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