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/*
* Copyright 2011, The Android Open Source Project
*
* 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
*
* http://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 "StubLayout.h"
#include "utils/flush_cpu_cache.h"
#include "utils/raw_ostream.h"
#include <stdint.h>
#include <stdlib.h>
#include <sys/mman.h>
#if defined(__arm__)
#define STUB_SIZE 8
#elif defined(__mips__)
#define STUB_SIZE 16
#endif
StubLayout::StubLayout() : table(NULL), count(0) {
}
void StubLayout::initStubTable(unsigned char *table_, size_t count_) {
table = table_;
count = count_;
}
void *StubLayout::allocateStub(void *addr) {
#if defined(__arm__) || defined(__mips__)
// Check if we have created this stub or not.
std::map<void *, void *>::iterator index_iter = stub_index.find(addr);
if (index_iter != stub_index.end()) {
return index_iter->second;
}
// We have to create a new stub
if (count == 0) {
// No free stub slot is available
return NULL;
}
// Initialize the stub
unsigned char *stub = table;
setStubAddress(stub, addr);
stub_index.insert(std::make_pair(addr, stub));
// Increase the free stub slot pointer
table += STUB_SIZE;
count--;
return stub;
#else
return NULL;
#endif
}
void StubLayout::setStubAddress(void *stub_, void *addr) {
#if defined(__arm__)
uint8_t *stub = (uint8_t *)stub_;
stub[0] = 0x04; // ldr pc, [pc, #-4]
stub[1] = 0xf0; // ldr pc, [pc, #-4]
stub[2] = 0x1f; // ldr pc, [pc, #-4]
stub[3] = 0xe5; // ldr pc, [pc, #-4]
void **target = (void **)(stub + 4);
*target = addr;
#elif defined(__mips__)
uint32_t addr32 = (uint32_t)(uintptr_t)addr;
uint16_t addr_hi16 = (addr32 >> 16) & 0xffff;
uint16_t addr_lo16 = addr32 & 0xffff;
uint32_t *stub = (uint32_t *)stub_;
stub[0] = 0x3c190000ul | addr_hi16; // lui
stub[1] = 0x37390000ul | addr_lo16; // ori
stub[2] = 0x03200008ul; // jr (jump register)
stub[3] = 0x00000000ul; // nop
#else
rsl_assert(0 && "Stub is not supported on this platform");
#endif
}
size_t StubLayout::calcStubTableSize(size_t count) const {
#if defined(__arm__) || defined(__mips__)
return count * STUB_SIZE;
#else
return 0;
#endif
}
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