diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/sync_bitops.h | 156 | ||||
| -rw-r--r-- | include/asm-i386/system.h | 36 |
2 files changed, 192 insertions, 0 deletions
diff --git a/include/asm-i386/sync_bitops.h b/include/asm-i386/sync_bitops.h new file mode 100644 index 00000000000..c94d51c993e --- /dev/null +++ b/include/asm-i386/sync_bitops.h @@ -0,0 +1,156 @@ +#ifndef _I386_SYNC_BITOPS_H +#define _I386_SYNC_BITOPS_H + +/* + * Copyright 1992, Linus Torvalds. + */ + +/* + * These have to be done with inline assembly: that way the bit-setting + * is guaranteed to be atomic. All bit operations return 0 if the bit + * was cleared before the operation and != 0 if it was not. + * + * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). + */ + +#define ADDR (*(volatile long *) addr) + +/** + * sync_set_bit - Atomically set a bit in memory + * @nr: the bit to set + * @addr: the address to start counting from + * + * This function is atomic and may not be reordered. See __set_bit() + * if you do not require the atomic guarantees. + * + * Note: there are no guarantees that this function will not be reordered + * on non x86 architectures, so if you are writting portable code, + * make sure not to rely on its reordering guarantees. + * + * Note that @nr may be almost arbitrarily large; this function is not + * restricted to acting on a single-word quantity. + */ +static inline void sync_set_bit(int nr, volatile unsigned long * addr) +{ + __asm__ __volatile__("lock; btsl %1,%0" + :"+m" (ADDR) + :"Ir" (nr) + : "memory"); +} + +/** + * sync_clear_bit - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * sync_clear_bit() is atomic and may not be reordered. However, it does + * not contain a memory barrier, so if it is used for locking purposes, + * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() + * in order to ensure changes are visible on other processors. + */ +static inline void sync_clear_bit(int nr, volatile unsigned long * addr) +{ + __asm__ __volatile__("lock; btrl %1,%0" + :"+m" (ADDR) + :"Ir" (nr) + : "memory"); +} + +/** + * sync_change_bit - Toggle a bit in memory + * @nr: Bit to change + * @addr: Address to start counting from + * + * change_bit() is atomic and may not be reordered. It may be + * reordered on other architectures than x86. + * Note that @nr may be almost arbitrarily large; this function is not + * restricted to acting on a single-word quantity. + */ +static inline void sync_change_bit(int nr, volatile unsigned long * addr) +{ + __asm__ __volatile__("lock; btcl %1,%0" + :"+m" (ADDR) + :"Ir" (nr) + : "memory"); +} + +/** + * sync_test_and_set_bit - Set a bit and return its old value + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is atomic and cannot be reordered. + * It may be reordered on other architectures than x86. + * It also implies a memory barrier. + */ +static inline int sync_test_and_set_bit(int nr, volatile unsigned long * addr) +{ + int oldbit; + + __asm__ __volatile__("lock; btsl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"+m" (ADDR) + :"Ir" (nr) : "memory"); + return oldbit; +} + +/** + * sync_test_and_clear_bit - Clear a bit and return its old value + * @nr: Bit to clear + * @addr: Address to count from + * + * This operation is atomic and cannot be reordered. + * It can be reorderdered on other architectures other than x86. + * It also implies a memory barrier. + */ +static inline int sync_test_and_clear_bit(int nr, volatile unsigned long * addr) +{ + int oldbit; + + __asm__ __volatile__("lock; btrl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"+m" (ADDR) + :"Ir" (nr) : "memory"); + return oldbit; +} + +/** + * sync_test_and_change_bit - Change a bit and return its old value + * @nr: Bit to change + * @addr: Address to count from + * + * This operation is atomic and cannot be reordered. + * It also implies a memory barrier. + */ +static inline int sync_test_and_change_bit(int nr, volatile unsigned long* addr) +{ + int oldbit; + + __asm__ __volatile__("lock; btcl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"+m" (ADDR) + :"Ir" (nr) : "memory"); + return oldbit; +} + +static __always_inline int sync_const_test_bit(int nr, const volatile unsigned long *addr) +{ + return ((1UL << (nr & 31)) & + (((const volatile unsigned int *)addr)[nr >> 5])) != 0; +} + +static inline int sync_var_test_bit(int nr, const volatile unsigned long * addr) +{ + int oldbit; + + __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit) + :"m" (ADDR),"Ir" (nr)); + return oldbit; +} + +#define sync_test_bit(nr,addr) \ + (__builtin_constant_p(nr) ? \ + sync_constant_test_bit((nr),(addr)) : \ + sync_var_test_bit((nr),(addr))) + +#undef ADDR + +#endif /* _I386_SYNC_BITOPS_H */ diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index 098bcee94e3..a6dabbcd6e6 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -267,6 +267,9 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz #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, @@ -296,6 +299,39 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 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 |