esp32c3: memprot API upgrade and test application

Closes IDF-2641

tools/test_apps/system/memprot/main/esp32c3/test_panic.c

@@ -0,0 +1,52 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// 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 "riscv/rvruntime-frames.h"
+#include "esp_private/panic_internal.h"
+
+#define MCAUSE_ILLEGAL_INSTRUCTION  2
+
+extern void esp_panic_handler(panic_info_t *info);
+volatile bool g_override_illegal_instruction = false;
+
+void __real_esp_panic_handler(panic_info_t *info);
+
+void return_from_panic_handler(RvExcFrame *frm) __attribute__((noreturn));
+
+/* Memprot test specific IllegalInstruction exception handler:
+ * when testing the protection against a code execution, sample code
+ * is being injected into various memory regions which produces
+ * Illegal instruction on execution attempt. Such a result is expected
+ * but it causes system reboot in the standard panic handler.
+ * The following variant of panic handling simply returns back to the
+ * next instruction and continues normal execution.
+ *
+ * NOTE: if Illegal instruction comes from a different source than the testing code
+ * the behavior is undefined
+ * */
+void __wrap_esp_panic_handler(panic_info_t *info)
+{
+    RvExcFrame *frm = (RvExcFrame *)info->frame;
+    if ( frm->mcause == MCAUSE_ILLEGAL_INSTRUCTION && g_override_illegal_instruction == true ) {
+        /* Return from exception to the return address that called the faulting function.
+        */
+        frm->mepc = frm->ra;
+
+        /* Restore the CPU state and return from the exception.
+        */
+        return_from_panic_handler(frm);
+    } else {
+        __real_esp_panic_handler(info);
+    }
+}