Add in postmortem stack dump hooks

When a crash occurs while in the second stack, dump the BSSL stack and then also the stack that it was called from (either cont or sys).
esp8266 · devyte · Nov 15, 2018 · Sep 25, 2018 · Sep 25, 2018 · Sep 25, 2018
commit ec6ccdc507bc666c2fa982942202cdf08b070551
diff --git a/cores/esp8266/core_esp8266_postmortem.c b/cores/esp8266/core_esp8266_postmortem.c
@@ -30,6 +30,11 @@
 #include "pgmspace.h"
 #include "gdb_hooks.h"
 
+// From BearSSLThunks.c
+extern uint32_t br_thunk_get_stack_top();
+extern uint32_t br_thunk_get_stack_bot();
+extern uint32_t br_thunk_get_cont_sp();
+
 extern void __real_system_restart_local();
 
 // These will be pointers to PROGMEM const strings
@@ -147,6 +152,15 @@ void __wrap_system_restart_local() {
         offset = 0x10;
     }
 
+    if (sp > br_thunk_get_stack_bot() && sp <= br_thunk_get_stack_top()) {
+        // BearSSL we dump the BSSL second stack and then reset SP back to the main cont stack
+        ets_printf_P("\nctx: bearssl \n");
+        ets_printf_P("sp: %08x end: %08x offset: %04x\n", sp, br_thunk_get_stack_top(), offset);
+        print_stack(sp + offset, br_thunk_get_stack_top());
+        offset = 0; // No offset needed anymore, the exception info was stored in the bssl stack
+        sp = br_thunk_get_cont_sp();
+    }
+
     if (sp > cont_stack_start && sp < cont_stack_end) {
         ets_printf_P("\nctx: cont \n");
         stack_end = cont_stack_end;

diff --git a/libraries/ESP8266WiFi/src/BearSSLThunks.c b/libraries/ESP8266WiFi/src/BearSSLThunks.c
@@ -29,9 +29,10 @@
 
 static uint32_t *_stackPtr = NULL;
 static uint32_t *_stackTop = NULL;
+static uint32_t *_saveStack = NULL;  /* Saved A1 while in BearSSL */
 static uint32_t _refcnt = 0;
 
-#define _stackSize (4500/4)
+#define _stackSize (4600/4)
 #define _stackPaint 0xdeadbeef
 
 /* Add a reference, and allocate the stack if necessary */
@@ -44,6 +45,7 @@ void br_thunk_add_ref()
     for (int i=0; i < _stackSize; i++) {
       _stackPtr[i] = _stackPaint;
     }
+    _saveStack = NULL;
   }
 }
 
@@ -59,9 +61,27 @@ void br_thunk_del_ref()
     free(_stackPtr);
     _stackPtr = NULL;
     _stackTop = NULL;
+    _saveStack = NULL;
   }
 }
 
+/* Simple accessor functions used by postmortem */
+uint32_t br_thunk_get_refcnt() {
+  return _refcnt;
+}
+
+uint32_t br_thunk_get_stack_top() {
+  return (uint32_t)_stackTop;
+}
+
+uint32_t br_thunk_get_stack_bot() {
+  return (uint32_t)_stackPtr;
+}
+
+uint32_t br_thunk_get_cont_sp() {
+  return (uint32_t)_saveStack;
+}
+
 /* Return the number of bytes ever used since the stack was created */
 uint32_t br_thunk_get_max_usage()
 {
@@ -79,10 +99,6 @@ uint32_t br_thunk_get_max_usage()
 }
 
 __asm("\n\
-.data\n\
-.align 4\n\
-_saveStack: .word 0x00000000\n\
-\n\
 .text\n\
 .literal_position\n\
 \n\

diff --git a/libraries/ESP8266WiFi/src/BearSSLThunks.h b/libraries/ESP8266WiFi/src/BearSSLThunks.h
@@ -33,6 +33,11 @@ extern "C" {
 
 extern void br_thunk_add_ref();
 extern void br_thunk_del_ref();
+
+extern uint32_t br_thunk_get_refcnt();
+extern uint32_t br_thunk_get_stack_top();
+extern uint32_t br_thunk_get_stack_bot();
+extern uint32_t br_thunk_get_cont_sp();
 extern uint32_t br_thunk_get_max_usage();
 
 extern unsigned char *thunk_br_ssl_engine_recvapp_buf( const br_ssl_engine_context *cc, size_t *len);