From 605b51b84e622ce64ee77b066599c7b16d9d2c9d Mon Sep 17 00:00:00 2001
From: Pavel Labath <labath@google.com>
Date: Tue, 23 Feb 2016 13:56:30 +0000
Subject: Work around a stepping bug in arm64 android M

Summary:
On arm64, linux<=4.4 and Android<=M there is a bug, which prevents single-stepping from working when
the system comes back from suspend, because of incorrectly initialized CPUs. This did not really
affect Android<M, because it did not use software suspend, but it is a problem for M, which uses
suspend (doze) quite extensively.  Fortunately, it seems that the first CPU is not affected by
this bug, so this commit implements a workaround by forcing the inferior to execute on the first
cpu whenever we are doing single stepping.

While inside, I have moved the implementations of Resume() and SingleStep() to the thread class
(instead of process).

Reviewers: tberghammer, ovyalov

Subscribers: aemerson, rengolin, tberghammer, danalbert, srhines, lldb-commits

Differential Revision: http://reviews.llvm.org/D17509

llvm-svn: 261636
---
 .../Plugins/Process/Linux/NativeProcessLinux.cpp   | 43 +---------------------
 1 file changed, 2 insertions(+), 41 deletions(-)

(limited to 'lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp')

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index af875df4436..ea0972cf58c 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -2654,43 +2654,6 @@ NativeProcessLinux::WriteMemory(lldb::addr_t addr, const void *buf, size_t size,
     return error;
 }
 
-Error
-NativeProcessLinux::Resume (lldb::tid_t tid, uint32_t signo)
-{
-    Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_PROCESS));
-
-    if (log)
-        log->Printf ("NativeProcessLinux::%s() resuming thread = %"  PRIu64 " with signal %s", __FUNCTION__, tid,
-                                 Host::GetSignalAsCString(signo));
-
-
-
-    intptr_t data = 0;
-
-    if (signo != LLDB_INVALID_SIGNAL_NUMBER)
-        data = signo;
-
-    Error error = PtraceWrapper(PTRACE_CONT, tid, nullptr, (void*)data);
-
-    if (log)
-        log->Printf ("NativeProcessLinux::%s() resuming thread = %"  PRIu64 " result = %s", __FUNCTION__, tid, error.Success() ? "true" : "false");
-    return error;
-}
-
-Error
-NativeProcessLinux::SingleStep(lldb::tid_t tid, uint32_t signo)
-{
-    intptr_t data = 0;
-
-    if (signo != LLDB_INVALID_SIGNAL_NUMBER)
-        data = signo;
-
-    // If hardware single-stepping is not supported, we just do a continue. The breakpoint on the
-    // next instruction has been setup in NativeProcessLinux::Resume.
-    return PtraceWrapper(SupportHardwareSingleStepping() ? PTRACE_SINGLESTEP : PTRACE_CONT,
-            tid, nullptr, (void*)data);
-}
-
 Error
 NativeProcessLinux::GetSignalInfo(lldb::tid_t tid, void *siginfo)
 {
@@ -2979,16 +2942,14 @@ NativeProcessLinux::ResumeThread(NativeThreadLinux &thread, lldb::StateType stat
     {
     case eStateRunning:
     {
-        thread.SetRunning();
-        const auto resume_result = Resume(thread.GetID(), signo);
+        const auto resume_result = thread.Resume(signo);
         if (resume_result.Success())
             SetState(eStateRunning, true);
         return resume_result;
     }
     case eStateStepping:
     {
-        thread.SetStepping();
-        const auto step_result = SingleStep(thread.GetID(), signo);
+        const auto step_result = thread.SingleStep(signo);
         if (step_result.Success())
             SetState(eStateRunning, true);
         return step_result;
-- 
cgit v1.2.3