From 871480933a1c28f8a9fed4c4d34d06c439a7a422 Mon Sep 17 00:00:00 2001 From: Srikant Patnaik Date: Sun, 11 Jan 2015 12:28:04 +0530 Subject: Moved, renamed, and deleted files The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure. --- include/asm-generic/cmpxchg.h | 98 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 include/asm-generic/cmpxchg.h (limited to 'include/asm-generic/cmpxchg.h') diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h new file mode 100644 index 00000000..14883026 --- /dev/null +++ b/include/asm-generic/cmpxchg.h @@ -0,0 +1,98 @@ +/* + * Generic UP xchg and cmpxchg using interrupt disablement. Does not + * support SMP. + */ + +#ifndef __ASM_GENERIC_CMPXCHG_H +#define __ASM_GENERIC_CMPXCHG_H + +#ifdef CONFIG_SMP +#error "Cannot use generic cmpxchg on SMP" +#endif + +#include +#include + +#ifndef xchg + +/* + * This function doesn't exist, so you'll get a linker error if + * something tries to do an invalidly-sized xchg(). + */ +extern void __xchg_called_with_bad_pointer(void); + +static inline +unsigned long __xchg(unsigned long x, volatile void *ptr, int size) +{ + unsigned long ret, flags; + + switch (size) { + case 1: +#ifdef __xchg_u8 + return __xchg_u8(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u8 *)ptr; + *(volatile u8 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u8 */ + + case 2: +#ifdef __xchg_u16 + return __xchg_u16(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u16 *)ptr; + *(volatile u16 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u16 */ + + case 4: +#ifdef __xchg_u32 + return __xchg_u32(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u32 *)ptr; + *(volatile u32 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u32 */ + +#ifdef CONFIG_64BIT + case 8: +#ifdef __xchg_u64 + return __xchg_u64(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u64 *)ptr; + *(volatile u64 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u64 */ +#endif /* CONFIG_64BIT */ + + default: + __xchg_called_with_bad_pointer(); + return x; + } +} + +#define xchg(ptr, x) \ + ((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) + +#endif /* xchg */ + +/* + * Atomic compare and exchange. + * + * Do not define __HAVE_ARCH_CMPXCHG because we want to use it to check whether + * a cmpxchg primitive faster than repeated local irq save/restore exists. + */ +#include + +#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) +#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) + +#endif /* __ASM_GENERIC_CMPXCHG_H */ -- cgit