1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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
47 futex_fault:
48 SET_FAULT_HANDLER(xzr, x1)
49 EXIT_USER_ACCESS_CHECK(w0, x1)
50 futex_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 */
67 ENTRY(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 */
75 1: 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 */
81 3: 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
86 END(futex_xchgl)
87
88 /* (int *)uaddr2 += oparg */
89 ENTRY(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
97 1: 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
104 3: dmb ish
105 EXIT_USER_ACCESS(w9)
106 SET_FAULT_HANDLER(xzr, x9)
107 str w4, [x2]
108 ret
109 END(futex_addl)
110
111 /* (int *)uaddr2 |= oparg */
112 ENTRY(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
120 1: 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
127 3: dmb ish
128 EXIT_USER_ACCESS(w9)
129 SET_FAULT_HANDLER(xzr, x9)
130 str w4, [x2]
131 ret
132 END(futex_orl)
133
134 /* (int *)uaddr2 &= oparg */
135 ENTRY(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
143 1: 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
150 3: dmb ish
151 EXIT_USER_ACCESS(w9)
152 SET_FAULT_HANDLER(xzr, x9)
153 str w4, [x2]
154 ret
155 END(futex_andl)
156
157 /* (int *)uaddr2 ^= oparg */
158 ENTRY(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
166 1: 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
173 3: dmb ish
174 EXIT_USER_ACCESS(w9)
175 SET_FAULT_HANDLER(xzr, x9)
176 str w4, [x2]
177 ret
178 END(futex_xorl)
Cache object: d8896947648e9ff8483fd463fec79567
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