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18aecc2b CM |
1 | /* |
2 | * Copyright 2011 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * Atomically access user memory, but use MMU to avoid propagating | |
15 | * kernel exceptions. | |
16 | */ | |
17 | ||
18 | #include <linux/linkage.h> | |
19 | #include <asm/errno.h> | |
20 | #include <asm/futex.h> | |
21 | #include <asm/page.h> | |
22 | #include <asm/processor.h> | |
23 | ||
24 | /* | |
25 | * Provide a set of atomic memory operations supporting <asm/futex.h>. | |
26 | * | |
27 | * r0: user address to manipulate | |
28 | * r1: new value to write, or for cmpxchg, old value to compare against | |
29 | * r2: (cmpxchg only) new value to write | |
30 | * | |
31 | * Return __get_user struct, r0 with value, r1 with error. | |
32 | */ | |
33 | #define FUTEX_OP(name, ...) \ | |
34 | STD_ENTRY(futex_##name) \ | |
35 | __VA_ARGS__; \ | |
36 | { \ | |
37 | move r1, zero; \ | |
38 | jrp lr \ | |
39 | }; \ | |
40 | STD_ENDPROC(futex_##name); \ | |
41 | .pushsection __ex_table,"a"; \ | |
42 | .quad 1b, get_user_fault; \ | |
43 | .popsection | |
44 | ||
45 | .pushsection .fixup,"ax" | |
46 | get_user_fault: | |
47 | { movei r1, -EFAULT; jrp lr } | |
48 | ENDPROC(get_user_fault) | |
49 | .popsection | |
50 | ||
51 | FUTEX_OP(cmpxchg, mtspr CMPEXCH_VALUE, r1; 1: cmpexch4 r0, r0, r2) | |
52 | FUTEX_OP(set, 1: exch4 r0, r0, r1) | |
53 | FUTEX_OP(add, 1: fetchadd4 r0, r0, r1) | |
54 | FUTEX_OP(or, 1: fetchor4 r0, r0, r1) | |
55 | FUTEX_OP(andn, nor r1, r1, zero; 1: fetchand4 r0, r0, r1) |