73 lines
1.5 KiB
C
73 lines
1.5 KiB
C
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/*
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* cmpxchg*() fallbacks for CPU not supporting these instructions
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*/
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/module.h>
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#ifndef CONFIG_X86_CMPXCHG
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unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)
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{
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u8 prev;
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unsigned long flags;
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/* Poor man's cmpxchg for 386. Unsuitable for SMP */
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local_irq_save(flags);
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prev = *(u8 *)ptr;
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if (prev == old)
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*(u8 *)ptr = new;
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local_irq_restore(flags);
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return prev;
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}
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EXPORT_SYMBOL(cmpxchg_386_u8);
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unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new)
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{
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u16 prev;
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unsigned long flags;
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/* Poor man's cmpxchg for 386. Unsuitable for SMP */
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local_irq_save(flags);
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prev = *(u16 *)ptr;
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if (prev == old)
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*(u16 *)ptr = new;
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local_irq_restore(flags);
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return prev;
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}
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EXPORT_SYMBOL(cmpxchg_386_u16);
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unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
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{
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u32 prev;
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unsigned long flags;
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/* Poor man's cmpxchg for 386. Unsuitable for SMP */
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local_irq_save(flags);
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prev = *(u32 *)ptr;
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if (prev == old)
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*(u32 *)ptr = new;
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local_irq_restore(flags);
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return prev;
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}
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EXPORT_SYMBOL(cmpxchg_386_u32);
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#endif
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#ifndef CONFIG_X86_CMPXCHG64
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unsigned long long cmpxchg_486_u64(volatile void *ptr, u64 old, u64 new)
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{
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u64 prev;
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unsigned long flags;
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/* Poor man's cmpxchg8b for 386 and 486. Unsuitable for SMP */
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local_irq_save(flags);
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prev = *(u64 *)ptr;
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if (prev == old)
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*(u64 *)ptr = new;
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local_irq_restore(flags);
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return prev;
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}
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EXPORT_SYMBOL(cmpxchg_486_u64);
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#endif
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