futex.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Atomic futex routines
  4 *
  5 * Based on the PowerPC implementataion
  6 *
  7 * Copyright (C) 2013 TangoTec Ltd.
  8 *
  9 * Baruch Siach <baruch@tkos.co.il>
 10 */
 11
 12#ifndef _ASM_XTENSA_FUTEX_H
 13#define _ASM_XTENSA_FUTEX_H
 14
 15#include <linux/futex.h>
 16#include <linux/uaccess.h>
 17#include <linux/errno.h>
 18
 19#define arch_futex_atomic_op_inuser arch_futex_atomic_op_inuser
 20#define futex_atomic_cmpxchg_inatomic futex_atomic_cmpxchg_inatomic
 21#include <asm-generic/futex.h>
 22
 23#if XCHAL_HAVE_EXCLUSIVE
 24#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
 25	__asm__ __volatile(				\
 26	"1:	l32ex	%[oldval], %[addr]\n"		\
 27		insn "\n"				\
 28	"2:	s32ex	%[newval], %[addr]\n"		\
 29	"	getex	%[newval]\n"			\
 30	"	beqz	%[newval], 1b\n"		\
 31	"	movi	%[newval], 0\n"			\
 32	"3:\n"						\
 33	"	.section .fixup,\"ax\"\n"		\
 34	"	.align 4\n"				\
 35	"	.literal_position\n"			\
 36	"5:	movi	%[oldval], 3b\n"		\
 37	"	movi	%[newval], %[fault]\n"		\
 38	"	jx	%[oldval]\n"			\
 39	"	.previous\n"				\
 40	"	.section __ex_table,\"a\"\n"		\
 41	"	.long 1b, 5b, 2b, 5b\n"			\
 42	"	.previous\n"				\
 43	: [oldval] "=&r" (old), [newval] "=&r" (ret)	\
 44	: [addr] "r" (uaddr), [oparg] "r" (arg),	\
 45	  [fault] "I" (-EFAULT)				\
 46	: "memory")
 47#elif XCHAL_HAVE_S32C1I
 48#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
 49	__asm__ __volatile(				\
 50	"1:	l32i	%[oldval], %[mem]\n"		\
 51		insn "\n"				\
 52	"	wsr	%[oldval], scompare1\n"		\
 53	"2:	s32c1i	%[newval], %[mem]\n"		\
 54	"	bne	%[newval], %[oldval], 1b\n"	\
 55	"	movi	%[newval], 0\n"			\
 56	"3:\n"						\
 57	"	.section .fixup,\"ax\"\n"		\
 58	"	.align 4\n"				\
 59	"	.literal_position\n"			\
 60	"5:	movi	%[oldval], 3b\n"		\
 61	"	movi	%[newval], %[fault]\n"		\
 62	"	jx	%[oldval]\n"			\
 63	"	.previous\n"				\
 64	"	.section __ex_table,\"a\"\n"		\
 65	"	.long 1b, 5b, 2b, 5b\n"			\
 66	"	.previous\n"				\
 67	: [oldval] "=&r" (old), [newval] "=&r" (ret),	\
 68	  [mem] "+m" (*(uaddr))				\
 69	: [oparg] "r" (arg), [fault] "I" (-EFAULT)	\
 70	: "memory")
 71#endif
 72
 73static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
 74		u32 __user *uaddr)
 75{
 76#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
 77	int oldval = 0, ret;
 78
 79	if (!access_ok(uaddr, sizeof(u32)))
 80		return -EFAULT;
 81
 82	switch (op) {
 83	case FUTEX_OP_SET:
 84		__futex_atomic_op("mov %[newval], %[oparg]",
 85				  ret, oldval, uaddr, oparg);
 86		break;
 87	case FUTEX_OP_ADD:
 88		__futex_atomic_op("add %[newval], %[oldval], %[oparg]",
 89				  ret, oldval, uaddr, oparg);
 90		break;
 91	case FUTEX_OP_OR:
 92		__futex_atomic_op("or %[newval], %[oldval], %[oparg]",
 93				  ret, oldval, uaddr, oparg);
 94		break;
 95	case FUTEX_OP_ANDN:
 96		__futex_atomic_op("and %[newval], %[oldval], %[oparg]",
 97				  ret, oldval, uaddr, ~oparg);
 98		break;
 99	case FUTEX_OP_XOR:
100		__futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
101				  ret, oldval, uaddr, oparg);
102		break;
103	default:
104		ret = -ENOSYS;
105	}
106
107	if (!ret)
108		*oval = oldval;
109
110	return ret;
111#else
112	return futex_atomic_op_inuser_local(op, oparg, oval, uaddr);
113#endif
114}
115
116static inline int
117futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
118			      u32 oldval, u32 newval)
119{
120#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
121	unsigned long tmp;
122	int ret = 0;
123
124	if (!access_ok(uaddr, sizeof(u32)))
125		return -EFAULT;
126
127	__asm__ __volatile__ (
128	"	# futex_atomic_cmpxchg_inatomic\n"
129#if XCHAL_HAVE_EXCLUSIVE
130	"1:	l32ex	%[tmp], %[addr]\n"
131	"	s32i	%[tmp], %[uval], 0\n"
132	"	bne	%[tmp], %[oldval], 2f\n"
133	"	mov	%[tmp], %[newval]\n"
134	"3:	s32ex	%[tmp], %[addr]\n"
135	"	getex	%[tmp]\n"
136	"	beqz	%[tmp], 1b\n"
137#elif XCHAL_HAVE_S32C1I
138	"	wsr	%[oldval], scompare1\n"
139	"1:	s32c1i	%[newval], %[addr], 0\n"
140	"	s32i	%[newval], %[uval], 0\n"
141#endif
142	"2:\n"
143	"	.section .fixup,\"ax\"\n"
144	"	.align 4\n"
145	"	.literal_position\n"
146	"4:	movi	%[tmp], 2b\n"
147	"	movi	%[ret], %[fault]\n"
148	"	jx	%[tmp]\n"
149	"	.previous\n"
150	"	.section __ex_table,\"a\"\n"
151	"	.long 1b, 4b\n"
152#if XCHAL_HAVE_EXCLUSIVE
153	"	.long 3b, 4b\n"
154#endif
155	"	.previous\n"
156	: [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
157	: [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
158	  [fault] "I" (-EFAULT)
159	: "memory");
160
161	return ret;
162#else
163	return futex_atomic_cmpxchg_inatomic_local(uval, uaddr, oldval, newval);
164#endif
165}
166
167#endif /* _ASM_XTENSA_FUTEX_H */