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kernel
os
linux
Hexagon: Add atomic ops support
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
authored by
Richard Kuo
and committed by
Linus Torvalds
75085018
a86a7ce3
+164
+164
arch/hexagon/include/asm/atomic.h
+164
arch/hexagon/include/asm/atomic.h
···
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/*
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* Atomic operations for the Hexagon architecture
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*
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* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#ifndef _ASM_ATOMIC_H
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#define _ASM_ATOMIC_H
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#include <linux/types.h>
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#define ATOMIC_INIT(i) { (i) }
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#define atomic_set(v, i) ((v)->counter = (i))
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/**
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* atomic_read - reads a word, atomically
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* @v: pointer to atomic value
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*
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* Assumes all word reads on our architecture are atomic.
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*/
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#define atomic_read(v) ((v)->counter)
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/**
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* atomic_xchg - atomic
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* @v: pointer to memory to change
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* @new: new value (technically passed in a register -- see xchg)
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*/
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#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
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/**
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* atomic_cmpxchg - atomic compare-and-exchange values
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* @v: pointer to value to change
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* @old: desired old value to match
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* @new: new value to put in
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*
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* Parameters are then pointer, value-in-register, value-in-register,
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* and the output is the old value.
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*
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* Apparently this is complicated for archs that don't support
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* the memw_locked like we do (or it's broken or whatever).
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*
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* Kind of the lynchpin of the rest of the generically defined routines.
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* Remember V2 had that bug with dotnew predicate set by memw_locked.
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*
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* "old" is "expected" old val, __oldval is actual old value
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*/
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int __oldval;
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asm volatile(
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"1: %0 = memw_locked(%1);\n"
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" { P0 = cmp.eq(%0,%2);\n"
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" if (!P0.new) jump:nt 2f; }\n"
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" memw_locked(%1,P0) = %3;\n"
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" if (!P0) jump 1b;\n"
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"2:\n"
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: "=&r" (__oldval)
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: "r" (&v->counter), "r" (old), "r" (new)
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: "memory", "p0"
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);
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return __oldval;
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}
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static inline int atomic_add_return(int i, atomic_t *v)
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{
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int output;
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__asm__ __volatile__ (
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"1: %0 = memw_locked(%1);\n"
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" %0 = add(%0,%2);\n"
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" memw_locked(%1,P3)=%0;\n"
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" if !P3 jump 1b;\n"
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: "=&r" (output)
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: "r" (&v->counter), "r" (i)
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: "memory", "p3"
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);
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return output;
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}
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#define atomic_add(i, v) atomic_add_return(i, (v))
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static inline int atomic_sub_return(int i, atomic_t *v)
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{
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int output;
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__asm__ __volatile__ (
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"1: %0 = memw_locked(%1);\n"
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" %0 = sub(%0,%2);\n"
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" memw_locked(%1,P3)=%0\n"
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" if !P3 jump 1b;\n"
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: "=&r" (output)
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: "r" (&v->counter), "r" (i)
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: "memory", "p3"
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);
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return output;
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}
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#define atomic_sub(i, v) atomic_sub_return(i, (v))
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/**
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* atomic_add_unless - add unless the number is a given value
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* @v: pointer to value
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* @a: amount to add
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* @u: unless value is equal to u
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*
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* Returns 1 if the add happened, 0 if it didn't.
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*/
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static inline int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int output, __oldval;
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asm volatile(
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"1: %0 = memw_locked(%2);"
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" {"
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" p3 = cmp.eq(%0, %4);"
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" if (p3.new) jump:nt 2f;"
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" %0 = add(%0, %3);"
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" %1 = #0;"
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" }"
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" memw_locked(%2, p3) = %0;"
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" {"
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" if !p3 jump 1b;"
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" %1 = #1;"
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" }"
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"2:"
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: "=&r" (__oldval), "=&r" (output)
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: "r" (v), "r" (a), "r" (u)
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: "memory", "p3"
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);
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return output;
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}
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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#define atomic_inc(v) atomic_add(1, (v))
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#define atomic_dec(v) atomic_sub(1, (v))
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#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
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#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
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#define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0)
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#define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
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#define atomic_inc_return(v) (atomic_add_return(1, v))
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#define atomic_dec_return(v) (atomic_sub_return(1, v))
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#endif