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 #include <sys/mman.h>
26
StubLayout()27 StubLayout::StubLayout() : table(NULL), count(0) {
28 }
29
initStubTable(unsigned char * table_,size_t count_)30 void StubLayout::initStubTable(unsigned char *table_, size_t count_) {
31 table = table_;
32 count = count_;
33 }
34
allocateStub(void * addr)35 void *StubLayout::allocateStub(void *addr) {
36 // Check if we have created this stub or not.
37 std::map<void *, void *>::iterator index_iter = stub_index.find(addr);
38
39 if (index_iter != stub_index.end()) {
40 return index_iter->second;
41 }
42
43 // We have to create a new stub
44 if (count == 0) {
45 // No free stub slot is available
46 return NULL;
47 }
48
49 // Initialize the stub
50 unsigned char *stub = table;
51 setStubAddress(stub, addr);
52 stub_index.insert(std::make_pair(addr, stub));
53
54 // Increase the free stub slot pointer
55 table += getUnitStubSize();
56 count--;
57
58 return stub;
59 }
60
calcStubTableSize(size_t count) const61 size_t StubLayout::calcStubTableSize(size_t count) const {
62 return count * getUnitStubSize();
63 }
64
getUnitStubSize() const65 size_t StubLayoutARM::getUnitStubSize() const {
66 return 8;
67 }
68
setStubAddress(void * stub_,void * addr)69 void StubLayoutARM::setStubAddress(void *stub_, void *addr) {
70 uint8_t *stub = (uint8_t *)stub_;
71 stub[0] = 0x04; // ldr pc, [pc, #-4]
72 stub[1] = 0xf0; // ldr pc, [pc, #-4]
73 stub[2] = 0x1f; // ldr pc, [pc, #-4]
74 stub[3] = 0xe5; // ldr pc, [pc, #-4]
75
76 void **target = (void **)(stub + 4);
77 *target = addr;
78 }
79
getUnitStubSize() const80 size_t StubLayoutMIPS::getUnitStubSize() const {
81 return 16;
82 }
83
setStubAddress(void * stub_,void * addr)84 void StubLayoutMIPS::setStubAddress(void *stub_, void *addr) {
85 uint32_t addr32 = (uint32_t)(uintptr_t)addr;
86 uint16_t addr_hi16 = (addr32 >> 16) & 0xffff;
87 uint16_t addr_lo16 = addr32 & 0xffff;
88
89 uint32_t *stub = (uint32_t *)stub_;
90 stub[0] = 0x3c190000ul | addr_hi16; // lui
91 stub[1] = 0x37390000ul | addr_lo16; // ori
92 stub[2] = 0x03200008ul; // jr (jump register)
93 stub[3] = 0x00000000ul; // nop
94 }
95