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, ...) \ 34STD_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" 46get_user_fault: 47 { movei r1, -EFAULT; jrp lr } 48 ENDPROC(get_user_fault) 49 .popsection 50 51FUTEX_OP(cmpxchg, mtspr CMPEXCH_VALUE, r1; 1: cmpexch4 r0, r0, r2) 52FUTEX_OP(set, 1: exch4 r0, r0, r1) 53FUTEX_OP(add, 1: fetchadd4 r0, r0, r1) 54FUTEX_OP(or, 1: fetchor4 r0, r0, r1) 55FUTEX_OP(andn, nor r1, r1, zero; 1: fetchand4 r0, r0, r1) 56