memory");
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return prev;
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}
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return old;
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}
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#define cmpxchg(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
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(unsigned long)(n), 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 cmpxchg_local(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
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(unsigned long)(n), \
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sizeof(*(ptr))))
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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
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