Bug 1463035 - Remove MOZ_SIGNAL_TRAMPOLINE. r=jchen
☠☠ backed out by 0ee7d4aa1799 ☠ ☠
authorMike Hommey <mh+mozilla@glandium.org>
Mon, 21 May 2018 12:04:22 +0900
changeset 475938 98e368b5c4beb0a183b1260236f47e0c5937d9a8
parent 475937 649acbb993c3e469380692e22f276e23707606de
child 475939 5e5ef53eee5b69f9be604029afa46ba0afb75966
push id1757
push userffxbld-merge
push dateFri, 24 Aug 2018 17:02:43 +0000
treeherdermozilla-release@736023aebdb1 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersjchen
bugs1463035, 1238661
milestone62.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1463035 - Remove MOZ_SIGNAL_TRAMPOLINE. r=jchen For some reason, GNU as is not happy with the assembly generated after bug 1238661 anymore on Debian armel. OTOH, as mentioned in bug 1238661 comment 4, we actually don't need this workaround anymore, so let's just kill it.
mfbt/LinuxSignal.h
mfbt/moz.build
tools/profiler/core/platform-linux-android.cpp
deleted file mode 100644
--- a/mfbt/LinuxSignal.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_LinuxSignal_h
-#define mozilla_LinuxSignal_h
-
-namespace mozilla {
-
-#if defined(__arm__)
-
-// Some (old) Linux kernels on ARM have a bug where a signal handler
-// can be called without clearing the IT bits in CPSR first. The result
-// is that the first few instructions of the handler could be skipped,
-// ultimately resulting in crashes. To workaround this bug, the handler
-// on ARM is a trampoline that starts with enough NOP instructions, so
-// that even if the IT bits are not cleared, only the NOP instructions
-// will be skipped over.
-
-template <void (*H)(int, siginfo_t*, void*)>
-__attribute__((naked)) void
-SignalTrampoline(int aSignal, siginfo_t* aInfo, void* aContext)
-{
-  asm volatile (
-    "nop; nop; nop; nop"
-    : : : "memory");
-
-  asm volatile (
-    "b %0"
-    :
-    : "X"(H)
-    : "memory");
-}
-
-# define MOZ_SIGNAL_TRAMPOLINE(h) (mozilla::SignalTrampoline<h>)
-
-#else // __arm__
-
-# define MOZ_SIGNAL_TRAMPOLINE(h) (h)
-
-#endif // __arm__
-
-} // namespace mozilla
-
-#endif // mozilla_LinuxSignal_h
--- a/mfbt/moz.build
+++ b/mfbt/moz.build
@@ -117,20 +117,16 @@ EXPORTS["double-conversion"] = [
 LOCAL_INCLUDES += [
     '/mfbt/double-conversion',
 ]
 
 if CONFIG['OS_ARCH'] == 'WINNT':
     EXPORTS.mozilla += [
         'WindowsVersion.h',
     ]
-elif CONFIG['OS_ARCH'] == 'Linux':
-    EXPORTS.mozilla += [
-        'LinuxSignal.h',
-    ]
 
 UNIFIED_SOURCES += [
     'Assertions.cpp',
     'ChaosMode.cpp',
     'double-conversion/double-conversion/bignum-dtoa.cc',
     'double-conversion/double-conversion/bignum.cc',
     'double-conversion/double-conversion/cached-powers.cc',
     'double-conversion/double-conversion/diy-fp.cc',
--- a/tools/profiler/core/platform-linux-android.cpp
+++ b/tools/profiler/core/platform-linux-android.cpp
@@ -55,17 +55,16 @@
 #ifdef __GLIBC__
 #include <execinfo.h>   // backtrace, backtrace_symbols
 #endif  // def __GLIBC__
 #include <strings.h>    // index
 #include <errno.h>
 #include <stdarg.h>
 
 #include "prenv.h"
-#include "mozilla/LinuxSignal.h"
 #include "mozilla/PodOperations.h"
 #include "mozilla/DebugOnly.h"
 
 #include <string.h>
 #include <list>
 
 using namespace mozilla;
 
@@ -272,17 +271,17 @@ Sampler::Sampler(PSLockRef aLock)
 
   // NOTE: We don't initialize LUL here, instead initializing it in
   // SamplerThread's constructor. This is because with the
   // profiler_suspend_and_sample_thread entry point, we want to be able to
   // sample without waiting for LUL to be initialized.
 
   // Request profiling signals.
   struct sigaction sa;
-  sa.sa_sigaction = MOZ_SIGNAL_TRAMPOLINE(SigprofHandler);
+  sa.sa_sigaction = SigprofHandler;
   sigemptyset(&sa.sa_mask);
   sa.sa_flags = SA_RESTART | SA_SIGINFO;
   if (sigaction(SIGPROF, &sa, &mOldSigprofHandler) != 0) {
     MOZ_CRASH("Error installing SIGPROF handler in the profiler");
   }
 }
 
 void