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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 11:16:45 +0200
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 11:16:45 +0200
commit96ae6ea0be1b902c28b3b463c27da42b41e2b63a (patch)
treefbc18761d4fa93d7b0f6dbf3496289fa32bd363a /arch/x86/boot/memory.c
parent0530bf37cebcf22a73652937c2340bc1ebd92000 (diff)
downloadlinux-96ae6ea0be1b902c28b3b463c27da42b41e2b63a.tar.gz
i386: move boot
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/boot/memory.c')
-rw-r--r--arch/x86/boot/memory.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
new file mode 100644
index 000000000000..378353956b5d
--- /dev/null
+++ b/arch/x86/boot/memory.c
@@ -0,0 +1,118 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/memory.c
+ *
+ * Memory detection code
+ */
+
+#include "boot.h"
+
+#define SMAP 0x534d4150 /* ASCII "SMAP" */
+
+static int detect_memory_e820(void)
+{
+ int count = 0;
+ u32 next = 0;
+ u32 size, id;
+ u8 err;
+ struct e820entry *desc = boot_params.e820_map;
+
+ do {
+ size = sizeof(struct e820entry);
+
+ /* Important: %edx is clobbered by some BIOSes,
+ so it must be either used for the error output
+ or explicitly marked clobbered. */
+ asm("int $0x15; setc %0"
+ : "=d" (err), "+b" (next), "=a" (id), "+c" (size),
+ "=m" (*desc)
+ : "D" (desc), "d" (SMAP), "a" (0xe820));
+
+ /* Some BIOSes stop returning SMAP in the middle of
+ the search loop. We don't know exactly how the BIOS
+ screwed up the map at that point, we might have a
+ partial map, the full map, or complete garbage, so
+ just return failure. */
+ if (id != SMAP) {
+ count = 0;
+ break;
+ }
+
+ if (err)
+ break;
+
+ count++;
+ desc++;
+ } while (next && count < E820MAX);
+
+ return boot_params.e820_entries = count;
+}
+
+static int detect_memory_e801(void)
+{
+ u16 ax, bx, cx, dx;
+ u8 err;
+
+ bx = cx = dx = 0;
+ ax = 0xe801;
+ asm("stc; int $0x15; setc %0"
+ : "=m" (err), "+a" (ax), "+b" (bx), "+c" (cx), "+d" (dx));
+
+ if (err)
+ return -1;
+
+ /* Do we really need to do this? */
+ if (cx || dx) {
+ ax = cx;
+ bx = dx;
+ }
+
+ if (ax > 15*1024)
+ return -1; /* Bogus! */
+
+ /* This ignores memory above 16MB if we have a memory hole
+ there. If someone actually finds a machine with a memory
+ hole at 16MB and no support for 0E820h they should probably
+ generate a fake e820 map. */
+ boot_params.alt_mem_k = (ax == 15*1024) ? (dx << 6)+ax : ax;
+
+ return 0;
+}
+
+static int detect_memory_88(void)
+{
+ u16 ax;
+ u8 err;
+
+ ax = 0x8800;
+ asm("stc; int $0x15; setc %0" : "=bcdm" (err), "+a" (ax));
+
+ boot_params.screen_info.ext_mem_k = ax;
+
+ return -err;
+}
+
+int detect_memory(void)
+{
+ int err = -1;
+
+ if (detect_memory_e820() > 0)
+ err = 0;
+
+ if (!detect_memory_e801())
+ err = 0;
+
+ if (!detect_memory_88())
+ err = 0;
+
+ return err;
+}