| Chris Metcalf | 18aecc2 | 2011-05-04 14:38:26 -0400 | [diff] [blame] | 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) |