From 34a21912aec8432c1c1b80feb5317d22b24aaf0b Mon Sep 17 00:00:00 2001
From: rkx1209 <rkx1209dev@gmail.com>
Date: Tue, 3 Apr 2018 17:18:12 +0900
Subject: [PATCH] Add cpu dump function after trigerring SEGV

---
 ARMv8/ARMv8.cpp | 14 +++++++-------
 Cpu.cpp         |  2 +-
 Main.cpp        | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/ARMv8/ARMv8.cpp b/ARMv8/ARMv8.cpp
index ebb10b6..7ca506f 100644
--- a/ARMv8/ARMv8.cpp
+++ b/ARMv8/ARMv8.cpp
@@ -22,21 +22,21 @@ void RunLoop() {
 
 void Dump() {
         int cnt = 1;
-        debug_print ("CPU Dump:\n");
+        ns_print ("CPU Dump:\n");
         for (int r = 0; r < GPR_DUMMY; r++) {
                 if (!X(r))
                         continue;
                 if (r == GPR_LR)
-                        debug_print ("LR:\t");
+                        ns_print ("LR:\t");
                 else if (r == GPR_SP)
-                        debug_print ("SP:\t");
+                        ns_print ("SP:\t");
                 else
-                        debug_print ("X%d:\t", r);
-                debug_print ("0x%016lx%c", X(r), cnt % 3 == 0 ? '\n' : '\t');
+                        ns_print ("X%d:\t", r);
+                ns_print ("0x%016lx%c", X(r), cnt % 3 == 0 ? '\n' : '\t');
                 cnt++;
         }
-        debug_print ("PC:\t0x%016lx\n", PC);
-        debug_print ("NZCV:\t0x%016lx\n", NZCV);
+        ns_print ("PC:\t0x%016lx\n", PC);
+        ns_print ("NZCV:\t0x%016lx\n", NZCV);
 }
 
 static uint64_t counter;
diff --git a/Cpu.cpp b/Cpu.cpp
index a0b8f62..ace7c0e 100644
--- a/Cpu.cpp
+++ b/Cpu.cpp
@@ -29,7 +29,7 @@ State GetState() {
 }
 
 void DumpMachine() {
-        ARMv8::Dump ();
+        //ARMv8::Dump ();
         if (TraceOut)
                 ARMv8::DumpJson (TraceOut);
 }
diff --git a/Main.cpp b/Main.cpp
index b5d6c1c..82fb2a1 100644
--- a/Main.cpp
+++ b/Main.cpp
@@ -1,5 +1,6 @@
 /* nsemu - LGPL - Copyright 2017 rkx1209<rkx1209dev@gmail.com> */
 #include "Nsemu.hpp"
+#include <csignal>
 #include "optionparser.h"
 using namespace std;
 struct Arg : public option::Arg {
@@ -88,6 +89,14 @@ const option::Descriptor usage[] =
 	{ 0, 0, nullptr, nullptr, nullptr, nullptr }
 };
 
+static void SignalHandler(int sig, siginfo_t* sig_info, void* sig_data) {
+        if(sig == SIGSEGV) {
+                ns_print ("SEGV: %p\n", sig_info->si_addr );
+                ARMv8::Dump();
+                _Exit(-1);
+        }
+}
+
 int main(int argc, char **argv) {
 	Nsemu::create ();
 	Nsemu *nsemu = Nsemu::get_instance ();
@@ -141,6 +150,16 @@ printUsage:
 		              goto printUsage;
 		}
 	}
+        /* ### Register SEGV handler for debugging ### */
+        struct sigaction segv_act;
+        sigemptyset(&segv_act.sa_mask);
+        sigaddset(&segv_act.sa_mask, SIGSEGV);
+        segv_act.sa_sigaction = SignalHandler;
+        segv_act.sa_flags     = SA_SIGINFO|SA_RESTART|SA_ONSTACK;
+        if( sigaction( SIGSEGV, &segv_act, NULL ) == -1 ){
+                ns_abort ("Failed to set my signal handler.\n");
+        }
+
         Banner ();
 	nsemu->BootUp (parse.nonOption (0));
 	Nsemu::destroy ();