#include <linux/kernel.h>
#include <asm/segment.h>
#include <asm/cpufeature.h>
-#include <linux/bitops.h> /* for LOCK_PREFIX */
+#include <asm/cmpxchg.h>
#ifdef __KERNEL__
#define nop() __asm__ __volatile__ ("nop")
-#define xchg(ptr,v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr))))
-
-#define tas(ptr) (xchg((ptr),1))
-
-struct __xchg_dummy { unsigned long a[100]; };
-#define __xg(x) ((struct __xchg_dummy *)(x))
-
-
-#ifdef CONFIG_X86_CMPXCHG64
-
-/*
- * The semantics of XCHGCMP8B are a bit strange, this is why
- * there is a loop and the loading of %%eax and %%edx has to
- * be inside. This inlines well in most cases, the cached
- * cost is around ~38 cycles. (in the future we might want
- * to do an SIMD/3DNOW!/MMX/FPU 64-bit store here, but that
- * might have an implicit FPU-save as a cost, so it's not
- * clear which path to go.)
- *
- * cmpxchg8b must be used with the lock prefix here to allow
- * the instruction to be executed atomically, see page 3-102
- * of the instruction set reference 24319102.pdf. We need
- * the reader side to see the coherent 64bit value.
- */
-static inline void __set_64bit (unsigned long long * ptr,
- unsigned int low, unsigned int high)
-{
- __asm__ __volatile__ (
- "\n1:\t"
- "movl (%0), %%eax\n\t"
- "movl 4(%0), %%edx\n\t"
- "lock cmpxchg8b (%0)\n\t"
- "jnz 1b"
- : /* no outputs */
- : "D"(ptr),
- "b"(low),
- "c"(high)
- : "ax","dx","memory");
-}
-
-static inline void __set_64bit_constant (unsigned long long *ptr,
- unsigned long long value)
-{
- __set_64bit(ptr,(unsigned int)(value), (unsigned int)((value)>>32ULL));
-}
-#define ll_low(x) *(((unsigned int*)&(x))+0)
-#define ll_high(x) *(((unsigned int*)&(x))+1)
-
-static inline void __set_64bit_var (unsigned long long *ptr,
- unsigned long long value)
-{
- __set_64bit(ptr,ll_low(value), ll_high(value));
-}
-
-#define set_64bit(ptr,value) \
-(__builtin_constant_p(value) ? \
- __set_64bit_constant(ptr, value) : \
- __set_64bit_var(ptr, value) )
-
-#define _set_64bit(ptr,value) \
-(__builtin_constant_p(value) ? \
- __set_64bit(ptr, (unsigned int)(value), (unsigned int)((value)>>32ULL) ) : \
- __set_64bit(ptr, ll_low(value), ll_high(value)) )
-
-#endif
-
-/*
- * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
- * Note 2: xchg has side effect, so that attribute volatile is necessary,
- * but generally the primitive is invalid, *ptr is output argument. --ANK
- */
-static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
-{
- switch (size) {
- case 1:
- __asm__ __volatile__("xchgb %b0,%1"
- :"=q" (x)
- :"m" (*__xg(ptr)), "0" (x)
- :"memory");
- break;
- case 2:
- __asm__ __volatile__("xchgw %w0,%1"
- :"=r" (x)
- :"m" (*__xg(ptr)), "0" (x)
- :"memory");
- break;
- case 4:
- __asm__ __volatile__("xchgl %0,%1"
- :"=r" (x)
- :"m" (*__xg(ptr)), "0" (x)
- :"memory");
- break;
- }
- return x;
-}
-
-/*
- * Atomic compare and exchange. Compare OLD with MEM, if identical,
- * store NEW in MEM. Return the initial value in MEM. Success is
- * indicated by comparing RETURN with OLD.
- */
-
-#ifdef CONFIG_X86_CMPXCHG
-#define __HAVE_ARCH_CMPXCHG 1
-#define cmpxchg(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg((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))))
-#endif
-
-static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
- unsigned long new, int size)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- __asm__ __volatile__(LOCK_PREFIX "cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- __asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
-
-/*
- * Always use locked operations when touching memory shared with a
- * hypervisor, since the system may be SMP even if the guest kernel
- * isn't.
- */
-static inline unsigned long __sync_cmpxchg(volatile void *ptr,
- unsigned long old,
- unsigned long new, int size)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- __asm__ __volatile__("lock; cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- __asm__ __volatile__("lock; cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- __asm__ __volatile__("lock; cmpxchgl %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
-
-#ifndef CONFIG_X86_CMPXCHG
-/*
- * Building a kernel capable running on 80386. It may be necessary to
- * simulate the cmpxchg on the 80386 CPU. For that purpose we define
- * a function for each of the sizes we support.
- */
-
-extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
-extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
-extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
-
-static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
- unsigned long new, int size)
-{
- switch (size) {
- case 1:
- return cmpxchg_386_u8(ptr, old, new);
- case 2:
- return cmpxchg_386_u16(ptr, old, new);
- case 4:
- return cmpxchg_386_u32(ptr, old, new);
- }
- return old;
-}
-
-#define cmpxchg(ptr,o,n) \
-({ \
- __typeof__(*(ptr)) __ret; \
- if (likely(boot_cpu_data.x86 > 3)) \
- __ret = __cmpxchg((ptr), (unsigned long)(o), \
- (unsigned long)(n), sizeof(*(ptr))); \
- else \
- __ret = cmpxchg_386((ptr), (unsigned long)(o), \
- (unsigned long)(n), sizeof(*(ptr))); \
- __ret; \
-})
-#endif
-
-#ifdef CONFIG_X86_CMPXCHG64
-
-static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old,
- unsigned long long new)
-{
- unsigned long long prev;
- __asm__ __volatile__(LOCK_PREFIX "cmpxchg8b %3"
- : "=A"(prev)
- : "b"((unsigned long)new),
- "c"((unsigned long)(new >> 32)),
- "m"(*__xg(ptr)),
- "0"(old)
- : "memory");
- return prev;
-}
-
-#define cmpxchg64(ptr,o,n)\
- ((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\
- (unsigned long long)(n)))
-
-#endif
-
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
git.samba.org / sfrench / cifs-2.6.git / blobdiff