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 "MemChunk.h"
18
19#include "utils/flush_cpu_cache.h"
20#include "utils/helper.h"
21
22#include <llvm/Support/raw_ostream.h>
23
24#include <sys/mman.h>
25
26#include <stdlib.h>
27
28#ifndef MAP_32BIT
29#define MAP_32BIT 0
30// Note: If the <sys/mman.h> does not come with MAP_32BIT, then we
31// define it as zero, so that it won't manipulate the flags.
32#endif
33
34//#define USE_FIXED_ADDR_MEM_CHUNK 1
35
36#if USE_FIXED_ADDR_MEM_CHUNK
37static uintptr_t StartAddr = 0x7e000000UL;
38#endif
39
40MemChunk::MemChunk() : buf((unsigned char *)MAP_FAILED), buf_size(0) {
41}
42
43MemChunk::~MemChunk() {
44  if (buf != MAP_FAILED) {
45    munmap(buf, buf_size);
46  }
47}
48
49bool MemChunk::allocate(size_t size) {
50#if USE_FIXED_ADDR_MEM_CHUNK
51  buf = (unsigned char *)mmap((void *)StartAddr, size,
52                              PROT_READ | PROT_WRITE,
53                              MAP_PRIVATE | MAP_ANON | MAP_32BIT,
54                              -1, 0);
55#else
56  buf = (unsigned char *)mmap(0, size,
57                              PROT_READ | PROT_WRITE,
58                              MAP_PRIVATE | MAP_ANON | MAP_32BIT,
59                              -1, 0);
60#endif
61
62  if (buf == MAP_FAILED) {
63    return false;
64  }
65
66#if USE_FIXED_ADDR_MEM_CHUNK
67  StartAddr += (size + 4095) / 4096 * 4096;
68#endif
69
70  buf_size = size;
71  return true;
72}
73
74void MemChunk::print() const {
75  if (buf != MAP_FAILED) {
76    dump_hex(buf, buf_size, 0, buf_size);
77  }
78}
79
80bool MemChunk::protect(int prot) {
81  if (buf_size > 0) {
82    int ret = mprotect((void *)buf, buf_size, prot);
83    if (ret == -1) {
84      llvm::errs() << "Error: Can't mprotect.\n";
85      return false;
86    }
87
88    if (prot & PROT_EXEC) {
89      FLUSH_CPU_CACHE(buf, buf + buf_size);
90    }
91  }
92
93  return true;
94}
95