blob: fb3264a968997ca693bbd52eef846175ddb87b3c [file] [log] [blame]
/*
* Copyright 2019 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <cstddef>
#include "instr.h"
#include "utils.h"
constexpr size_t kCacheLineSize = 64;
// Forced memory load. Used during both real and speculative execution to create
// a microarchitectural side effect in the cache. Also used for latency
// measurement in the FLUSH+RELOAD technique.
void ForceRead(const void *p) {
(void)*reinterpret_cast<const volatile char *>(p);
}
// Flush a memory interval from cache. Used to induce speculative execution on
// flushed values until they are fetched back to the cache.
void FlushFromCache(const char *start, const char *end) {
// Start on the first byte and continue in kCacheLineSize steps.
for (const char *ptr = start; ptr < end; ptr += kCacheLineSize) {
CLFlush(ptr);
}
// Flush explicitly the last byte.
CLFlush(end - 1);
}