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8368691a2a
Bug 1463035 exists to remove it entirely, because as mentioned in bug 1238661 comment 4, we don't actually need this workaround anymore. But that bug has been blocked for a while because the Android emulator images we use for testing, for some reason, use a kernel older than any real device using the same version of Android would use. Let's however fix the problems it causes with GCC on non-Android ARM Linux by making it Android-only, rather than removing it entirely. Differential Revision: https://phabricator.services.mozilla.com/D24134 --HG-- extra : moz-landing-system : lando
39 lines
1.2 KiB
C++
39 lines
1.2 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_LinuxSignal_h
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#define mozilla_LinuxSignal_h
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namespace mozilla {
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#if defined(__arm__) && defined(__ANDROID__)
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// Some (old) Linux kernels on ARM have a bug where a signal handler
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// can be called without clearing the IT bits in CPSR first. The result
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// is that the first few instructions of the handler could be skipped,
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// ultimately resulting in crashes. To workaround this bug, the handler
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// on ARM is a trampoline that starts with enough NOP instructions, so
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// that even if the IT bits are not cleared, only the NOP instructions
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// will be skipped over.
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template <void (*H)(int, siginfo_t*, void*)>
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__attribute__((naked)) void SignalTrampoline(int aSignal, siginfo_t* aInfo,
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void* aContext) {
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asm volatile("nop; nop; nop; nop" : : : "memory");
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asm volatile("b %0" : : "X"(H) : "memory");
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}
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# define MOZ_SIGNAL_TRAMPOLINE(h) (mozilla::SignalTrampoline<h>)
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#else // __arm__
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# define MOZ_SIGNAL_TRAMPOLINE(h) (h)
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#endif // __arm__
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} // namespace mozilla
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#endif // mozilla_LinuxSignal_h
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