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Diffstat (limited to '')
| -rw-r--r-- | include/asm-generic/cmpxchg-local.h | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/include/asm-generic/cmpxchg-local.h b/include/asm-generic/cmpxchg-local.h new file mode 100644 index 000000000..f17f14f84 --- /dev/null +++ b/include/asm-generic/cmpxchg-local.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H +#define __ASM_GENERIC_CMPXCHG_LOCAL_H + +#include <linux/types.h> +#include <linux/irqflags.h> + +extern unsigned long wrong_size_cmpxchg(volatile void *ptr) + __noreturn; + +/* + * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned + * long parameter, supporting various types of architectures. + */ +static inline unsigned long __cmpxchg_local_generic(volatile void *ptr, + unsigned long old, unsigned long new, int size) +{ + unsigned long flags, prev; + + /* + * Sanity checking, compile-time. + */ + if (size == 8 && sizeof(unsigned long) != 8) + wrong_size_cmpxchg(ptr); + + raw_local_irq_save(flags); + switch (size) { + case 1: prev = *(u8 *)ptr; + if (prev == old) + *(u8 *)ptr = (u8)new; + break; + case 2: prev = *(u16 *)ptr; + if (prev == old) + *(u16 *)ptr = (u16)new; + break; + case 4: prev = *(u32 *)ptr; + if (prev == old) + *(u32 *)ptr = (u32)new; + break; + case 8: prev = *(u64 *)ptr; + if (prev == old) + *(u64 *)ptr = (u64)new; + break; + default: + wrong_size_cmpxchg(ptr); + } + raw_local_irq_restore(flags); + return prev; +} + +/* + * Generic version of __cmpxchg64_local. Takes an u64 parameter. + */ +static inline u64 __cmpxchg64_local_generic(volatile void *ptr, + u64 old, u64 new) +{ + u64 prev; + unsigned long flags; + + raw_local_irq_save(flags); + prev = *(u64 *)ptr; + if (prev == old) + *(u64 *)ptr = new; + raw_local_irq_restore(flags); + return prev; +} + +#endif |