Vyacheslav Egorov
c111f693c7
Freelist implementation was trying to mark pages executable (RX) which does not respect possibility that it is working with RW mapping which can't be directly marked as executable. It needed to use RO permission instead if dual mapping is enabled. This CL consolidates all code mentioning RX permission in one place: VirtualMemory::WriteProtectCode so that we avoid this mistake in the future. R=kustermann@google.com TEST=tested by doing large reloads which cause more churn in code space Change-Id: If99692cac3ce3ff54b907e4c43d7f26bae7439ff Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/435860 Commit-Queue: Martin Kustermann <kustermann@google.com> Auto-Submit: Slava Egorov <vegorov@google.com> Reviewed-by: Martin Kustermann <kustermann@google.com>
65 lines
2.3 KiB
C++
65 lines
2.3 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
#include "vm/code_patcher.h"
|
|
#include "vm/cpu.h"
|
|
#include "vm/instructions.h"
|
|
#include "vm/object.h"
|
|
#include "vm/virtual_memory.h"
|
|
|
|
namespace dart {
|
|
|
|
#if defined(DART_HOST_OS_MACOS) || defined(DART_HOST_OS_MACOS_IOS)
|
|
// On iOS even with debugger attached we must still guarantee that memory
|
|
// is never executable and writable at the same time. On Mac OS X
|
|
// com.apple.security.cs.allow-jit entitlement allows WX memory regions to be
|
|
// created - but we should not rely on this entitlement to be present.
|
|
static constexpr bool kShouldWriteProtectCodeByDefault = true;
|
|
#else
|
|
static constexpr bool kShouldWriteProtectCodeByDefault = false;
|
|
#endif
|
|
|
|
DEFINE_FLAG(bool,
|
|
write_protect_code,
|
|
kShouldWriteProtectCodeByDefault,
|
|
"Write protect jitted code");
|
|
|
|
#if defined(TARGET_ARCH_IA32)
|
|
WritableInstructionsScope::WritableInstructionsScope(uword address,
|
|
intptr_t size)
|
|
: address_(address), size_(size) {
|
|
if (FLAG_write_protect_code) {
|
|
VirtualMemory::Protect(reinterpret_cast<void*>(address), size,
|
|
VirtualMemory::kReadWrite);
|
|
}
|
|
}
|
|
|
|
WritableInstructionsScope::~WritableInstructionsScope() {
|
|
if (FLAG_write_protect_code) {
|
|
VirtualMemory::WriteProtectCode(reinterpret_cast<void*>(address_), size_);
|
|
}
|
|
}
|
|
#endif // defined(TARGET_ARCH_IA32)
|
|
|
|
bool MatchesPattern(uword end, const int16_t* pattern, intptr_t size) {
|
|
// When breaking within generated code in GDB, it may overwrite individual
|
|
// instructions with trap instructions, which can cause this test to fail.
|
|
//
|
|
// Ignoring trap instructions would work well enough within GDB alone, but it
|
|
// doesn't work in RR, because the check for the trap instruction itself will
|
|
// cause replay to diverge from the original record.
|
|
if (FLAG_support_rr) return true;
|
|
|
|
uint8_t* bytes = reinterpret_cast<uint8_t*>(end - size);
|
|
for (intptr_t i = 0; i < size; i++) {
|
|
int16_t val = pattern[i];
|
|
if ((val >= 0) && (val != bytes[i])) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
} // namespace dart
|