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Diffstat (limited to 'arch/tile/kernel/futex_64.S')
| -rw-r--r-- | arch/tile/kernel/futex_64.S | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/tile/kernel/futex_64.S b/arch/tile/kernel/futex_64.S new file mode 100644 index 000000000000..f465d1eda20f --- /dev/null +++ b/arch/tile/kernel/futex_64.S @@ -0,0 +1,55 @@ +/* + * 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) |