exo: implement start of mariko fatal handler

exosphere/mariko_fatal/source/fatal_crt0_cpp.cpp

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <exosphere.hpp>
+
+extern "C" void __libc_init_array();
+
+namespace ams::secmon::fatal {
+
+    void Initialize(uintptr_t bss_start, size_t bss_end) {
+        /* Clear bss. */
+        std::memset(reinterpret_cast<void *>(bss_start),      0, bss_end - bss_start);
+
+        /* Call init array. */
+        __libc_init_array();
+    }
+
+}