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#if USE_FIXED_ADDR_MEM_CHUNK
35static uintptr_t StartAddr = 0x7e000000UL;
36#endif
37
38MemChunk::MemChunk() : buf((unsigned char *)MAP_FAILED), buf_size(0) {
39}
40
41MemChunk::~MemChunk() {
42  if (buf != MAP_FAILED) {
43    munmap(buf, buf_size);
44  }
45}
46
47bool MemChunk::allocate(size_t size) {
48#if USE_FIXED_ADDR_MEM_CHUNK
49  buf = (unsigned char *)mmap((void *)StartAddr, size,
50                              PROT_READ | PROT_WRITE,
51                              MAP_PRIVATE | MAP_ANON | MAP_32BIT,
52                              -1, 0);
53#else
54  buf = (unsigned char *)mmap(0, size,
55                              PROT_READ | PROT_WRITE,
56                              MAP_PRIVATE | MAP_ANON | MAP_32BIT,
57                              -1, 0);
58#endif
59
60  if (buf == MAP_FAILED) {
61    return false;
62  }
63
64#if USE_FIXED_ADDR_MEM_CHUNK
65  StartAddr += (size + 4095) / 4096 * 4096;
66#endif
67
68  buf_size = size;
69  return true;
70}
71
72void MemChunk::print() const {
73  if (buf != MAP_FAILED) {
74    dump_hex(buf, buf_size, 0, buf_size);
75  }
76}
77
78bool MemChunk::protect(int prot) {
79  if (buf_size > 0) {
80    int ret = mprotect((void *)buf, buf_size, prot);
81    if (ret == -1) {
82      llvm::errs() << "Error: Can't mprotect.\n";
83      return false;
84    }
85
86    if (prot & PROT_EXEC) {
87      FLUSH_CPU_CACHE(buf, buf + buf_size);
88    }
89  }
90
91  return true;
92}
93