Add save call stack in RTC memory in case of crash

Add save call stack in RTC memory in case of crash, command ``Status 12`` to dump the stack (#7114, #5883)

tasmota/CHANGELOG.md

@@ -3,6 +3,7 @@
 ### 7.1.2.2 20191206
 
 - Add command ``SerialConfig 0..23`` or ``SerialConfig 8N1`` to select Serial Config (#7108)
+- Add save call stack in RTC memory in case of crash, command ``Status 12`` to dump the stack
 
 ### 7.1.2.1 20191206
 

tasmota/i18n.h

@@ -208,6 +208,7 @@
   #define D_STATUS9_MARGIN "PTH"
   #define D_STATUS10_SENSOR "SNS"
   #define D_STATUS11_STATUS "STS"
+  #define D_STATUS12_STATUS "STK"
 #define D_CMND_STATE "State"
 #define D_CMND_POWER "Power"
 #define D_CMND_FANSPEED "FanSpeed"

tasmota/support_command.ino

@@ -483,6 +483,13 @@ void CmndStatus(void)
     MqttPublishPrefixTopic_P(option, PSTR(D_CMND_STATUS "11"));
   }
 
+  if ((0 == payload) || (12 == payload)) {
+    Response_P(PSTR("{\"" D_CMND_STATUS D_STATUS12_STATUS "\":"));
+    CrashDump();
+    ResponseJsonEnd();
+    MqttPublishPrefixTopic_P(option, PSTR(D_CMND_STATUS "12"));
+  }
+
 #ifdef USE_SCRIPT_STATUS
   if (bitRead(Settings.rule_enabled, 0)) Run_Scripter(">U",2,mqtt_data);
 #endif
@@ -564,6 +571,9 @@ void CmndRestart(void)
     restart_flag = 2;
     ResponseCmndChar(D_JSON_RESTARTING);
     break;
+  case -1:
+    CmndCrash();    // force a crash
+    break;
   case 99:
     AddLog_P(LOG_LEVEL_INFO, PSTR(D_LOG_APPLICATION D_RESTARTING));
     EspRestart();

tasmota/support_crash_recorder.ino

@@ -0,0 +1,78 @@
+/*
+  support_crash_recorder.ino - record the call stack in RTC in cas of crash
+
+  Copyright (C) 2019  Stephan Hadinger, Theo Arends,
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+const uint32_t dump_max_len = 63;                   // dump only 64 call addresses
+
+/**
+ * Save crash information in RTC memory
+ * This function is called automatically if ESP8266 suffers an exception
+ * It should be kept quick / consise to be able to execute before hardware wdt may kick in
+ */
+extern "C" void custom_crash_callback(struct rst_info * rst_info, uint32_t stack, uint32_t stack_end ) {
+  uint32_t addr_written = 0;      // how many addresses have we already written in RTC
+  uint32_t value;                 // 4 bytes buffer to write to RTC
+
+  for (uint32_t i = stack; i < stack_end; i += 4) {
+    value = *((uint32_t*) i);     // load value from stack
+    if ((value >= 0x40000000) && (value < 0x40300000)) {  // keep only addresses in code area
+      ESP.rtcUserMemoryWrite(addr_written, (uint32_t*)&value, sizeof(value));
+      addr_written++;
+      if (addr_written >= dump_max_len) { break; }        // we store only 63 addresses
+    }
+  }
+  // fill the rest of RTC with the amount of addresses
+  value = addr_written;
+  while (addr_written < dump_max_len +1) {
+    ESP.rtcUserMemoryWrite(addr_written++, (uint32_t*)&value, sizeof(value));
+  }
+}
+
+// Generate a crash to test the crash recorder
+void CmndCrash(void)
+{
+  volatile uint32_t dummy;
+  dummy = *((uint32_t*) 0x00000000);
+}
+
+// Clear the RTC dump counter when we do a normal reboot, this avoids garbage data to stay in RTC
+void CrashDumpClear(void) {
+  uint32_t value = 0;
+  ESP.rtcUserMemoryWrite(dump_max_len, (uint32_t*)&value, sizeof(value));
+}
+
+/*********************************************************************************************\
+ * CmndCrashDump - dump the crash history - called by `Status 12`
+\*********************************************************************************************/
+void CrashDump(void)
+{
+  ResponseAppend_P(PSTR("{\"call_chain\":["));
+
+  uint32_t value;
+  ESP.rtcUserMemoryRead(dump_max_len, (uint32_t*)&value, sizeof(value));
+  uint32_t count = value & 0x3F;
+
+  for (uint32_t i = 0; i < count; i++) {
+    ESP.rtcUserMemoryRead(i, (uint32_t*)&value, sizeof(value));
+    if ((value >= 0x40000000) && (value < 0x40300000)) {
+      if (i > 0) { ResponseAppend_P(PSTR(",")); }
+      ResponseAppend_P(PSTR("\"%08x\""), value);
+    }
+  }
+  ResponseAppend_P(PSTR("]}"));
+}

tasmota/support_wifi.ino

@@ -617,6 +617,7 @@ void WifiShutdown(void)
 void EspRestart(void)
 {
   WifiShutdown();
+  CrashDumpClear();           // Clear the stack dump in RTC
 //  ESP.restart();            // This results in exception 3 on restarts on core 2.3.0
   ESP.reset();
 }

tasmota/tasmota.h

@@ -131,7 +131,7 @@ const uint32_t SOFT_BAUDRATE = 9600;        // Default software serial baudrate
 const uint32_t APP_BAUDRATE = 115200;       // Default serial baudrate
 const uint32_t SERIAL_POLLING = 100;        // Serial receive polling in ms
 const uint32_t ZIGBEE_POLLING = 100;        // Serial receive polling in ms
-const uint8_t MAX_STATUS = 11;              // Max number of status lines
+const uint8_t MAX_STATUS = 12;              // Max number of status lines
 
 const uint32_t START_VALID_TIME = 1451602800;  // Time is synced and after 2016-01-01