Line data Source code
1 : // Copyright 2012 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : // Platform-specific code for Linux goes here. For the POSIX-compatible
6 : // parts, the implementation is in platform-posix.cc.
7 :
8 : #include <pthread.h>
9 : #include <semaphore.h>
10 : #include <signal.h>
11 : #include <stdio.h>
12 : #include <stdlib.h>
13 : #include <sys/prctl.h>
14 : #include <sys/resource.h>
15 : #include <sys/syscall.h>
16 : #include <sys/time.h>
17 :
18 : // Ubuntu Dapper requires memory pages to be marked as
19 : // executable. Otherwise, OS raises an exception when executing code
20 : // in that page.
21 : #include <errno.h>
22 : #include <fcntl.h> // open
23 : #include <stdarg.h>
24 : #include <strings.h> // index
25 : #include <sys/mman.h> // mmap & munmap
26 : #include <sys/stat.h> // open
27 : #include <sys/types.h> // mmap & munmap
28 : #include <unistd.h> // sysconf
29 :
30 : // GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
31 : // Old versions of the C library <signal.h> didn't define the type.
32 : #if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
33 : (defined(__arm__) || defined(__aarch64__)) && \
34 : !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
35 : #include <asm/sigcontext.h> // NOLINT
36 : #endif
37 :
38 : #include <cmath>
39 :
40 : #undef MAP_TYPE
41 :
42 : #include "src/base/macros.h"
43 : #include "src/base/platform/platform-posix-time.h"
44 : #include "src/base/platform/platform-posix.h"
45 : #include "src/base/platform/platform.h"
46 :
47 : namespace v8 {
48 : namespace base {
49 :
50 : #ifdef __arm__
51 :
52 : bool OS::ArmUsingHardFloat() {
53 : // GCC versions 4.6 and above define __ARM_PCS or __ARM_PCS_VFP to specify
54 : // the Floating Point ABI used (PCS stands for Procedure Call Standard).
55 : // We use these as well as a couple of other defines to statically determine
56 : // what FP ABI used.
57 : // GCC versions 4.4 and below don't support hard-fp.
58 : // GCC versions 4.5 may support hard-fp without defining __ARM_PCS or
59 : // __ARM_PCS_VFP.
60 :
61 : #define GCC_VERSION \
62 : (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
63 : #if GCC_VERSION >= 40600 && !defined(__clang__)
64 : #if defined(__ARM_PCS_VFP)
65 : return true;
66 : #else
67 : return false;
68 : #endif
69 :
70 : #elif GCC_VERSION < 40500 && !defined(__clang__)
71 : return false;
72 :
73 : #else
74 : #if defined(__ARM_PCS_VFP)
75 : return true;
76 : #elif defined(__ARM_PCS) || defined(__SOFTFP__) || defined(__SOFTFP) || \
77 : !defined(__VFP_FP__)
78 : return false;
79 : #else
80 : #error \
81 : "Your version of compiler does not report the FP ABI compiled for." \
82 : "Please report it on this issue" \
83 : "http://code.google.com/p/v8/issues/detail?id=2140"
84 :
85 : #endif
86 : #endif
87 : #undef GCC_VERSION
88 : }
89 :
90 : #endif // def __arm__
91 :
92 54993 : TimezoneCache* OS::CreateTimezoneCache() {
93 109986 : return new PosixDefaultTimezoneCache();
94 : }
95 :
96 : // Constants used for mmap.
97 : static const int kMmapFd = -1;
98 : static const int kMmapFdOffset = 0;
99 :
100 207 : void* OS::Allocate(const size_t requested, size_t* allocated,
101 : OS::MemoryPermission access, void* hint) {
102 207 : const size_t msize = RoundUp(requested, AllocateAlignment());
103 207 : int prot = GetProtectionFromMemoryPermission(access);
104 : void* mbase = mmap(hint, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, kMmapFd,
105 207 : kMmapFdOffset);
106 207 : if (mbase == MAP_FAILED) return nullptr;
107 207 : *allocated = msize;
108 207 : return mbase;
109 : }
110 :
111 : // static
112 555566 : void* OS::ReserveRegion(size_t size, void* hint) {
113 : void* result =
114 : mmap(hint, size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
115 555566 : kMmapFd, kMmapFdOffset);
116 :
117 555568 : if (result == MAP_FAILED) return nullptr;
118 555544 : return result;
119 : }
120 :
121 : // static
122 494817 : void* OS::ReserveAlignedRegion(size_t size, size_t alignment, void* hint,
123 : size_t* allocated) {
124 : DCHECK_EQ(alignment % OS::AllocateAlignment(), 0);
125 : hint = AlignedAddress(hint, alignment);
126 : size_t request_size =
127 494817 : RoundUp(size + alignment, static_cast<intptr_t>(OS::AllocateAlignment()));
128 494820 : void* result = ReserveRegion(request_size, hint);
129 494821 : if (result == nullptr) {
130 12 : *allocated = 0;
131 12 : return nullptr;
132 : }
133 :
134 : uint8_t* base = static_cast<uint8_t*>(result);
135 494809 : uint8_t* aligned_base = RoundUp(base, alignment);
136 : DCHECK_LE(base, aligned_base);
137 :
138 : // Unmap extra memory reserved before and after the desired block.
139 494809 : if (aligned_base != base) {
140 1 : size_t prefix_size = static_cast<size_t>(aligned_base - base);
141 1 : OS::Free(base, prefix_size);
142 1 : request_size -= prefix_size;
143 : }
144 :
145 494809 : size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
146 : DCHECK_LE(aligned_size, request_size);
147 :
148 494809 : if (aligned_size != request_size) {
149 494809 : size_t suffix_size = request_size - aligned_size;
150 494809 : OS::Free(aligned_base + aligned_size, suffix_size);
151 : request_size -= suffix_size;
152 : }
153 :
154 : DCHECK(aligned_size == request_size);
155 :
156 494809 : *allocated = aligned_size;
157 494809 : return static_cast<void*>(aligned_base);
158 : }
159 :
160 : // static
161 1171369 : bool OS::CommitRegion(void* address, size_t size, bool is_executable) {
162 1171369 : int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
163 1171369 : if (MAP_FAILED == mmap(address, size, prot,
164 : MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, kMmapFd,
165 1171369 : kMmapFdOffset)) {
166 : return false;
167 : }
168 :
169 1171369 : return true;
170 : }
171 :
172 : // static
173 481250 : bool OS::UncommitRegion(void* address, size_t size) {
174 : return mmap(address, size, PROT_NONE,
175 : MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE | MAP_FIXED, kMmapFd,
176 481250 : kMmapFdOffset) != MAP_FAILED;
177 : }
178 :
179 : // static
180 540418 : bool OS::ReleaseRegion(void* address, size_t size) {
181 540418 : return munmap(address, size) == 0;
182 : }
183 :
184 : // static
185 109926 : bool OS::ReleasePartialRegion(void* address, size_t size) {
186 109926 : return munmap(address, size) == 0;
187 : }
188 :
189 : // static
190 4127 : bool OS::HasLazyCommits() { return true; }
191 :
192 0 : std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
193 : std::vector<SharedLibraryAddress> result;
194 : // This function assumes that the layout of the file is as follows:
195 : // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name]
196 : // If we encounter an unexpected situation we abort scanning further entries.
197 0 : FILE* fp = fopen("/proc/self/maps", "r");
198 0 : if (fp == nullptr) return result;
199 :
200 : // Allocate enough room to be able to store a full file name.
201 : const int kLibNameLen = FILENAME_MAX + 1;
202 0 : char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen));
203 :
204 : // This loop will terminate once the scanning hits an EOF.
205 : while (true) {
206 : uintptr_t start, end, offset;
207 : char attr_r, attr_w, attr_x, attr_p;
208 : // Parse the addresses and permission bits at the beginning of the line.
209 0 : if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break;
210 0 : if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break;
211 0 : if (fscanf(fp, "%" V8PRIxPTR, &offset) != 1) break;
212 :
213 : // Adjust {start} based on {offset}.
214 0 : start -= offset;
215 :
216 : int c;
217 0 : if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') {
218 : // Found a read-only executable entry. Skip characters until we reach
219 : // the beginning of the filename or the end of the line.
220 0 : do {
221 0 : c = getc(fp);
222 0 : } while ((c != EOF) && (c != '\n') && (c != '/') && (c != '['));
223 0 : if (c == EOF) break; // EOF: Was unexpected, just exit.
224 :
225 : // Process the filename if found.
226 0 : if ((c == '/') || (c == '[')) {
227 : // Push the '/' or '[' back into the stream to be read below.
228 0 : ungetc(c, fp);
229 :
230 : // Read to the end of the line. Exit if the read fails.
231 0 : if (fgets(lib_name, kLibNameLen, fp) == nullptr) break;
232 :
233 : // Drop the newline character read by fgets. We do not need to check
234 : // for a zero-length string because we know that we at least read the
235 : // '/' or '[' character.
236 0 : lib_name[strlen(lib_name) - 1] = '\0';
237 : } else {
238 : // No library name found, just record the raw address range.
239 : snprintf(lib_name, kLibNameLen, "%08" V8PRIxPTR "-%08" V8PRIxPTR, start,
240 0 : end);
241 : }
242 0 : result.push_back(SharedLibraryAddress(lib_name, start, end));
243 : } else {
244 : // Entry not describing executable data. Skip to end of line to set up
245 : // reading the next entry.
246 0 : do {
247 0 : c = getc(fp);
248 0 : } while ((c != EOF) && (c != '\n'));
249 0 : if (c == EOF) break;
250 : }
251 : }
252 0 : free(lib_name);
253 0 : fclose(fp);
254 0 : return result;
255 : }
256 :
257 0 : void OS::SignalCodeMovingGC() {
258 : // Support for ll_prof.py.
259 : //
260 : // The Linux profiler built into the kernel logs all mmap's with
261 : // PROT_EXEC so that analysis tools can properly attribute ticks. We
262 : // do a mmap with a name known by ll_prof.py and immediately munmap
263 : // it. This injects a GC marker into the stream of events generated
264 : // by the kernel and allows us to synchronize V8 code log and the
265 : // kernel log.
266 0 : long size = sysconf(_SC_PAGESIZE); // NOLINT(runtime/int)
267 0 : FILE* f = fopen(OS::GetGCFakeMMapFile(), "w+");
268 0 : if (f == nullptr) {
269 0 : OS::PrintError("Failed to open %s\n", OS::GetGCFakeMMapFile());
270 0 : OS::Abort();
271 : }
272 : void* addr = mmap(OS::GetRandomMmapAddr(), size, PROT_READ | PROT_EXEC,
273 0 : MAP_PRIVATE, fileno(f), 0);
274 : DCHECK_NE(MAP_FAILED, addr);
275 0 : OS::Free(addr, size);
276 0 : fclose(f);
277 0 : }
278 :
279 : } // namespace base
280 : } // namespace v8
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