1 files changed, 161 insertions, 0 deletions
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
new file mode 100644
index 00000000000..0eeef3989a1
--- /dev/null
+++ b/arch/x86/boot/main.c
@@ -0,0 +1,161 @@
+/* -*- 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/main.c
+ *
+ * Main module for the real-mode kernel code
+ */
+
+#include "boot.h"
+
+struct boot_params boot_params __attribute__((aligned(16)));
+
+char *HEAP = _end;
+char *heap_end = _end;		/* Default end of heap = no heap */
+
+/*
+ * Copy the header into the boot parameter block.  Since this
+ * screws up the old-style command line protocol, adjust by
+ * filling in the new-style command line pointer instead.
+ */
+#define OLD_CL_MAGIC	0xA33F
+#define OLD_CL_ADDRESS	0x20
+
+static void copy_boot_params(void)
+{
+	struct old_cmdline {
+		u16 cl_magic;
+		u16 cl_offset;
+	};
+	const struct old_cmdline * const oldcmd =
+		(const struct old_cmdline *)OLD_CL_ADDRESS;
+
+	BUILD_BUG_ON(sizeof boot_params != 4096);
+	memcpy(&boot_params.hdr, &hdr, sizeof hdr);
+
+	if (!boot_params.hdr.cmd_line_ptr &&
+	    oldcmd->cl_magic == OLD_CL_MAGIC) {
+		/* Old-style command line protocol. */
+		u16 cmdline_seg;
+
+		/* Figure out if the command line falls in the region
+		   of memory that an old kernel would have copied up
+		   to 0x90000... */
+		if (oldcmd->cl_offset < boot_params.hdr.setup_move_size)
+			cmdline_seg = ds();
+		else
+			cmdline_seg = 0x9000;
+
+		boot_params.hdr.cmd_line_ptr =
+			(cmdline_seg << 4) + oldcmd->cl_offset;
+	}
+}
+
+/*
+ * Set the keyboard repeat rate to maximum.  Unclear why this
+ * is done here; this might be possible to kill off as stale code.
+ */
+static void keyboard_set_repeat(void)
+{
+	u16 ax = 0x0305;
+	u16 bx = 0;
+	asm volatile("int $0x16"
+		     : "+a" (ax), "+b" (bx)
+		     : : "ecx", "edx", "esi", "edi");
+}
+
+/*
+ * Get Intel SpeedStep (IST) information.
+ */
+static void query_ist(void)
+{
+	asm("int $0x15"
+	    : "=a" (boot_params.ist_info.signature),
+	      "=b" (boot_params.ist_info.command),
+	      "=c" (boot_params.ist_info.event),
+	      "=d" (boot_params.ist_info.perf_level)
+	    : "a" (0x0000e980),	 /* IST Support */
+	      "d" (0x47534943)); /* Request value */
+}
+
+/*
+ * Tell the BIOS what CPU mode we intend to run in.
+ */
+static void set_bios_mode(void)
+{
+#ifdef CONFIG_X86_64
+	u32 eax, ebx;
+
+	eax = 0xec00;
+	ebx = 2;
+	asm volatile("int $0x15"
+		     : "+a" (eax), "+b" (ebx)
+		     : : "ecx", "edx", "esi", "edi");
+#endif
+}
+
+void main(void)
+{
+	/* First, copy the boot header into the "zeropage" */
+	copy_boot_params();
+
+	/* End of heap check */
+	if (boot_params.hdr.loadflags & CAN_USE_HEAP) {
+		heap_end = (char *)(boot_params.hdr.heap_end_ptr
+				    +0x200-STACK_SIZE);
+	} else {
+		/* Boot protocol 2.00 only, no heap available */
+		puts("WARNING: Ancient bootloader, some functionality "
+		     "may be limited!\n");
+	}
+
+	/* Make sure we have all the proper CPU support */
+	if (validate_cpu()) {
+		puts("Unable to boot - please use a kernel appropriate "
+		     "for your CPU.\n");
+		die();
+	}
+
+	/* Tell the BIOS what CPU mode we intend to run in. */
+	set_bios_mode();
+
+	/* Detect memory layout */
+	detect_memory();
+
+	/* Set keyboard repeat rate (why?) */
+	keyboard_set_repeat();
+
+	/* Set the video mode */
+	set_video();
+
+	/* Query MCA information */
+	query_mca();
+
+	/* Voyager */
+#ifdef CONFIG_X86_VOYAGER
+	query_voyager();
+#endif
+
+	/* Query Intel SpeedStep (IST) information */
+	query_ist();
+
+	/* Query APM information */
+#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
+	query_apm_bios();
+#endif
+
+	/* Query EDD information */
+#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
+	query_edd();
+#endif
+	/* Do the last things and invoke protected mode */
+	go_to_protected_mode();
+}