x86: Generate cmpxchg build failures
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>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
63312b6a6f
commit
f3834b9ef6
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@ -8,14 +8,50 @@
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* you need to test for the feature in boot_cpu_data.
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*/
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#define xchg(ptr, v) \
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((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), sizeof(*(ptr))))
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extern void __xchg_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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struct __xchg_dummy {
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unsigned long a[100];
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};
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#define __xg(x) ((struct __xchg_dummy *)(x))
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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 %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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/*
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* The semantics of XCHGCMP8B are a bit strange, this is why
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* there is a loop and the loading of %%eax and %%edx has to
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@ -71,57 +107,63 @@ static inline void __set_64bit_var(unsigned long long *ptr,
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(unsigned int)((value) >> 32)) \
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: __set_64bit(ptr, ll_low((value)), ll_high((value))))
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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 %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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extern void __cmpxchg_wrong_size(void);
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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 %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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#ifdef CONFIG_X86_CMPXCHG
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#define __HAVE_ARCH_CMPXCHG 1
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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), \
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sizeof(*(ptr))))
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#define sync_cmpxchg(ptr, o, n) \
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((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
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(unsigned long)(n), \
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sizeof(*(ptr))))
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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 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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#endif
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#ifdef CONFIG_X86_CMPXCHG64
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@ -133,94 +175,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
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(unsigned long long)(n)))
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#endif
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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 %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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/*
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* Always use locked operations when touching memory shared with a
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* hypervisor, since the system may be SMP even if the guest kernel
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* isn't.
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*/
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static inline unsigned long __sync_cmpxchg(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("lock; 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; 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; cmpxchgl %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 %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 long __cmpxchg64(volatile void *ptr,
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unsigned long long old,
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unsigned long long new)
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@ -3,9 +3,6 @@
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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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@ -15,167 +12,118 @@ static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
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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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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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#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 __HAVE_ARCH_CMPXCHG 1
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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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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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#define __sync_cmpxchg(ptr, old, new, size) \
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__raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
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/*
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* Always use locked operations when touching memory shared with a
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* hypervisor, since the system may be SMP even if the guest kernel
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* isn't.
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*/
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static inline unsigned long __sync_cmpxchg(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("lock; 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; 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; cmpxchgl %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_local(ptr, old, new, size) \
|
||||
__raw_cmpxchg((ptr), (old), (new), (size), "")
|
||||
|
||||
static inline unsigned long __cmpxchg_local(volatile void *ptr,
|
||||
unsigned long old,
|
||||
unsigned long new, int size)
|
||||
{
|
||||
unsigned long prev;
|
||||
switch (size) {
|
||||
case 1:
|
||||
asm volatile("cmpxchgb %b1,%2"
|
||||
: "=a"(prev)
|
||||
: "q"(new), "m"(*__xg(ptr)), "0"(old)
|
||||
: "memory");
|
||||
return prev;
|
||||
case 2:
|
||||
asm volatile("cmpxchgw %w1,%2"
|
||||
: "=a"(prev)
|
||||
: "r"(new), "m"(*__xg(ptr)), "0"(old)
|
||||
: "memory");
|
||||
return prev;
|
||||
case 4:
|
||||
asm volatile("cmpxchgl %k1,%2"
|
||||
: "=a"(prev)
|
||||
: "r"(new), "m"(*__xg(ptr)), "0"(old)
|
||||
: "memory");
|
||||
return prev;
|
||||
case 8:
|
||||
asm volatile("cmpxchgq %1,%2"
|
||||
: "=a"(prev)
|
||||
: "r"(new), "m"(*__xg(ptr)), "0"(old)
|
||||
: "memory");
|
||||
return prev;
|
||||
}
|
||||
return old;
|
||||
}
|
||||
#define cmpxchg(ptr, old, new) \
|
||||
__cmpxchg((ptr), (old), (new), sizeof(*ptr))
|
||||
|
||||
#define sync_cmpxchg(ptr, old, new) \
|
||||
__sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
|
||||
|
||||
#define cmpxchg_local(ptr, old, new) \
|
||||
__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
|
||||
|
||||
#define cmpxchg(ptr, o, n) \
|
||||
((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
|
||||
(unsigned long)(n), sizeof(*(ptr))))
|
||||
#define cmpxchg64(ptr, o, n) \
|
||||
({ \
|
||||
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
|
||||
cmpxchg((ptr), (o), (n)); \
|
||||
})
|
||||
#define cmpxchg_local(ptr, o, n) \
|
||||
((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
|
||||
(unsigned long)(n), \
|
||||
sizeof(*(ptr))))
|
||||
#define sync_cmpxchg(ptr, o, n) \
|
||||
((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
|
||||
(unsigned long)(n), \
|
||||
sizeof(*(ptr))))
|
||||
|
||||
#define cmpxchg64_local(ptr, o, n) \
|
||||
({ \
|
||||
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
|
||||
|
|
|
|||
Loading…
Reference in New Issue