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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/alpha/include/asm/futex.h
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/* SPDX-License-Identifier: GPL-2.0 */

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#ifndef _ASM_ALPHA_FUTEX_H

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#define _ASM_ALPHA_FUTEX_H

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#ifdef __KERNEL__

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#include <linux/futex.h>

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#include <linux/uaccess.h>

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#include <asm/errno.h>

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#include <asm/barrier.h>

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#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\

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	__asm__ __volatile__(					\

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		__ASM_SMP_MB					\

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	"1:	ldl_l	%0,0(%2)\n"				\

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		insn						\

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	"2:	stl_c	%1,0(%2)\n"				\

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	"	beq	%1,4f\n"				\

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	"	mov	$31,%1\n"				\

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	"3:	.subsection 2\n"				\

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	"4:	br	1b\n"					\

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	"	.previous\n"					\

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	EXC(1b,3b,$31,%1)					\

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	EXC(2b,3b,$31,%1)					\

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	:	"=&r" (oldval), "=&r"(ret)			\

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	:	"r" (uaddr), "r"(oparg)				\

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	:	"memory")

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static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,

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		u32 __user *uaddr)

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{

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	int oldval = 0, ret;

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	if (!access_ok(uaddr, sizeof(u32)))

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		return -EFAULT;

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	switch (op) {

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	case FUTEX_OP_SET:

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		__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_ADD:

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		__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_OR:

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		__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_ANDN:

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		__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_XOR:

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		__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);

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		break;

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	default:

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		ret = -ENOSYS;

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	}

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	if (!ret)

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		*oval = oldval;

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	return ret;

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}

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static inline int

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futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,

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			      u32 oldval, u32 newval)

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{

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	int ret = 0, cmp;

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	u32 prev;

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	if (!access_ok(uaddr, sizeof(u32)))

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		return -EFAULT;

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	__asm__ __volatile__ (

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		__ASM_SMP_MB

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	"1:	ldl_l	%1,0(%3)\n"

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	"	cmpeq	%1,%4,%2\n"

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	"	beq	%2,3f\n"

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	"	mov	%5,%2\n"

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	"2:	stl_c	%2,0(%3)\n"

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	"	beq	%2,4f\n"

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	"3:	.subsection 2\n"

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	"4:	br	1b\n"

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	"	.previous\n"

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	EXC(1b,3b,$31,%0)

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	EXC(2b,3b,$31,%0)

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	:	"+r"(ret), "=&r"(prev), "=&r"(cmp)

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	:	"r"(uaddr), "r"((long)(int)oldval), "r"(newval)

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	:	"memory");

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	*uval = prev;

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	return ret;

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}

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#endif /* __KERNEL__ */

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#endif /* _ASM_ALPHA_FUTEX_H */

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