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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/microblaze/include/asm/futex.h
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#ifndef _ASM_MICROBLAZE_FUTEX_H

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

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({									\

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	__asm__ __volatile__ (						\

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			"1:	lwx	%0, %2, r0; "			\

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				insn					\

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			"2:	swx	%1, %2, r0;			\

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				addic	%1, r0, 0;			\

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				bnei	%1, 1b;				\

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			3:						\

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			.section .fixup,\"ax\";				\

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			4:	brid	3b;				\

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				addik	%1, r0, %3;			\

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			.previous;					\

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			.section __ex_table,\"a\";			\

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			.word	1b,4b,2b,4b;				\

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			.previous;"					\

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

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

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	);								\

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})

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static inline int

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futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)

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{

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	int op = (encoded_op >> 28) & 7;

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	int cmp = (encoded_op >> 24) & 15;

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	int oparg = (encoded_op << 8) >> 20;

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	int cmparg = (encoded_op << 20) >> 20;

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	int oldval = 0, ret;

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	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))

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		oparg = 1 << oparg;

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

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		return -EFAULT;

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	pagefault_disable();

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	switch (op) {

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	case FUTEX_OP_SET:

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		__futex_atomic_op("or %1,%4,%4;", 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 %1,%0,%4;", 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 %1,%0,%4;", ret, oldval, uaddr, oparg);

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		break;

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	case FUTEX_OP_ANDN:

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		__futex_atomic_op("andn %1,%0,%4;", 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 %1,%0,%4;", 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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	pagefault_enable();

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	if (!ret) {

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		switch (cmp) {

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		case FUTEX_OP_CMP_EQ:

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			ret = (oldval == cmparg);

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			break;

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		case FUTEX_OP_CMP_NE:

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			ret = (oldval != cmparg);

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			break;

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		case FUTEX_OP_CMP_LT:

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			ret = (oldval < cmparg);

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			break;

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		case FUTEX_OP_CMP_GE:

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			ret = (oldval >= cmparg);

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			break;

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		case FUTEX_OP_CMP_LE:

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			ret = (oldval <= cmparg);

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			break;

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		case FUTEX_OP_CMP_GT:

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			ret = (oldval > cmparg);

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			break;

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		default:

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			ret = -ENOSYS;

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		}

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	}

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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(VERIFY_WRITE, uaddr, sizeof(u32)))

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		return -EFAULT;

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	__asm__ __volatile__ ("1:	lwx	%1, %3, r0;		\

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					cmp	%2, %1, %4;		\

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					beqi	%2, 3f;			\

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				2:	swx	%5, %3, r0;		\

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					addic	%2, r0, 0;		\

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					bnei	%2, 1b;			\

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				3:					\

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				.section .fixup,\"ax\";			\

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				4:	brid	3b;			\

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					addik	%0, r0, %6;		\

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				.previous;				\

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				.section __ex_table,\"a\";		\

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				.word	1b,4b,2b,4b;			\

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				.previous;"				\

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

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

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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

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