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d428032b35
Add (and export) __cmpxchg_u16(), teach __cmpxchg() to use it. And get rid of manual truncation down to u8, etc. in there - the only reason for those is to avoid bogus warnings about constant truncation from sparse, and those are easy to avoid by turning that switch into conditional expression. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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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, volatile char *);
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extern unsigned long __xchg32(int, volatile int *);
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#ifdef CONFIG_64BIT
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extern unsigned long __xchg64(unsigned long, volatile 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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__arch_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, (volatile unsigned long *) ptr);
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#endif
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case 4: return __xchg32((int) x, (volatile int *) ptr);
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case 1: return __xchg8((char) x, (volatile 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 arch_xchg(ptr, x) \
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({ \
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__typeof__(*(ptr)) __ret; \
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__typeof__(*(ptr)) _x_ = (x); \
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__ret = (__typeof__(*(ptr))) \
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__arch_xchg((unsigned long)_x_, (ptr), sizeof(*(ptr))); \
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__ret; \
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})
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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_u... defined in arch/parisc/lib/bitops.c */
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extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
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extern u16 __cmpxchg_u16(volatile u16 *ptr, u16 old, u16 new_);
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extern u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
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extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 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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return
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#ifdef CONFIG_64BIT
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size == 8 ? __cmpxchg_u64(ptr, old, new_) :
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#endif
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size == 4 ? __cmpxchg_u32(ptr, old, new_) :
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size == 2 ? __cmpxchg_u16(ptr, old, new_) :
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size == 1 ? __cmpxchg_u8(ptr, old, new_) :
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(__cmpxchg_called_with_bad_pointer(), old);
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}
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#define arch_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((u64 *)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 __generic_cmpxchg_local(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 arch_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 arch_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 arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
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#endif
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#define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
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#endif /* _ASM_PARISC_CMPXCHG_H_ */
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