1 files changed, 82 insertions, 0 deletions
diff --git a/sys/arch/amd64/gdt.c b/sys/arch/amd64/gdt.c
new file mode 100644
index 0000000..446306a
--- /dev/null
+++ b/sys/arch/amd64/gdt.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of VegaOS nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* $Id$ */
+
+#include <machine/gdt.h>
+
+struct gdt_entry g_dmmy_gdt[256] = {
+    /* Null */
+    {0},
+
+    /* Kernel code (0x8) */
+    {
+            .limit          = 0x0000,
+            .base_low       = 0x0000,
+            .base_mid       = 0x00,
+            .access         = 0x9A,
+            .granularity    = 0x20,
+            .base_hi        = 0x00
+    },
+
+    /* Kernel data (0x10) */
+    {
+            .limit          = 0x0000,
+            .base_low       = 0x0000,
+            .base_mid       = 0x00,
+            .access         = 0x92,
+            .granularity    = 0x00,
+            .base_hi        = 0x00
+    },
+
+    /* User code (0x18) */
+    {
+            .limit       = 0x0000,
+            .base_low    = 0x0000,
+            .base_mid    = 0x00,
+            .access      = 0xFA,
+            .granularity = 0xAF,
+            .base_hi     = 0x00
+    },
+
+    /* User data (0x20) */
+    {
+            .limit       = 0x0000,
+            .base_low    = 0x0000,
+            .base_mid    = 0x00,
+            .access      = 0xF2,
+            .granularity = 0x00,
+            .base_hi     = 0x00
+    },
+};
+
+struct gdtr g_early_gdtr = {
+    .limit = sizeof(struct gdt_entry) * 256 - 1,
+    .offset = (uintptr_t)&g_dmmy_gdt[0]
+};