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/*
* Derived from Linux arch64 spinlock.h which is:
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_ARM64_SPINLOCK_H
#define __ASM_ARM64_SPINLOCK_H
typedef struct {
volatile unsigned int lock;
} raw_spinlock_t;
#define _RAW_SPIN_LOCK_UNLOCKED { 0 }
#define _raw_spin_is_locked(x) ((x)->lock != 0)
static always_inline void _raw_spin_unlock(raw_spinlock_t *lock)
{
ASSERT(_raw_spin_is_locked(lock));
asm volatile(
" stlr %w1, [%0]\n"
: : "r" (&lock->lock), "r" (0) : "memory");
}
static always_inline int _raw_spin_trylock(raw_spinlock_t *lock)
{
unsigned int tmp;
asm volatile(
" ldaxr %w0, [%1]\n"
" cbnz %w0, 1f\n"
" stxr %w0, %w2, [%1]\n"
"1:\n"
: "=&r" (tmp)
: "r" (&lock->lock), "r" (1)
: "memory");
return !tmp;
}
typedef struct {
volatile unsigned int lock;
} raw_rwlock_t;
#define _RAW_RW_LOCK_UNLOCKED { 0 }
static always_inline int _raw_read_trylock(raw_rwlock_t *rw)
{
unsigned int tmp, tmp2 = 1;
asm volatile(
" ldaxr %w0, [%2]\n"
" add %w0, %w0, #1\n"
" tbnz %w0, #31, 1f\n"
" stxr %w1, %w0, [%2]\n"
"1:\n"
: "=&r" (tmp), "+r" (tmp2)
: "r" (&rw->lock)
: "memory");
return !tmp2;
}
static always_inline int _raw_write_trylock(raw_rwlock_t *rw)
{
unsigned int tmp;
asm volatile(
" ldaxr %w0, [%1]\n"
" cbnz %w0, 1f\n"
" stxr %w0, %w2, [%1]\n"
"1:\n"
: "=&r" (tmp)
: "r" (&rw->lock), "r" (0x80000000)
: "memory");
return !tmp;
}
static inline void _raw_read_unlock(raw_rwlock_t *rw)
{
unsigned int tmp, tmp2;
asm volatile(
"1: ldxr %w0, [%2]\n"
" sub %w0, %w0, #1\n"
" stlxr %w1, %w0, [%2]\n"
" cbnz %w1, 1b\n"
: "=&r" (tmp), "=&r" (tmp2)
: "r" (&rw->lock)
: "memory");
}
static inline void _raw_write_unlock(raw_rwlock_t *rw)
{
asm volatile(
" stlr %w1, [%0]\n"
: : "r" (&rw->lock), "r" (0) : "memory");
}
#define _raw_rw_is_locked(x) ((x)->lock != 0)
#define _raw_rw_is_write_locked(x) ((x)->lock == 0x80000000)
#endif /* __ASM_SPINLOCK_H */
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* indent-tabs-mode: nil
* End:
*/
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