xref: /freebsd/sys/arm64/linux/linux_support.S (revision 66fd12cf4896eb08ad8e7a2627537f84ead84dd3)
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (C) 2018 Turing Robotic Industries Inc.
5 * Copyright (C) 2022 Dmitry Chagin <dchagin@FreeBSD.org>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include <machine/asm.h>
32__FBSDID("$FreeBSD$");
33
34#include <machine/param.h>
35#include <machine/vmparam.h>
36
37#include <sys/errno.h>
38
39#include "assym.inc"
40
41.macro check_user_access user_arg, limit, bad_addr_func
42	ldr	x7, =(\limit)
43	cmp	x\user_arg, x7
44	b.cs	\bad_addr_func
45.endm
46
47futex_fault:
48	SET_FAULT_HANDLER(xzr, x1)
49	EXIT_USER_ACCESS_CHECK(w0, x1)
50futex_fault_nopcb:
51	mov	x0, #EFAULT
52	ret
53
54#define	LINUX_FUTEX_MAX_LOOPS	128
55
56/*
57 * int oparg, uint32_t *uaddr, int *oldval
58 *
59 * Return 0 on success, errno on failure,
60 * EAGAIN is returned if LL/SC operation fails.
61 *
62 * XXX. VM_MAXUSER_ADDRESS is not applicable here, should be replaced
63 * by something like LINUX_SHAREDPAGE.
64 */
65
66/* (int *)uaddr2 = oparg */
67ENTRY(futex_xchgl)
68	check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
69	adr	x9, futex_fault		/* Load the fault handler */
70	SET_FAULT_HANDLER(x9, x4)	/* And set it */
71	ENTER_USER_ACCESS(w9, x4)
72	mov	w5, #LINUX_FUTEX_MAX_LOOPS
73	prfm	pstl1strm, [x1]
74	mov	w6, w0			/* Save oparg */
751:	ldxr	w4, [x1]		/* Load oldval from uaddr */
76	stlxr	w0, w6, [x1]		/* Store oparg to uaddr */
77	cbz	w0, 3f			/* Exit on success */
78	sub	w5, w5, w0		/* Dec loop counter, w0 is 1 */
79	cbnz	w5, 1b			/* Loop */
80	mov	x0, #EAGAIN		/* Store of newval failed */
813:	dmb	ish
82	EXIT_USER_ACCESS(w9)
83	SET_FAULT_HANDLER(xzr, x9)	/* Reset the fault handler */
84	str w4, [x2]			/* Store oldval */
85	ret
86END(futex_xchgl)
87
88/* (int *)uaddr2 += oparg */
89ENTRY(futex_addl)
90	check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
91	adr	x9, futex_fault
92	SET_FAULT_HANDLER(x9, x4)
93	ENTER_USER_ACCESS(w9, x4)
94	mov	w5, #LINUX_FUTEX_MAX_LOOPS
95	prfm	pstl1strm, [x1]
96	mov	w6, w0
971:	ldxr	w4, [x1]
98	add	w3, w4, w6		/* oldval + oparg */
99	stlxr	w0, w3, [x1]
100	cbz	w0, 3f
101	sub	w5, w5, w0
102	cbnz	w5, 1b
103	mov	x0, #EAGAIN
1043:	dmb	ish
105	EXIT_USER_ACCESS(w9)
106	SET_FAULT_HANDLER(xzr, x9)
107	str w4, [x2]
108	ret
109END(futex_addl)
110
111/* (int *)uaddr2 |= oparg */
112ENTRY(futex_orl)
113	check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
114	adr	x9, futex_fault
115	SET_FAULT_HANDLER(x9, x4)
116	ENTER_USER_ACCESS(w9, x4)
117	mov	w5, #LINUX_FUTEX_MAX_LOOPS
118	prfm	pstl1strm, [x1]
119	mov	w6, w0
1201:	ldxr	w4, [x1]
121	orr	w3, w4, w6		/* oldavl |= oparg */
122	stlxr	w0, w3, [x1]
123	cbz	w0, 3f
124	sub	w5, w5, w0
125	cbnz	w5, 1b
126	mov	x0, #EAGAIN
1273:	dmb	ish
128	EXIT_USER_ACCESS(w9)
129	SET_FAULT_HANDLER(xzr, x9)
130	str w4, [x2]
131	ret
132END(futex_orl)
133
134/* (int *)uaddr2 &= oparg */
135ENTRY(futex_andl)
136	check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
137	adr	x9, futex_fault
138	SET_FAULT_HANDLER(x9, x4)
139	ENTER_USER_ACCESS(w9, x4)
140	mov	w5, #LINUX_FUTEX_MAX_LOOPS
141	prfm	pstl1strm, [x1]
142	mov	w6, w0
1431:	ldxr	w4, [x1]
144	and	w3, w4, w6		/* oldval &= oparg */
145	stlxr	w0, w3, [x1]
146	cbz	w0, 3f
147	sub	w5, w5, w0
148	cbnz	w5, 1b
149	mov	x0, #EAGAIN
1503:	dmb	ish
151	EXIT_USER_ACCESS(w9)
152	SET_FAULT_HANDLER(xzr, x9)
153	str w4, [x2]
154	ret
155END(futex_andl)
156
157/* (int *)uaddr2 ^= oparg */
158ENTRY(futex_xorl)
159	check_user_access 1, (VM_MAXUSER_ADDRESS-3), futex_fault_nopcb
160	adr	x9, futex_fault
161	SET_FAULT_HANDLER(x9, x4)
162	ENTER_USER_ACCESS(w9, x4)
163	mov	w5, #LINUX_FUTEX_MAX_LOOPS
164	prfm	pstl1strm, [x1]
165	mov	w6, w0
1661:	ldxr	w4, [x1]
167	eor	w3, w4, w6		/* oldval ^= oparg */
168	stlxr	w0, w3, [x1]
169	cbz	w0, 3f
170	sub	w5, w5, w0
171	cbnz	w5, 1b
172	mov	x0, #EAGAIN
1733:	dmb	ish
174	EXIT_USER_ACCESS(w9)
175	SET_FAULT_HANDLER(xzr, x9)
176	str w4, [x2]
177	ret
178END(futex_xorl)
179