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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/sh/include/asm/cmpxchg-xchg.h | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/sh/include/asm/cmpxchg-xchg.h')
-rw-r--r-- | arch/sh/include/asm/cmpxchg-xchg.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/sh/include/asm/cmpxchg-xchg.h b/arch/sh/include/asm/cmpxchg-xchg.h new file mode 100644 index 0000000000..c373f21efe --- /dev/null +++ b/arch/sh/include/asm/cmpxchg-xchg.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_SH_CMPXCHG_XCHG_H +#define __ASM_SH_CMPXCHG_XCHG_H + +/* + * Copyright (C) 2016 Red Hat, Inc. + * Author: Michael S. Tsirkin <mst@redhat.com> + */ +#include <linux/bits.h> +#include <linux/compiler.h> +#include <asm/byteorder.h> + +/* + * Portable implementations of 1 and 2 byte xchg using a 4 byte cmpxchg. + * Note: this header isn't self-contained: before including it, __cmpxchg_u32 + * must be defined first. + */ +static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size) +{ + int off = (unsigned long)ptr % sizeof(u32); + volatile u32 *p = ptr - off; +#ifdef __BIG_ENDIAN + int bitoff = (sizeof(u32) - size - off) * BITS_PER_BYTE; +#else + int bitoff = off * BITS_PER_BYTE; +#endif + u32 bitmask = ((0x1 << size * BITS_PER_BYTE) - 1) << bitoff; + u32 oldv, newv; + u32 ret; + + do { + oldv = READ_ONCE(*p); + ret = (oldv & bitmask) >> bitoff; + newv = (oldv & ~bitmask) | (x << bitoff); + } while (__cmpxchg_u32(p, oldv, newv) != oldv); + + return ret; +} + +static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val) +{ + return __xchg_cmpxchg(m, val, sizeof *m); +} + +static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) +{ + return __xchg_cmpxchg(m, val, sizeof *m); +} + +#endif /* __ASM_SH_CMPXCHG_XCHG_H */ |