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109 lines
2.2 KiB
109 lines
2.2 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Generic UP xchg and cmpxchg using interrupt disablement. Does not |
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* support SMP. |
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*/ |
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#ifndef __ASM_GENERIC_CMPXCHG_H |
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#define __ASM_GENERIC_CMPXCHG_H |
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#ifdef CONFIG_SMP |
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#error "Cannot use generic cmpxchg on SMP" |
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#endif |
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#include <linux/types.h> |
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#include <linux/irqflags.h> |
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#ifndef xchg |
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/* |
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* This function doesn't exist, so you'll get a linker error if |
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* something tries to do an invalidly-sized xchg(). |
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*/ |
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extern void __xchg_called_with_bad_pointer(void); |
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static inline |
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unsigned long __xchg(unsigned long x, volatile void *ptr, int size) |
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{ |
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unsigned long ret, flags; |
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switch (size) { |
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case 1: |
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#ifdef __xchg_u8 |
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return __xchg_u8(x, ptr); |
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#else |
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local_irq_save(flags); |
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ret = *(volatile u8 *)ptr; |
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*(volatile u8 *)ptr = x; |
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local_irq_restore(flags); |
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return ret; |
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#endif /* __xchg_u8 */ |
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case 2: |
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#ifdef __xchg_u16 |
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return __xchg_u16(x, ptr); |
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#else |
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local_irq_save(flags); |
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ret = *(volatile u16 *)ptr; |
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*(volatile u16 *)ptr = x; |
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local_irq_restore(flags); |
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return ret; |
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#endif /* __xchg_u16 */ |
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case 4: |
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#ifdef __xchg_u32 |
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return __xchg_u32(x, ptr); |
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#else |
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local_irq_save(flags); |
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ret = *(volatile u32 *)ptr; |
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*(volatile u32 *)ptr = x; |
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local_irq_restore(flags); |
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return ret; |
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#endif /* __xchg_u32 */ |
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#ifdef CONFIG_64BIT |
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case 8: |
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#ifdef __xchg_u64 |
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return __xchg_u64(x, ptr); |
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#else |
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local_irq_save(flags); |
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ret = *(volatile u64 *)ptr; |
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*(volatile u64 *)ptr = x; |
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local_irq_restore(flags); |
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return ret; |
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#endif /* __xchg_u64 */ |
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#endif /* CONFIG_64BIT */ |
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default: |
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__xchg_called_with_bad_pointer(); |
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return x; |
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} |
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} |
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#define xchg(ptr, x) ({ \ |
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((__typeof__(*(ptr))) \ |
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__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ |
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}) |
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#endif /* xchg */ |
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/* |
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* Atomic compare and exchange. |
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*/ |
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#include <asm-generic/cmpxchg-local.h> |
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#ifndef cmpxchg_local |
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#define cmpxchg_local(ptr, o, n) ({ \ |
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((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ |
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(unsigned long)(n), sizeof(*(ptr)))); \ |
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}) |
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#endif |
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#ifndef cmpxchg64_local |
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#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) |
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#endif |
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#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) |
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#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) |
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#endif /* __ASM_GENERIC_CMPXCHG_H */
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