| /* |
| * Copyright 2011 Tilera Corporation. All Rights Reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation, version 2. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
| * NON INFRINGEMENT. See the GNU General Public License for |
| * more details. |
| * |
| * Atomically access user memory, but use MMU to avoid propagating |
| * kernel exceptions. |
| */ |
| |
| #include <linux/linkage.h> |
| #include <asm/errno.h> |
| #include <asm/futex.h> |
| #include <asm/page.h> |
| #include <asm/processor.h> |
| |
| /* |
| * Provide a set of atomic memory operations supporting <asm/futex.h>. |
| * |
| * r0: user address to manipulate |
| * r1: new value to write, or for cmpxchg, old value to compare against |
| * r2: (cmpxchg only) new value to write |
| * |
| * Return __get_user struct, r0 with value, r1 with error. |
| */ |
| #define FUTEX_OP(name, ...) \ |
| STD_ENTRY(futex_##name) \ |
| __VA_ARGS__; \ |
| { \ |
| move r1, zero; \ |
| jrp lr \ |
| }; \ |
| STD_ENDPROC(futex_##name); \ |
| .pushsection __ex_table,"a"; \ |
| .quad 1b, get_user_fault; \ |
| .popsection |
| |
| .pushsection .fixup,"ax" |
| get_user_fault: |
| { movei r1, -EFAULT; jrp lr } |
| ENDPROC(get_user_fault) |
| .popsection |
| |
| FUTEX_OP(cmpxchg, mtspr CMPEXCH_VALUE, r1; 1: cmpexch4 r0, r0, r2) |
| FUTEX_OP(set, 1: exch4 r0, r0, r1) |
| FUTEX_OP(add, 1: fetchadd4 r0, r0, r1) |
| FUTEX_OP(or, 1: fetchor4 r0, r0, r1) |
| FUTEX_OP(andn, nor r1, r1, zero; 1: fetchand4 r0, r0, r1) |
