1 /*
2 * Copyright 2011, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "StubLayout.h"
18
19 #include "utils/flush_cpu_cache.h"
20 #include "utils/raw_ostream.h"
21 #include "utils/rsl_assert.h"
22
23 #include <stdint.h>
24 #include <stdlib.h>
25
StubLayout()26 StubLayout::StubLayout() : table(NULL), count(0) {
27 }
28
initStubTable(unsigned char * table_,size_t count_)29 void StubLayout::initStubTable(unsigned char *table_, size_t count_) {
30 table = table_;
31 count = count_;
32 }
33
allocateStub(void * addr)34 void *StubLayout::allocateStub(void *addr) {
35 // Check if we have created this stub or not.
36 std::map<void *, void *>::iterator index_iter = stub_index.find(addr);
37
38 if (index_iter != stub_index.end()) {
39 return index_iter->second;
40 }
41
42 // We have to create a new stub
43 if (count == 0) {
44 // No free stub slot is available
45 return NULL;
46 }
47
48 // Initialize the stub
49 unsigned char *stub = table;
50 setStubAddress(stub, addr);
51 stub_index.insert(std::make_pair(addr, stub));
52
53 // Increase the free stub slot pointer
54 table += getUnitStubSize();
55 count--;
56
57 return stub;
58 }
59
calcStubTableSize(size_t count) const60 size_t StubLayout::calcStubTableSize(size_t count) const {
61 return count * getUnitStubSize();
62 }
63
getUnitStubSize() const64 size_t StubLayoutARM::getUnitStubSize() const {
65 return 8;
66 }
67
setStubAddress(void * stub_,void * addr)68 void StubLayoutARM::setStubAddress(void *stub_, void *addr) {
69 uint8_t *stub = (uint8_t *)stub_;
70 stub[0] = 0x04; // ldr pc, [pc, #-4]
71 stub[1] = 0xf0; // ldr pc, [pc, #-4]
72 stub[2] = 0x1f; // ldr pc, [pc, #-4]
73 stub[3] = 0xe5; // ldr pc, [pc, #-4]
74
75 void **target = (void **)(stub + 4);
76 *target = addr;
77 }
78
getUnitStubSize() const79 size_t StubLayoutMIPS::getUnitStubSize() const {
80 return 16;
81 }
82
setStubAddress(void * stub_,void * addr)83 void StubLayoutMIPS::setStubAddress(void *stub_, void *addr) {
84 uint32_t addr32 = (uint32_t)(uintptr_t)addr;
85 uint16_t addr_hi16 = (addr32 >> 16) & 0xffff;
86 uint16_t addr_lo16 = addr32 & 0xffff;
87
88 uint32_t *stub = (uint32_t *)stub_;
89 stub[0] = 0x3c190000ul | addr_hi16; // lui
90 stub[1] = 0x37390000ul | addr_lo16; // ori
91 stub[2] = 0x03200008ul; // jr (jump register)
92 stub[3] = 0x00000000ul; // nop
93 }
94