| Thomas Petazzoni | 774400a | 2008-08-18 12:33:21 +0200 | [diff] [blame] | 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 |
| 10 | unsigned 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 | } |
| 23 | EXPORT_SYMBOL(cmpxchg_386_u8); |
| 24 | |
| 25 | unsigned 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 | } |
| 38 | EXPORT_SYMBOL(cmpxchg_386_u16); |
| 39 | |
| 40 | unsigned 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 | } |
| 53 | EXPORT_SYMBOL(cmpxchg_386_u32); |
| 54 | #endif |