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/*
* 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)
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