esp32: Port the bootloader patch

currently esp32 protected mode requires a patched bootloader.
it's a bit cumbersome to build the bootloader for that purpose.

this commit attempts to remove the need of the patched bootloader
by applying the changes by ourselves using esp hal.

arch/xtensa/src/esp32/Make.defs

@@ -42,6 +42,9 @@ endif
 
 ifeq ($(CONFIG_BUILD_PROTECTED),y)
 CHIP_CSRCS += esp32_userspace.c
+ifeq ($(CONFIG_ESP32_PID),y)
+CHIP_CSRCS += esp32_userspace_pid.c
+endif
 endif
 
 ifeq ($(CONFIG_SCHED_TICKLESS),y)

arch/xtensa/src/esp32/esp32_userspace.c

@@ -188,6 +188,11 @@ static noinline_function IRAM_ATTR void configure_flash_mmu(void)
                              irom_lma_aligned, 64,
                              (int)irom_page_count) == 0);
 
+#ifdef CONFIG_ESP32_PID
+  extern void esp32_userspace_init_for_pid(void);
+  esp32_userspace_init_for_pid();
+#endif
+
   cache_read_enable(0);
 }
 

arch/xtensa/src/esp32/esp32_userspace_pid.c

@@ -0,0 +1,80 @@
+/****************************************************************************
+ * arch/xtensa/src/esp32/esp32_userspace_pid.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include "esp_attr.h"
+
+#include "hal/mmu_hal.h"
+#include "hal/mmu_ll.h"
+#include "hal/cache_ll.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp32_userspace_init_for_pid
+ *
+ * Description:
+ *   A helper for esp32_userspace.
+ *   Separated to avoid conflicts between esp hal vs nuttx.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+IRAM_ATTR void
+esp32_userspace_init_for_pid(void)
+{
+  int i;
+
+  /* Xtensa CPU does speculative load/store on VAddr1/2/3 when connected
+   * to cache. Hence it requires all the pages of VAddr2/3 to be set valid
+   * to any physical page.
+   * Marking any page invalid would stall the CPU.
+   */
+
+  for (i = 64; i < 256; i++)
+    {
+      if (!mmu_ll_check_entry_valid(0, i))
+        {
+          mmu_ll_write_entry(0, i, 0, MMU_TARGET_FLASH0);
+        }
+
+      if (!mmu_ll_check_entry_valid(1, i))
+        {
+          mmu_ll_write_entry(1, i, 0, MMU_TARGET_FLASH0);
+        }
+    }
+
+  cache_ll_l1_enable_bus(0, CACHE_BUS_IBUS1);
+#ifdef CONFIG_SMP
+  cache_ll_l1_enable_bus(1, CACHE_BUS_IBUS1);
+#endif
+}