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//===-- sanitizer_atomic_clang_mips.h ---------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
// Not intended for direct inclusion. Include sanitizer_atomic.h.
//
//===----------------------------------------------------------------------===//
#ifndef SANITIZER_ATOMIC_CLANG_MIPS_H
#define SANITIZER_ATOMIC_CLANG_MIPS_H
namespace __sanitizer {
// MIPS32 does not support atomics > 4 bytes. To address this lack of
// functionality, the sanitizer library provides helper methods which use an
// internal spin lock mechanism to emulate atomic operations when the size is
// 8 bytes.
static void __spin_lock(volatile int *lock) {
while (__sync_lock_test_and_set(lock, 1))
while (*lock) {
}
}
static void __spin_unlock(volatile int *lock) { __sync_lock_release(lock); }
// Make sure the lock is on its own cache line to prevent false sharing.
// Put it inside a struct that is aligned and padded to the typical MIPS
// cacheline which is 32 bytes.
static struct {
int lock;
char pad[32 - sizeof(int)];
} __attribute__((aligned(32))) lock = {0, {0}};
template <>
inline atomic_uint64_t::Type atomic_fetch_add(volatile atomic_uint64_t *ptr,
atomic_uint64_t::Type val,
memory_order mo) {
DCHECK(mo &
(memory_order_relaxed | memory_order_release | memory_order_seq_cst));
DCHECK(!((uptr)ptr % sizeof(*ptr)));
atomic_uint64_t::Type ret;
__spin_lock(&lock.lock);
ret = *(const_cast<atomic_uint64_t::Type volatile *>(&ptr->val_dont_use));
ptr->val_dont_use = ret + val;
__spin_unlock(&lock.lock);
return ret;
}
template <>
inline atomic_uint64_t::Type atomic_fetch_sub(volatile atomic_uint64_t *ptr,
atomic_uint64_t::Type val,
memory_order mo) {
return atomic_fetch_add(ptr, -val, mo);
}
template <>
inline bool atomic_compare_exchange_strong(volatile atomic_uint64_t *ptr,
atomic_uint64_t::Type *cmp,
atomic_uint64_t::Type xchg,
memory_order mo) {
DCHECK(mo &
(memory_order_relaxed | memory_order_release | memory_order_seq_cst));
DCHECK(!((uptr)ptr % sizeof(*ptr)));
typedef atomic_uint64_t::Type Type;
Type cmpv = *cmp;
Type prev;
bool ret = false;
__spin_lock(&lock.lock);
prev = *(const_cast<Type volatile *>(&ptr->val_dont_use));
if (prev == cmpv) {
ret = true;
ptr->val_dont_use = xchg;
}
__spin_unlock(&lock.lock);
return ret;
}
template <>
inline atomic_uint64_t::Type atomic_load(const volatile atomic_uint64_t *ptr,
memory_order mo) {
DCHECK(mo &
(memory_order_relaxed | memory_order_release | memory_order_seq_cst));
DCHECK(!((uptr)ptr % sizeof(*ptr)));
atomic_uint64_t::Type zero = 0;
volatile atomic_uint64_t *Newptr =
const_cast<volatile atomic_uint64_t *>(ptr);
return atomic_fetch_add(Newptr, zero, mo);
}
template <>
inline void atomic_store(volatile atomic_uint64_t *ptr, atomic_uint64_t::Type v,
memory_order mo) {
DCHECK(mo &
(memory_order_relaxed | memory_order_release | memory_order_seq_cst));
DCHECK(!((uptr)ptr % sizeof(*ptr)));
__spin_lock(&lock.lock);
ptr->val_dont_use = v;
__spin_unlock(&lock.lock);
}
} // namespace __sanitizer
#endif // SANITIZER_ATOMIC_CLANG_MIPS_H
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