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

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#ifndef _ASM_HEXAGON_FUTEX_H

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#define _ASM_HEXAGON_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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/* XXX TODO-- need to add sync barriers! */

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

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	__asm__ __volatile( \

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	"1: %0 = memw_locked(%3);\n" \

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	    /* For example: %1 = %4 */ \

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	    insn \

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	"2: memw_locked(%3,p2) = %1;\n" \

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	"   if (!p2) jump 1b;\n" \

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	"   %1 = #0;\n" \

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	"3:\n" \

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	".section .fixup,\"ax\"\n" \

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	"4: %1 = #%5;\n" \

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	"   jump ##3b\n" \

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	".previous\n" \

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	".section __ex_table,\"a\"\n" \

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	".long 1b,4b,2b,4b\n" \

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	".previous\n" \

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	: "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \

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	: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \

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	: "p2", "memory")

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static inline int

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arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 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("%1 = %4\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("%1 = add(%0,%4)\n", ret, oldval, uaddr,

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				  oparg);

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		break;

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	case FUTEX_OP_OR:

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		__futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,

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				  oparg);

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		break;

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	case FUTEX_OP_ANDN:

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		__futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,

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				  oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_XOR:

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		__futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,

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				  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, u32 oldval,

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			      u32 newval)

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{

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	int prev;

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	int ret;

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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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	"1: %1 = memw_locked(%3)\n"

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	"   {\n"

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	"      p2 = cmp.eq(%1,%4)\n"

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	"      if (!p2.new) jump:NT 3f\n"

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	"   }\n"

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	"2: memw_locked(%3,p2) = %5\n"

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	"   if (!p2) jump 1b\n"

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	"3:\n"

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	".section .fixup,\"ax\"\n"

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	"4: %0 = #%6\n"

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	"   jump ##3b\n"

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	".previous\n"

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	".section __ex_table,\"a\"\n"

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	".long 1b,4b,2b,4b\n"

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	".previous\n"

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	: "+r" (ret), "=&r" (prev), "+m" (*uaddr)

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	: "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)

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	: "p2", "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_HEXAGON_FUTEX_H */

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