1/* 2 * cmpxchg*() fallbacks for CPU not supporting these instructions 3 */ 4 5#include <linux/kernel.h> 6#include <linux/smp.h> 7#include <linux/module.h> 8 9#ifndef CONFIG_X86_CMPXCHG 10unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new) 11{ 12 u8 prev; 13 unsigned long flags; 14 15 /* Poor man's cmpxchg for 386. Unsuitable for SMP */ 16 local_irq_save(flags); 17 prev = *(u8 *)ptr; 18 if (prev == old) 19 *(u8 *)ptr = new; 20 local_irq_restore(flags); 21 return prev; 22} 23EXPORT_SYMBOL(cmpxchg_386_u8); 24 25unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new) 26{ 27 u16 prev; 28 unsigned long flags; 29 30 /* Poor man's cmpxchg for 386. Unsuitable for SMP */ 31 local_irq_save(flags); 32 prev = *(u16 *)ptr; 33 if (prev == old) 34 *(u16 *)ptr = new; 35 local_irq_restore(flags); 36 return prev; 37} 38EXPORT_SYMBOL(cmpxchg_386_u16); 39 40unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new) 41{ 42 u32 prev; 43 unsigned long flags; 44 45 /* Poor man's cmpxchg for 386. Unsuitable for SMP */ 46 local_irq_save(flags); 47 prev = *(u32 *)ptr; 48 if (prev == old) 49 *(u32 *)ptr = new; 50 local_irq_restore(flags); 51 return prev; 52} 53EXPORT_SYMBOL(cmpxchg_386_u32); 54#endif 55