Merge branch 'bugfix/init_memctl' into 'master'

bootloader, esp32: add workaround for Tensilica erratum 572

See merge request idf/esp-idf!3605

components/esp32/cpu_start.c

@@ -124,6 +124,7 @@ void IRAM_ATTR call_start_cpu0()
     RESET_REASON rst_reas[2];
 #endif
     cpu_configure_region_protection();
+    cpu_init_memctl();
 
     //Move exception vectors to IRAM
     asm volatile (\
@@ -249,6 +250,7 @@ void IRAM_ATTR call_start_cpu1()
 
     ets_set_appcpu_boot_addr(0);
     cpu_configure_region_protection();
+    cpu_init_memctl();
 
 #if CONFIG_CONSOLE_UART_NONE
     ets_install_putc1(NULL);

components/esp32/include/xtensa/config/core.h

@@ -1401,5 +1401,16 @@ extern const unsigned int  XCJOIN(Xthal_cp_mask_,XCHAL_CP7_IDENT);
 #define XCHAL_ERRATUM_497	0
 #endif
 
+/*
+ * Erratum 572 (releases TBD, but present in ESP32)
+ * Disable zero-overhead loop buffer to prevent rare illegal instruction
+ * exceptions while executing zero-overhead loops.
+ */
+#if ( XCHAL_HAVE_LOOPS && XCHAL_LOOP_BUFFER_SIZE != 0 )
+#define XCHAL_ERRATUM_572   1
+#else
+#define XCHAL_ERRATUM_572   0
+#endif
+
 #endif /*XTENSA_CONFIG_CORE_H*/