CBMEM high table memory manager.

This code adds a very simple toc based memory manager for the high tables area.
The purpose of this code is to make it simpler and more reliable to find
certain data structures in memory. This will also make it possible to have ACPI
S3 Resume working without an ugly hole at 31MB.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Peter Stuge <peter@stuge.se>



git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4860 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
diff --git a/src/arch/i386/boot/gdt.c b/src/arch/i386/boot/gdt.c
new file mode 100644
index 0000000..23250275
--- /dev/null
+++ b/src/arch/i386/boot/gdt.c
@@ -0,0 +1,59 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2008-2009 coresystems GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <types.h>
+#include <string.h>
+#include <cbmem.h>
+#include <console/console.h>
+
+// Global Descriptor Table, defined in c_start.S
+extern char gdt;
+extern char gdt_end;
+
+/* i386 lgdt argument */
+struct gdtarg {
+	u16 limit;
+	u32 base;
+} __attribute__((packed));
+
+// Copy GDT to new location and reload it
+void move_gdt(void)
+{
+	void *newgdt;
+	u16 num_gdt_bytes = &gdt_end - &gdt;
+	struct gdtarg gdtarg;
+
+	newgdt = cbmem_find(CBMEM_ID_GDT);
+	if (!newgdt) {
+		newgdt = cbmem_add(CBMEM_ID_GDT, ALIGN(num_gdt_bytes, 512));
+		if (!newgdt) {
+			printk(BIOS_ERR, "Error: Could not relocate GDT.\n");
+			return;
+		}
+		printk_debug("Moving GDT to %#lx...", newgdt);
+		memcpy((void*)newgdt, &gdt, num_gdt_bytes);
+	}
+
+	gdtarg.base = newgdt;
+	gdtarg.limit = num_gdt_bytes - 1;
+
+	__asm__ __volatile__ ("lgdt %0\n\t" : : "m" (gdtarg));
+	printk_debug("ok\n");
+}
+