diff options
Diffstat (limited to 'arch/x86/include/asm/cmpxchg_64.h')
| -rw-r--r-- | arch/x86/include/asm/cmpxchg_64.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h new file mode 100644 index 000000000000..63c1a5e61b99 --- /dev/null +++ b/arch/x86/include/asm/cmpxchg_64.h @@ -0,0 +1,185 @@ +#ifndef ASM_X86__CMPXCHG_64_H +#define ASM_X86__CMPXCHG_64_H + +#include <asm/alternative.h> /* Provides LOCK_PREFIX */ + +#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), \ + (ptr), sizeof(*(ptr)))) + +#define __xg(x) ((volatile long *)(x)) + +static inline void set_64bit(volatile unsigned long *ptr, unsigned long val) +{ + *ptr = val; +} + +#define _set_64bit set_64bit + +/* + * 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 %k0,%1" + : "=r" (x) + : "m" (*__xg(ptr)), "0" (x) + : "memory"); + break; + case 8: + asm volatile("xchgq %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. + */ + +#define __HAVE_ARCH_CMPXCHG 1 + +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 %k1,%2" + : "=a"(prev) + : "r"(new), "m"(*__xg(ptr)), "0"(old) + : "memory"); + return prev; + case 8: + asm volatile(LOCK_PREFIX "cmpxchgq %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; +} + +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, 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); \ + cmpxchg_local((ptr), (o), (n)); \ +}) + +#endif /* ASM_X86__CMPXCHG_64_H */ |