diff options
Diffstat (limited to 'arch/parisc/include/asm/cmpxchg.h')
| -rw-r--r-- | arch/parisc/include/asm/cmpxchg.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/parisc/include/asm/cmpxchg.h b/arch/parisc/include/asm/cmpxchg.h new file mode 100644 index 000000000..5f274be10 --- /dev/null +++ b/arch/parisc/include/asm/cmpxchg.h @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * forked from parisc asm/atomic.h which was: + * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> + * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org> + */ + +#ifndef _ASM_PARISC_CMPXCHG_H_ +#define _ASM_PARISC_CMPXCHG_H_ + +/* This should get optimized out since it's never called. +** Or get a link error if xchg is used "wrong". +*/ +extern void __xchg_called_with_bad_pointer(void); + +/* __xchg32/64 defined in arch/parisc/lib/bitops.c */ +extern unsigned long __xchg8(char, volatile char *); +extern unsigned long __xchg32(int, volatile int *); +#ifdef CONFIG_64BIT +extern unsigned long __xchg64(unsigned long, volatile unsigned long *); +#endif + +/* optimizer better get rid of switch since size is a constant */ +static inline unsigned long +__xchg(unsigned long x, volatile void *ptr, int size) +{ + switch (size) { +#ifdef CONFIG_64BIT + case 8: return __xchg64(x, (volatile unsigned long *) ptr); +#endif + case 4: return __xchg32((int) x, (volatile int *) ptr); + case 1: return __xchg8((char) x, (volatile char *) ptr); + } + __xchg_called_with_bad_pointer(); + return x; +} + +/* +** REVISIT - Abandoned use of LDCW in xchg() for now: +** o need to test sizeof(*ptr) to avoid clearing adjacent bytes +** o and while we are at it, could CONFIG_64BIT code use LDCD too? +** +** if (__builtin_constant_p(x) && (x == NULL)) +** if (((unsigned long)p & 0xf) == 0) +** return __ldcw(p); +*/ +#define arch_xchg(ptr, x) \ +({ \ + __typeof__(*(ptr)) __ret; \ + __typeof__(*(ptr)) _x_ = (x); \ + __ret = (__typeof__(*(ptr))) \ + __xchg((unsigned long)_x_, (ptr), sizeof(*(ptr))); \ + __ret; \ +}) + +/* bug catcher for when unsupported size is used - won't link */ +extern void __cmpxchg_called_with_bad_pointer(void); + +/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */ +extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, + unsigned int new_); +extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_); +extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_); + +/* don't worry...optimizer will get rid of most of this */ +static inline unsigned long +__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) +{ + switch (size) { +#ifdef CONFIG_64BIT + case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); +#endif + case 4: return __cmpxchg_u32((unsigned int *)ptr, + (unsigned int)old, (unsigned int)new_); + case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff); + } + __cmpxchg_called_with_bad_pointer(); + return old; +} + +#define arch_cmpxchg(ptr, o, n) \ +({ \ + __typeof__(*(ptr)) _o_ = (o); \ + __typeof__(*(ptr)) _n_ = (n); \ + (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ + (unsigned long)_n_, sizeof(*(ptr))); \ +}) + +#include <asm-generic/cmpxchg-local.h> + +static inline unsigned long __cmpxchg_local(volatile void *ptr, + unsigned long old, + unsigned long new_, int size) +{ + switch (size) { +#ifdef CONFIG_64BIT + case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); +#endif + case 4: return __cmpxchg_u32(ptr, old, new_); + default: + return __generic_cmpxchg_local(ptr, old, new_, size); + } +} + +/* + * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make + * them available. + */ +#define arch_cmpxchg_local(ptr, o, n) \ + ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \ + (unsigned long)(n), sizeof(*(ptr)))) +#ifdef CONFIG_64BIT +#define arch_cmpxchg64_local(ptr, o, n) \ +({ \ + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ + cmpxchg_local((ptr), (o), (n)); \ +}) +#else +#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n)) +#endif + +#define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n) + +#endif /* _ASM_PARISC_CMPXCHG_H_ */ |