1c2672b49a
The sh implementation of <asm/cmpxchg-xchg.h> pulls in <linux/bitops.h> so that it can refer to BITS_PER_BYTE. It also transitively relies on this pulling in <linux/compiler.h> for READ_ONCE(). Replace the #include with <linux/bits.h> and <linux/compiler.h>. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: yamada.masahiro@socionext.com Link: https://lore.kernel.org/lkml/1529412794-17720-6-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
53 lines
1.4 KiB
C
53 lines
1.4 KiB
C
#ifndef __ASM_SH_CMPXCHG_XCHG_H
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#define __ASM_SH_CMPXCHG_XCHG_H
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/*
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* Copyright (C) 2016 Red Hat, Inc.
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* Author: Michael S. Tsirkin <mst@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See the
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* file "COPYING" in the main directory of this archive for more details.
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*/
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#include <linux/bits.h>
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#include <linux/compiler.h>
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#include <asm/byteorder.h>
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/*
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* Portable implementations of 1 and 2 byte xchg using a 4 byte cmpxchg.
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* Note: this header isn't self-contained: before including it, __cmpxchg_u32
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* must be defined first.
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*/
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static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size)
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{
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int off = (unsigned long)ptr % sizeof(u32);
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volatile u32 *p = ptr - off;
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#ifdef __BIG_ENDIAN
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int bitoff = (sizeof(u32) - size - off) * BITS_PER_BYTE;
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#else
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int bitoff = off * BITS_PER_BYTE;
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#endif
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u32 bitmask = ((0x1 << size * BITS_PER_BYTE) - 1) << bitoff;
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u32 oldv, newv;
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u32 ret;
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do {
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oldv = READ_ONCE(*p);
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ret = (oldv & bitmask) >> bitoff;
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newv = (oldv & ~bitmask) | (x << bitoff);
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} while (__cmpxchg_u32(p, oldv, newv) != oldv);
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return ret;
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}
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static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val)
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{
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return __xchg_cmpxchg(m, val, sizeof *m);
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}
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static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
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{
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return __xchg_cmpxchg(m, val, sizeof *m);
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}
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#endif /* __ASM_SH_CMPXCHG_XCHG_H */
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