cregit-Linux how code gets into the kernel

Release 4.8 arch/sh/include/asm/cmpxchg-xchg.h

#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>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See the
 * file "COPYING" in the main directory of this archive for more details.
 */
#include <linux/bitops.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; }

Contributors

PersonTokensPropCommitsCommitProp
michael s. tsirkinmichael s. tsirkin14899.33%150.00%
pan xinhuipan xinhui10.67%150.00%
Total149100.00%2100.00%


static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val) { return __xchg_cmpxchg(m, val, sizeof *m); }

Contributors

PersonTokensPropCommitsCommitProp
michael s. tsirkinmichael s. tsirkin29100.00%1100.00%
Total29100.00%1100.00%


static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) { return __xchg_cmpxchg(m, val, sizeof *m); }

Contributors

PersonTokensPropCommitsCommitProp
michael s. tsirkinmichael s. tsirkin29100.00%1100.00%
Total29100.00%1100.00%

#endif /* __ASM_SH_CMPXCHG_XCHG_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
michael s. tsirkinmichael s. tsirkin22399.55%150.00%
pan xinhuipan xinhui10.45%150.00%
Total224100.00%2100.00%
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