Files
sdk/runtime/vm/signal_handler_android.cc
T
Vyacheslav Egorov b089d4f004 Work around a kernel bug on Android.
Kernel does not clear If-Then execution state bits when entering ARM signal handler which violates requirements imposed by ARM architecture reference. Some CPUs look at these bits even while in ARM mode which causes them
to skip some instructions in the prologue of the signal handler.

To work around the issue we insert enough NOPs in the prologue to ensure that no actual instructions are skipped and then branch to the actual signal handler.

For the kernel patch that fixes the issue see: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6ecf830e5029598732e04067e325d946097519cb

This causes sporadic crashes with SIGILL on some testing devices (e.g. Nexus 7).

R=fschneider@google.com
BUG=

Review URL: https://codereview.chromium.org/1940883002 .
2016-05-02 19:12:48 +02:00

129 lines
3.3 KiB
C++

// Copyright (c) 2013, 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/globals.h"
#include "vm/simulator.h"
#include "vm/signal_handler.h"
#if defined(TARGET_OS_ANDROID)
namespace dart {
uintptr_t SignalHandler::GetProgramCounter(const mcontext_t& mcontext) {
uintptr_t pc = 0;
#if defined(HOST_ARCH_IA32)
pc = static_cast<uintptr_t>(mcontext.gregs[REG_EIP]);
#elif defined(HOST_ARCH_X64)
pc = static_cast<uintptr_t>(mcontext.gregs[REG_RIP]);
#elif defined(HOST_ARCH_ARM)
pc = static_cast<uintptr_t>(mcontext.arm_pc);
#elif defined(HOST_ARCH_ARM64)
pc = static_cast<uintptr_t>(mcontext.pc);
#else
#error Unsupported architecture.
#endif // HOST_ARCH_...
return pc;
}
uintptr_t SignalHandler::GetFramePointer(const mcontext_t& mcontext) {
uintptr_t fp = 0;
#if defined(HOST_ARCH_IA32)
fp = static_cast<uintptr_t>(mcontext.gregs[REG_EBP]);
#elif defined(HOST_ARCH_X64)
fp = static_cast<uintptr_t>(mcontext.gregs[REG_RBP]);
#elif defined(HOST_ARCH_ARM)
fp = static_cast<uintptr_t>(mcontext.arm_fp);
#elif defined(HOST_ARCH_ARM64)
fp = static_cast<uintptr_t>(mcontext.regs[29]);
#else
#error Unsupported architecture.
#endif // HOST_ARCH_...
return fp;
}
uintptr_t SignalHandler::GetCStackPointer(const mcontext_t& mcontext) {
uintptr_t sp = 0;
#if defined(HOST_ARCH_IA32)
sp = static_cast<uintptr_t>(mcontext.gregs[REG_ESP]);
#elif defined(HOST_ARCH_X64)
sp = static_cast<uintptr_t>(mcontext.gregs[REG_RSP]);
#elif defined(HOST_ARCH_ARM)
sp = static_cast<uintptr_t>(mcontext.arm_sp);
#elif defined(HOST_ARCH_ARM64)
sp = static_cast<uintptr_t>(mcontext.sp);
#else
#error Unsupported architecture.
#endif // HOST_ARCH_...
return sp;
}
uintptr_t SignalHandler::GetDartStackPointer(const mcontext_t& mcontext) {
uintptr_t sp = 0;
#if defined(HOST_ARCH_IA32)
sp = static_cast<uintptr_t>(mcontext.gregs[REG_ESP]);
#elif defined(HOST_ARCH_X64)
sp = static_cast<uintptr_t>(mcontext.gregs[REG_RSP]);
#elif defined(HOST_ARCH_ARM)
sp = static_cast<uintptr_t>(mcontext.arm_sp);
#elif defined(HOST_ARCH_ARM64)
sp = static_cast<uintptr_t>(mcontext.regs[19]);
#else
#error Unsupported architecture.
#endif // HOST_ARCH_...
return sp;
}
uintptr_t SignalHandler::GetLinkRegister(const mcontext_t& mcontext) {
uintptr_t lr = 0;
#if defined(HOST_ARCH_IA32)
lr = 0;
#elif defined(HOST_ARCH_X64)
lr = 0;
#elif defined(HOST_ARCH_ARM)
lr = static_cast<uintptr_t>(mcontext.arm_lr);
#elif defined(HOST_ARCH_ARM64)
lr = static_cast<uintptr_t>(mcontext.regs[30]);
#else
#error Unsupported architecture.
#endif // HOST_ARCH_...
return lr;
}
void SignalHandler::InstallImpl(SignalAction action) {
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_sigaction = action;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_RESTART | SA_SIGINFO;
int r = sigaction(SIGPROF, &act, NULL);
ASSERT(r == 0);
}
void SignalHandler::Remove() {
// Ignore future SIGPROF signals because by default SIGPROF will terminate
// the process and we may have some signals in flight.
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = SIG_IGN;
sigemptyset(&act.sa_mask);
int r = sigaction(SIGPROF, &act, NULL);
ASSERT(r == 0);
}
} // namespace dart
#endif // defined(TARGET_OS_ANDROID)