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

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#ifndef __ASM_CSKY_FUTEX_H

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#define __ASM_CSKY_FUTEX_H

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#ifndef CONFIG_SMP

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#include <asm-generic/futex.h>

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#else

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#include <linux/atomic.h>

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#include <linux/futex.h>

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#include <linux/uaccess.h>

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#include <linux/errno.h>

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

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{									\

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	u32 tmp;							\

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									\

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	__atomic_pre_full_fence();					\

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									\

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	__asm__ __volatile__ (						\

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	"1:	ldex.w	%[ov], %[u]			\n"		\

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	"	"insn"					\n"		\

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	"2:	stex.w	%[t], %[u]			\n"		\

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	"	bez	%[t], 1b			\n"		\

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	"	br	4f				\n"		\

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	"3:	mov	%[r], %[e]			\n"		\

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	"4:						\n"		\

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

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	"	.balign 4				\n"		\

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	"	.long	1b, 3b				\n"		\

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	"	.long	2b, 3b				\n"		\

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	"	.previous				\n"		\

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	: [r] "+r" (ret), [ov] "=&r" (oldval),				\

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	  [u] "+m" (*uaddr), [t] "=&r" (tmp)				\

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	: [op] "Jr" (oparg), [e] "jr" (-EFAULT)				\

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	: "memory");							\

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									\

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	__atomic_post_full_fence();					\

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}

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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 = 0;

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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 %[t], %[ov]",

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				  ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_ADD:

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		__futex_atomic_op("add %[t], %[ov], %[op]",

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				  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 %[t], %[ov], %[op]",

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				  ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_ANDN:

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		__futex_atomic_op("and %[t], %[ov], %[op]",

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				  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 %[t], %[ov], %[op]",

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				  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;

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	u32 val, tmp;

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

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		return -EFAULT;

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	__atomic_pre_full_fence();

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	__asm__ __volatile__ (

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	"1:	ldex.w	%[v], %[u]			\n"

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	"	cmpne	%[v], %[ov]			\n"

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	"	bt	4f				\n"

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	"	mov	%[t], %[nv]			\n"

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	"2:	stex.w	%[t], %[u]			\n"

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	"	bez	%[t], 1b			\n"

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	"	br	4f				\n"

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	"3:	mov	%[r], %[e]			\n"

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	"4:						\n"

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

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	"	.balign 4				\n"

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	"	.long	1b, 3b				\n"

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	"	.long	2b, 3b				\n"

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	"	.previous				\n"

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	: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr),

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	  [t] "=&r" (tmp)

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	: [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "Jr" (-EFAULT)

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	: "memory");

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	__atomic_post_full_fence();

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	*uval = val;

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	return ret;

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}

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#endif /* CONFIG_SMP */

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#endif /* __ASM_CSKY_FUTEX_H */

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