9e5228ce0b
Commit b4816afa39 ("Move the asm-generic/system.h xchg()
implementation to asm-generic/cmpxchg.h") introduced the concept of
asm/cmpxchg.h but the parisc arch never got one. Fork the cmpxchg
content out of the asm/atomic.h file to create one.
Some minor whitespace fixups were done on the block of code that created
the new file.
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
/*
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* forked from parisc asm/atomic.h which was:
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* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
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* Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
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*/
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#ifndef _ASM_PARISC_CMPXCHG_H_
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#define _ASM_PARISC_CMPXCHG_H_
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/* This should get optimized out since it's never called.
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** Or get a link error if xchg is used "wrong".
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*/
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extern void __xchg_called_with_bad_pointer(void);
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/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
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extern unsigned long __xchg8(char, char *);
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extern unsigned long __xchg32(int, int *);
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#ifdef CONFIG_64BIT
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extern unsigned long __xchg64(unsigned long, unsigned long *);
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#endif
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/* optimizer better get rid of switch since size is a constant */
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static inline unsigned long
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__xchg(unsigned long x, __volatile__ void *ptr, int size)
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{
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switch (size) {
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#ifdef CONFIG_64BIT
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case 8: return __xchg64(x, (unsigned long *) ptr);
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#endif
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case 4: return __xchg32((int) x, (int *) ptr);
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case 1: return __xchg8((char) x, (char *) ptr);
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}
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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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** REVISIT - Abandoned use of LDCW in xchg() for now:
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** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
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** o and while we are at it, could CONFIG_64BIT code use LDCD too?
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**
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** if (__builtin_constant_p(x) && (x == NULL))
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** if (((unsigned long)p & 0xf) == 0)
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** return __ldcw(p);
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*/
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#define xchg(ptr, x) \
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((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
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#define __HAVE_ARCH_CMPXCHG 1
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/* bug catcher for when unsupported size is used - won't link */
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extern void __cmpxchg_called_with_bad_pointer(void);
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/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
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extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
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unsigned int new_);
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extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr,
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unsigned long old, unsigned long new_);
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/* don't worry...optimizer will get rid of most of this */
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static inline unsigned long
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__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
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{
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switch (size) {
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#ifdef CONFIG_64BIT
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case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
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#endif
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case 4: return __cmpxchg_u32((unsigned int *)ptr,
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(unsigned int)old, (unsigned int)new_);
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}
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__cmpxchg_called_with_bad_pointer();
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return old;
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}
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#define cmpxchg(ptr, o, n) \
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({ \
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__typeof__(*(ptr)) _o_ = (o); \
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__typeof__(*(ptr)) _n_ = (n); \
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(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
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(unsigned long)_n_, sizeof(*(ptr))); \
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})
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#include <asm-generic/cmpxchg-local.h>
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static inline unsigned long __cmpxchg_local(volatile void *ptr,
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unsigned long old,
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unsigned long new_, int size)
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{
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switch (size) {
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#ifdef CONFIG_64BIT
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case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
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#endif
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case 4: return __cmpxchg_u32(ptr, old, new_);
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default:
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return __cmpxchg_local_generic(ptr, old, new_, size);
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}
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}
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/*
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* cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
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* them available.
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*/
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#define cmpxchg_local(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
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(unsigned long)(n), sizeof(*(ptr))))
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#ifdef CONFIG_64BIT
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#define cmpxchg64_local(ptr, o, n) \
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({ \
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BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
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cmpxchg_local((ptr), (o), (n)); \
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})
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#else
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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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#endif /* _ASM_PARISC_CMPXCHG_H_ */
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