Core dump analysis improvements

 * ARM
   * Provide MSP and PSP
   * Provide FreeRTOS task info
   * Profide target specification XML (extra regs and FPU / no FPU Cortex cores)
 * ESP32
   * Use uxTaskGetSystemState instead of uxTaskGetTaskHandles
 * General cleanup and refactoring

CL: Core dump analysis improvements

PUBLISHED_FROM=3297ffb2e6069a3a6a598367273bc2183063cf1e

include/FreeRTOSConfigCommon.h

@@ -64,7 +64,7 @@
 
 #define configUSE_MALLOC_FAILED_HOOK 0
 #define configUSE_TICKLESS_IDLE 0
-#define configUSE_TRACE_FACILITY 0
+#define configUSE_TRACE_FACILITY 1
 #define configUSE_PORT_OPTIMISED_TASK_SELECTION 1
 #define configAPPLICATION_ALLOCATED_HEAP 0
 #define configUSE_TASK_NOTIFICATIONS 1

include/mgos_freertos.h

@@ -8,6 +8,8 @@
 #include <stdbool.h>
 
 #include "FreeRTOS.h"
+#include "queue.h"
+#include "task.h"
 
 #include "mgos_init.h"
 
@@ -19,6 +21,12 @@ void mgos_freertos_run_mgos_task(bool start_scheduler);
 
 extern enum mgos_init_result mgos_freertos_pre_init(void);
 
+void mgos_freertos_core_dump(void);
+
+// This function extracts registers from the task's stack frame
+// and populates GDB stack frame.
+size_t mgos_freertos_extract_regs(StackType_t *sp, void *buf, size_t buf_size);
+
 #ifdef __cplusplus
 }
 #endif

src/cmsis/mgos_arm_regs.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2014-2018 Cesanta Software Limited
+ * All rights reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the ""License"");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an ""AS IS"" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+
+#include "arm_exc.h"
+#include "mgos_freertos.h"
+
+// This uses the same logic as xPortPendSVHandler does when switching tasks.
+size_t mgos_freertos_extract_regs(StackType_t *sp, void *buf, size_t buf_size) {
+  struct arm_gdb_reg_file *rf = (struct arm_gdb_reg_file *) buf;
+  if (buf_size < sizeof(*rf)) return 0;
+  // ldmia r0!, {r4-r11, r14}
+  rf->r[4] = *sp++;
+  rf->r[5] = *sp++;
+  rf->r[6] = *sp++;
+  rf->r[7] = *sp++;
+  rf->r[8] = *sp++;
+  rf->r[9] = *sp++;
+  rf->r[10] = *sp++;
+  rf->r[11] = *sp++;
+  uint32_t exc_lr = *sp++;
+#if __FPU_PRESENT
+  // Is the task using the FPU context?  If so, pop the high vfp registers too.
+  bool fpu_used = (exc_lr & 0x10) == 0;
+  if (fpu_used) {
+    // vldmiaeq r0!, {s16-s31}
+    memcpy((void *) &rf->d[8], sp, 16 * 4);
+    sp += 16;
+  }
+#endif
+  // After this we have standard exception frame.
+  rf->r[0] = *sp++;
+  rf->r[1] = *sp++;
+  rf->r[2] = *sp++;
+  rf->r[3] = *sp++;
+  rf->r[12] = *sp++;
+  rf->lr = *sp++;
+  rf->pc = *sp++;
+  rf->xpsr = *sp++;
+#if __FPU_PRESENT
+  if (fpu_used) {
+    memcpy((void *) &rf->d[0], sp, 16 * 4);  // s0 - s15
+    sp += 16;
+    rf->fpscr = *sp++;
+    sp++;  // reserved
+  }
+#else
+  (void) exc_lr;
+#endif
+  rf->sp = (uint32_t) sp;
+  rf->psp = (uint32_t) sp;
+  // msp? do we need it?
+  return sizeof(*rf);
+}

src/mgos_freertos.c

@@ -270,6 +270,8 @@ void mgos_freertos_run_mgos_task(bool start_scheduler) {
 
   mgos_app_preinit();
 
+  mgos_cd_register_section_writer(mgos_freertos_core_dump);
+
   s_mgos_mux = xSemaphoreCreateRecursiveMutex();
   s_mg_poll_timer = xTimerCreate("mg_poll", 10, pdFALSE /* reload */, 0,
                                  mgos_mg_poll_timer_cb);

src/mgos_freertos_core_dump.c

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2014-2019 Cesanta Software Limited
+ * All rights reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the ""License"");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an ""AS IS"" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mgos_freertos.h"
+
+#include "common/platform.h"
+
+#include "mgos_core_dump.h"
+#include "mgos_utils.h"
+
+// TODO(rojer): Multi-processor support.
+
+extern TaskHandle_t pxCurrentTCB;
+
+void mgos_freertos_core_dump(void) {
+  uint32_t unused_runtime;
+  TaskStatus_t tss[16];
+  mgos_cd_puts(",\r\n\"freertos\":{\"tasks\":[");
+  UBaseType_t n = uxTaskGetSystemState(tss, ARRAY_SIZE(tss), &unused_runtime);
+  for (UBaseType_t i = 0; i < n; i++) {
+    const TaskStatus_t *ts = &tss[i];
+    if (i > 0) mgos_cd_puts(",");
+    // Topt of stack pointer is the first member of the task structure.
+    StackType_t *pxTopOfStack = *((StackType_t **) ts->xHandle);
+    mgos_cd_puts("\r\n");
+    mgos_cd_printf(
+        "{\"h\":%lu,\"n\":\"%s\",\"st\":%lu,"
+        "\"cpri\":%lu,\"bpri\":%lu,\"sb\":%lu,\"sp\":%lu",
+        (unsigned long) ts->xHandle, ts->pcTaskName,
+        (unsigned long) ts->eCurrentState,
+        (unsigned long) ts->uxCurrentPriority,
+        (unsigned long) ts->uxBasePriority, (unsigned long) ts->pxStackBase,
+        (unsigned long) pxTopOfStack);
+    if (ts->xHandle != pxCurrentTCB) {
+      uint32_t buf[128];  // Surely this will be enough.
+      memset(buf, 0, sizeof(buf));
+      size_t regs_size =
+          mgos_freertos_extract_regs(pxTopOfStack, &buf, sizeof(buf));
+      if (regs_size > 0) {
+        mgos_cd_write_section("regs", buf, regs_size);
+      }
+    } else {
+      // For running task current backtrace will be used.
+    }
+    mgos_cd_puts("}");
+  }
+  mgos_cd_printf("\r\n],\"cur\":%lu}", (unsigned long) pxCurrentTCB);
+}