esp32: Add core dump saving to flash feature

Complimentary changes:
1) Partition table definitions files with core dump partition
2) Special sub-type for core dump partition
3) Special version of spi_flash_xxx
4) espcoredump.py is script to get core dump from flash and print useful info
5) FreeRTOS API was extended to get tasks snapshots

components/spi_flash/include/esp_spi_flash.h

@@ -173,6 +173,56 @@ void spi_flash_munmap(spi_flash_mmap_handle_t handle);
  */
 void spi_flash_mmap_dump();
 
+/**
+ * @brief  Erase a range of flash sectors.
+ *
+ * @note This version of function is to be called from panic handler.
+ *       It does not use any OS primitives and IPC and implies that
+ *       only calling CPU is active.
+ *
+ * @param  start_address  Address where erase operation has to start.
+ *                                  Must be 4kB-aligned
+ * @param  size  Size of erased range, in bytes. Must be divisible by 4kB.
+ *
+ * @return esp_err_t
+ */
+esp_err_t spi_flash_erase_range_panic(size_t start_address, size_t size);
+
+
+/**
+ * @brief  Write data to Flash.
+ *
+ * @note This version of function is to be called from panic handler.
+ *       It does not use any OS primitives and IPC and implies that
+ *       only calling CPU is active.
+
+ * @note If source address is in DROM, this function will return
+ *       ESP_ERR_INVALID_ARG.
+ *
+ * @param  dest  destination address in Flash. Must be a multiple of 4 bytes.
+ * @param  src   pointer to the source buffer.
+ * @param  size  length of data, in bytes. Must be a multiple of 4 bytes.
+ *
+ * @return esp_err_t
+ */
+esp_err_t spi_flash_write_panic(size_t dest, const void *src, size_t size);
+
+
+/**
+ * @brief  Read data from Flash.
+ *
+ * @note This version of function is to be called from panic handler.
+ *       It does not use any OS primitives and IPC and implies that
+ *       only calling CPU is active.
+ *
+ * @param  src   source address of the data in Flash.
+ * @param  dest  pointer to the destination buffer
+ * @param  size  length of data
+ *
+ * @return esp_err_t
+ */
+esp_err_t spi_flash_read_panic(size_t src, void *dest, size_t size);
+
 #if CONFIG_SPI_FLASH_ENABLE_COUNTERS
 
 /**