Multiboot support (contributed by Feiran "Fam" Zheng);

keep in mind that GRUB needs to be patched to read MFS for now; use /boot/image_latest to boot the last compiled image in GRUB
2010-07-23 14:24:34 +00:00 · 2010-07-23 14:24:34 +00:00 · df0ba02a38
commit df0ba02a38
parent 9212eab21f
13 changed files with 904 additions and 8 deletions
--- a/kernel/arch/i386/Makefile.inc
+++ b/kernel/arch/i386/Makefile.inc
@ -1,3 +1,4 @@
+
 # Makefile for arch-dependent kernel code
 .include <bsd.own.mk>

@ -20,10 +21,19 @@ SRCS+=	arch_do_vmctl.c \
 	io_outl.S \
 	io_outw.S \
 	klib.S \
+	klib16.S \
+	multiboot.S \
 	memory.c \
 	oxpcie.c \
 	protect.c \
 	arch_system.c \
 	apic.c \
 	apic_asm.S \
-	arch_watchdog.c
+	arch_watchdog.c \
+	pre_init.c
+
+I86CPPFLAGS =	-mi86
+I86LDFLAGS =	-mi86
+
+CPPFLAGS.klib16.S =	${I86CPPFLAGS}
+LDFLAGS.klib16.S  =	${I86LDFLAGS}
--- a/kernel/arch/i386/arch_system.c
+++ b/kernel/arch/i386/arch_system.c
@ -22,6 +22,7 @@
 #include "oxpcie.h"
 #include "kernel/proc.h"
 #include "kernel/debug.h"
+#include "multiboot.h"

 #ifdef CONFIG_APIC
 #include "apic.h"
@ -29,6 +30,9 @@

 PRIVATE int osfxsr_feature; /* FXSAVE/FXRSTOR instructions support (SSEx) */

+extern void poweroff_jmp();
+extern void poweroff16();
+extern void poweroff16_end();

 /* set MP and NE flags to handle FPU exceptions in native mode. */
 #define CR0_MP_NE	0x0022
@ -44,6 +48,22 @@ PUBLIC __dead void arch_monitor(void)
 	monitor();
 }

+PUBLIC void arch_bios_poweroff(void)
+{
+	u32_t cr0;
+	
+	/* Disable paging */
+	cr0 = read_cr0();
+	cr0 &= ~I386_CR0_PG;
+	write_cr0(cr0);
+	/* Copy 16-bit poweroff code to below 1M */
+	phys_copy(
+		FUNC2PHY(&poweroff16),
+		BIOS_POWEROFF_ENTRY,
+		(u32_t)&poweroff16_end-(u32_t)&poweroff16);
+	poweroff_jmp();
+}
+
 PUBLIC int cpu_has_tsc;

 PUBLIC __dead void arch_shutdown(const int how)
@ -107,7 +127,10 @@ PUBLIC __dead void arch_shutdown(const int how)

 			arch_set_params(mybuffer, strlen(mybuffer)+1);
 		}
-		arch_monitor();
+		if(mon_return)
+			arch_monitor();
+		else
+			arch_bios_poweroff();
 	} else {
 		/* Reset the system by forcing a processor shutdown. First stop
 		 * the BIOS memory test by setting a soft reset flag.
--- a/kernel/arch/i386/include/archconst.h
+++ b/kernel/arch/i386/include/archconst.h
@ -153,4 +153,7 @@
 /* fpu context should be saved in 16-byte aligned memory */
 #define FPUALIGN		16

+/* Poweroff 16-bit code address */
+#define BIOS_POWEROFF_ENTRY 0x1000
+
 #endif /* _I386_ACONST_H */
--- a/kernel/arch/i386/klib.S
+++ b/kernel/arch/i386/klib.S
@ -4,9 +4,11 @@
 #include <minix/config.h>
 #include <minix/const.h>
 #include <machine/interrupt.h>
+#include <i386/vm.h>
 #include "archconst.h"
 #include "kernel/const.h"
 #include "sconst.h"
+#include "multiboot.h"

 /*
 * This file contains a number of assembly code utility routines needed by the
@ -908,3 +910,54 @@ _switch_address_space:
 0:
 	ret

+/*===========================================================================*/
+/*				poweroff					     */
+/*===========================================================================*/
+/* PUBLIC void poweroff(); */
+/* Jump to 16-bit poweroff code */
+.globl _poweroff_jmp
+_poweroff_jmp:
+	cli
+	/* Make real mode descriptor */
+	mov	$(_gdt + SS_SELECTOR), %edi
+	mov	$0x100, %eax
+	movw %ax, 2(%edi)
+	shr	$16, %eax
+	movb	%al, 4(%edi)
+	and	$0xff00, %ax
+	andw	$0xff, 6(%edi)
+	or	%ax, 6(%edi)
+	mov	$0xffff, %eax
+	movw	%ax, (%edi)
+	shr	$16, %eax
+	and	$0xf, %ax
+	andb	$0xf0, 6(%edi)
+	or	%ax, 6(%edi)
+	
+	/* Flush TLB */
+	xor	%eax, %eax
+	mov	%eax, %cr3
+	
+	xor	%esp, %esp /* clear esp for real mode*/
+	
+	/* Reset IDTR */
+	lidt	idt_ptr
+	
+	mov	$SS_SELECTOR, %ax
+	mov	%ax, %ds
+	mov	%ax, %es
+	mov	%ax, %fs
+	mov	%ax, %gs
+	mov	%ax, %ss
+	
+	/* Save real mode cr0 in eax */
+	mov	%cr0, %eax
+	andl	$~I386_CR0_PE, %eax
+	
+	/* Jump to 16-bit code that is copied to below 1MB */
+	ljmp	$MON_CS_SELECTOR, $0
+	
+.data
+idt_ptr:
+	.short 0x3ff
+	.long 0x0
--- a/kernel/arch/i386/klib16.S
+++ b/kernel/arch/i386/klib16.S
@ -0,0 +1,78 @@
+/* sections */
+
+
+#include <minix/config.h>
+#include <minix/const.h>
+#include <machine/interrupt.h>
+#include "archconst.h"
+#include "kernel/const.h"
+#include "sconst.h"
+#include "multiboot.h"
+
+/*
+ * This file contains a number of 16-bit assembly code utility routines needed by the
+ * kernel.  They are:
+ */
+
+.globl	_poweroff16 /* enter real mode */
+.globl	_poweroff16_end
+
+.text
+
+/*===========================================================================*/
+/*				poweroff16					     */
+/*===========================================================================*/
+/* PUBLIC void poweroff16(); */
+/* Power down system */
+_poweroff16:
+	/* Assume eax is already set to required value of cr0*/
+.byte	0x0F,0x22,0xC0	/* mov %cr0,%eax */
+	jmpf	$0,$(BIOS_POWEROFF_ENTRY + real_mode - _poweroff16)
+real_mode:
+	mov	$((BIOS_POWEROFF_ENTRY >> 4) + 0x200),%ax
+	mov	%ax, %ds
+	mov	%ax, %es
+	mov	%ax, %ss
+	mov	$0x1000, %sp
+
+	xorb	%ah, %ah
+/* Close gate A20 */
+gate_A20:
+	call	kb_wait
+	movb	$0xD1,%al
+	outb	0x64
+	call	kb_wait
+	movb	$0xDD,%al
+	orb		%ah,%al
+	outb	0x60
+	call	kb_wait
+	movb	$0xFF,%al
+	outb	0x64
+	call	kb_wait
+	
+	/* Connect to APM */
+	mov	$0x5301,%ax
+	mov	$0x0,%bx
+	int	0x15
+	
+	/* Enable power management */
+	mov	$0x5308,%ax
+	mov	$0x1,%bx
+	mov	$0x1,%cx
+	int	0x15
+	
+	/* Set power state to off */
+	mov	$0x5307,%ax
+	mov	$0x01,%bx
+	mov	$0x3,%cx
+	int	0x15
+0:	hlt
+	jmp	0b
+	
+kb_wait:
+	inb	0x64
+	testb	$0x02,%al
+	jnz	kb_wait
+	ret
+/*mark the end for copy*/
+_poweroff16_end:
--- a/kernel/arch/i386/mpx.S
+++ b/kernel/arch/i386/mpx.S
@ -6,7 +6,7 @@
 * good environment for main(). 
 *
 * Kernel is entered either because of kernel-calls, ipc-calls, interrupts or
- * exceptions. TSS is set so that the kernel stack is loaded. The user cotext is
+ * exceptions. TSS is set so that the kernel stack is loaded. The user context is
 * saved to the proc table and the handler of the event is called. Once the
 * handler is done, switch_to_user() function is called to pick a new process,
 * finish what needs to be done for the next process to run, sets its context
@ -52,6 +52,7 @@ begbss:
 #include "kernel/const.h"
 #include "kernel/proc.h"
 #include "sconst.h"
+#include "multiboot.h"

 /* Selected 386 tss offsets. */
 #define TSS3_S_SP0	4
@ -133,11 +134,44 @@ flags:
 */
 .short	0x03FD	
 	nop	/* extra byte to sync up disassembler */
-over_flags:
 	
+/* Multiboot header here*/
+
+.balign 8
+
+multiboot_magic:
+	.long MULTIBOOT_HEADER_MAGIC
+multiboot_flags:
+	.long MULTIBOOT_FLAGS
+multiboot_checksum:
+	.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_FLAGS)
+multiboot_header_addr:
+	.long (MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET + multiboot_magic)
+multiboot_load_addr:
+	.long MULTIBOOT_LOAD_ADDRESS
+multiboot_load_end_addr:
+	.long 0
+multiboot_bss_end_addr:
+	.long 0
+multiboot_entry_addr:
+	.long (MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET + multiboot_init)
+/* Video mode */
+multiboot_mode_type:
+	.long MULTIBOOT_VIDEO_MODE_EGA
+multiboot_width:
+	.long MULTIBOOT_CONSOLE_COLS
+multiboot_height:
+	.long MULTIBOOT_CONSOLE_LINES
+multiboot_depth:
+	.long 0
+
+over_flags:
 /* Set up a C stack frame on the monitor stack.  (The monitor sets cs and ds */
 /* right.  The ss descriptor still references the monitor data segment.) */
 	movzwl	%sp, %esp	/* monitor stack is a 16 bit stack */
+
+.globl kernel_init
+kernel_init: /* after pre-init*/
 	push	%ebp
 	mov	%esp, %ebp
 	push	%esi
@ -658,7 +692,6 @@ _reload_cr3:
 .data
 #endif
 .short	0x526F	/* this must be the first data entry (magic #) */
-
 .bss
 /*
 * the kernel stack
--- a/kernel/arch/i386/multiboot.S
+++ b/kernel/arch/i386/multiboot.S
@ -0,0 +1,117 @@
+#include "kernel/kernel.h" /* configures the kernel */
+#include <minix/config.h>
+#include <minix/const.h>
+#include <minix/com.h>
+#include <machine/interrupt.h>
+#include "archconst.h"
+#include "kernel/const.h"
+#include "kernel/proc.h"
+#include "sconst.h"
+#include "multiboot.h"
+
+#define GDT_SET_ENTRY(selector, base, limit) \
+	mov	%ebp, %edi; \
+	add	$(_gdt + selector), %edi; \
+	mov	base, %eax; \
+	movw %ax, 2(%edi); \
+	shr	$16, %eax; \
+	movb	%al, 4(%edi); \
+	and	$0xff00, %ax; \
+	andw	$0xff, 6(%edi); \
+	or	%ax, 6(%edi); \
+	mov	limit, %eax; \
+	movw	%ax, (%edi); \
+	shr	$16, %eax; \
+	and	$0xf, %ax; \
+	andb	$0xf0, 6(%edi); \
+	or	%ax, 6(%edi); \
+	
+.globl _pre_init
+.globl multiboot_init
+.globl kernel_init
+
+multiboot_init:
+	/* Get size of kernel text */
+	mov	MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_text, %ecx
+	
+	/* Get size of kernel text and ceil to 0x1000, and it's the offset
+	   of data seg */
+	mov	%ecx, %eax
+	dec	%eax
+	and	$0xfffff000, %eax
+	add	$0x1000, %eax
+
+	/* Calculate and save kernel data base address */
+	mov	$(MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET), %ebp
+	add	%eax, %ebp
+	mov	%ebp, _kernel_data_addr(%ebp)
+	
+	/* Init text seg */
+	GDT_SET_ENTRY(CS_SELECTOR, \
+				$(MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET), \
+				%ecx)
+	
+	/* Init data seg */
+	GDT_SET_ENTRY(DS_SELECTOR, \
+				%ebp, \
+				MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_total)
+	
+	/* Make up monitor data seg, the same value as DS, different entry */
+	GDT_SET_ENTRY(SS_SELECTOR, \
+				%ebp, \
+				MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_total)
+	
+	/* Make up monitor text seg, used to return to real mode when poweroff */
+	GDT_SET_ENTRY(MON_CS_SELECTOR, \
+				$BIOS_POWEROFF_ENTRY, \
+				$0xffff)
+	
+	mov	$(GDT_SIZE*DESC_SIZE), %eax
+	mov	%ebp, %edi
+	add	$(_gdt + GDT_SELECTOR), %edi
+	mov	%ax, (%edi)
+	mov	%ebp, %eax
+	add	$_gdt, %eax
+	mov	%eax, 2(%edi)
+	lgdt	(%edi)
+	
+	ljmp	$(CS_SELECTOR), $reload_cs
+	
+reload_cs:
+	mov	$DS_SELECTOR, %eax
+	mov	%eax, %ds
+	mov	%eax, %ss
+	mov	%eax, %es
+	
+	mov	$(multiboot_stack + MULTIBOOT_STACK_SIZE), %esp
+
+	push	%ebx
+	call	_pre_init
+	
+	add	$4, %esp
+	
+	/* return to old boot code of kernel */
+	push	%eax
+	push	$MULTIBOOT_PARAM_BUF_SIZE
+	push	$_multiboot_param_buf
+	push	$0
+	
+	mov	$ES_SELECTOR, %eax
+	mov	%eax, %es
+	
+	jmp	kernel_init
+
+.data
+.globl _kernel_data_addr
+_kernel_data_addr:
+.long	0
+.globl _a_out_headers
+_a_out_headers:
+.space	NR_BOOT_PROCS * 32 /* is A_MINHDR */
+
+.globl _multiboot_param_buf
+_multiboot_param_buf:
+.space	MULTIBOOT_PARAM_BUF_SIZE
+
+multiboot_stack:
+.space	MULTIBOOT_STACK_SIZE + 4
--- a/kernel/arch/i386/multiboot.h
+++ b/kernel/arch/i386/multiboot.h
@ -0,0 +1,136 @@
+#ifndef __MULTIBOOT_H__
+#define __MULTIBOOT_H__
+
+#define MULTIBOOT_HEADER_MAGIC 0x1BADB002
+
+#define MULTIBOOT_BOOTLOADER_MAGIC 0x2BADB002
+
+/* Must pass memory information to OS. */
+#define MULTIBOOT_MEMORY_INFO 0x00000002
+
+#define MULTIBOOT_VIDEO_MODE 0x00000004
+
+#define MULTIBOOT_AOUT_KLUDGE 0x00010000
+
+#define MULTIBOOT_FLAGS (MULTIBOOT_MEMORY_INFO | \
+						MULTIBOOT_VIDEO_MODE | \
+						MULTIBOOT_AOUT_KLUDGE)
+						
+/* consts used for Multiboot pre-init */
+
+#define MULTIBOOT_ENTRY_OFFSET 0x200
+
+#define MULTIBOOT_LOAD_ADDRESS 0x200000-MULTIBOOT_ENTRY_OFFSET
+
+#define MULTIBOOT_VIDEO_MODE_EGA 1
+
+#define MULTIBOOT_VIDEO_BUFFER 0xB8000
+
+/* Usable lower memory chunk has a upper bound */
+#define MULTIBOOT_LOWER_MEM_MAX 0x7f800
+
+#define MULTIBOOT_CONSOLE_LINES 25
+#define MULTIBOOT_CONSOLE_COLS 80
+
+
+#define MULTIBOOT_STACK_SIZE 4096
+#define MULTIBOOT_PARAM_BUF_SIZE 1024
+
+#define MULTIBOOT_KERNEL_a_text 0x48
+#define MULTIBOOT_KERNEL_a_data (0x48+4)
+#define MULTIBOOT_KERNEL_a_total (0x48+16)
+
+/* Flags to be set in the ’flags’ member of the multiboot info structure. */
+
+#define MULTIBOOT_INFO_MEMORY 0x00000001
+
+/* Is there a boot device set? */
+#define MULTIBOOT_INFO_BOOTDEV 0x00000002
+
+/* Is the command-line defined? */
+#define MULTIBOOT_INFO_CMDLINE 0x00000004
+
+/* Are there modules to do something with? */
+#define MULTIBOOT_INFO_MODS 0x00000008
+
+/* get physical address by data pointer*/
+#define PTR2PHY(ptr) (kernel_data_addr+(u32_t)(ptr))
+
+/* get data pointer by physical address*/
+#define PHY2PTR(phy) ((char *)((u32_t)(phy)-kernel_data_addr))
+
+/* Get physical address by function pointer*/
+#define FUNC2PHY(fun) (MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET + (u32_t)(fun))
+
+#ifndef __ASSEMBLY__
+
+#include <minix/types.h>
+/* The symbol table for a.out. */
+struct multiboot_aout_symbol_table
+{
+	u32_t tabsize;
+	u32_t strsize;
+	u32_t addr;
+	u32_t reserved;
+};
+/* The section header table for ELF. */
+struct multiboot_elf_section_header_table
+{
+	u32_t num;
+	u32_t size;
+	u32_t addr;
+	u32_t shndx;
+};
+
+typedef struct multiboot_elf_section_header_table multiboot_elf_section_header_table_t;
+typedef struct multiboot_aout_symbol_table multiboot_aout_symbol_table_t;
+
+struct multiboot_info
+{
+	/* Multiboot info version number */
+	u32_t flags;
+	/* Available memory from BIOS */
+	u32_t mem_lower;
+	u32_t mem_upper;
+	/* "root" partition */
+	u32_t boot_device;
+	/* Kernel command line */
+	u32_t cmdline;
+	/* Boot-Module list */
+	u32_t mods_count;
+	u32_t mods_addr;
+	union
+	{
+		multiboot_aout_symbol_table_t aout_sym;
+		multiboot_elf_section_header_table_t elf_sec;
+	} u;
+	/* Memory Mapping buffer */
+	u32_t mmap_length;
+	u32_t mmap_addr;
+	/* Drive Info buffer */
+	u32_t drives_length;
+	u32_t drives_addr;
+	/* ROM configuration table */
+	u32_t config_table;
+	/* Boot Loader Name */
+	u32_t boot_loader_name;
+	/* APM table */
+	u32_t apm_table;
+	/* Video */
+	u32_t vbe_control_info;
+	u32_t vbe_mode_info;
+	u16_t vbe_mode;
+	u16_t vbe_interface_seg;
+	u16_t vbe_interface_off;
+	u16_t vbe_interface_len;
+};
+typedef struct multiboot_info multiboot_info_t;
+
+/* Buffer for multiboot parameters */
+extern char multiboot_param_buf[];
+
+/* Physical address of kernel data segment */
+extern phys_bytes kernel_data_addr;
+
+#endif /* __ASSEMBLY__ */
+#endif /* __MULTIBOOT_H__ */
--- a/kernel/arch/i386/pre_init.c
+++ b/kernel/arch/i386/pre_init.c
@ -0,0 +1,415 @@
+#include "kernel/kernel.h"
+#include <minix/minlib.h>
+#include <minix/const.h>
+/*
+ * == IMPORTANT == 
+ * Routines in this file can not use any variable in kernel BSS, 
+ * since before image is extracted, no BSS is allocated. 
+ * So pay attention to any external call (including library call).
+ * 
+ * */
+#include <minix/types.h>
+#include <minix/type.h>
+#include <minix/com.h>
+#include <minix/a.out.h>
+#include <machine/partition.h>
+#include "../../../boot/image.h"
+#include "string.h"
+#include "proto.h"
+#include "multiboot.h"
+
+/* Granularity used in image file and copying */
+#define GRAN 512
+#define SECT_CEIL(x) ((((x) - 1) / GRAN + 1) * GRAN)
+
+/* String length used for mb_itoa */
+#define ITOA_BUFFER_SIZE 20
+
+/* The a.out headers to pass to kernel. 
+ * Not using struct exec because only using short form */
+extern char a_out_headers[];
+
+#define mb_load_phymem(buf, phy, len) \
+		phys_copy((phy), PTR2PHY(buf), (len))
+
+#define mb_save_phymem(buf, phy, len) \
+		phys_copy(PTR2PHY(buf), (phy), (len))
+
+PRIVATE void mb_phys_move(u32_t src, u32_t dest, u32_t len) 
+{
+	char data[GRAN + 1];
+	int i;
+	/* Move upward (start moving from tail), block by block 
+	* len should be aligned to GRAN 
+	*/
+	if (len % GRAN) {
+		mb_print("fatal: not aligned phys move");
+		/* Spin here */
+		while (1)
+			;
+	}
+
+	len /= GRAN;
+	for (i = len - 1; i >= 0; i--) {
+		mb_load_phymem(data, src + i * GRAN, GRAN);
+		mb_save_phymem(data, dest + i * GRAN, GRAN);
+	}
+}
+
+PRIVATE void mb_itoa(u32_t val, char * out) 
+{
+	char ret[ITOA_BUFFER_SIZE];
+	int i = ITOA_BUFFER_SIZE - 2;
+	/* Although there's a library version of itoa(int n), 
+	* we can't use it since that implementation relies on BSS segment
+	*/
+	ret[ITOA_BUFFER_SIZE - 2] = '0';
+	if (val) {
+		for (; i >= 0; i--) {
+			char c;
+			if (val == 0) break;
+			c = val % 10;
+			val = val / 10;
+				c += '0';
+			ret[i] = c;
+		}
+	}
+	else
+		i--;
+	ret[ITOA_BUFFER_SIZE - 1] = 0;
+	strcpy(out, ret + i + 1);
+}
+
+PRIVATE void mb_itox(u32_t val, char *out) 
+{
+	char ret[9];
+	int i = 7;
+	/* Convert a number to hex string */
+	ret[7] = '0';
+	if (val) {
+		for (; i >= 0; i--) {
+			char c;
+			if (val == 0) break;
+			c = val & 0xF;
+			val = val >> 4;
+			if (c > 9)
+				c += 'A' - 10;
+			else
+				c += '0';
+			ret[i] = c;
+		}	
+	}
+	else
+		i--;
+	ret[8] = 0;
+	strcpy(out, ret + i + 1);
+}
+
+PRIVATE void mb_put_char(char c, int line, int col) 
+{
+	/* Write a char to vga display buffer. */
+	if (line<MULTIBOOT_CONSOLE_LINES&&col<MULTIBOOT_CONSOLE_COLS)
+		mb_save_phymem(
+			&c, 
+			MULTIBOOT_VIDEO_BUFFER 
+				+ line * MULTIBOOT_CONSOLE_COLS * 2 
+				+ col * 2, 
+			1);
+}
+
+PRIVATE char mb_get_char(int line, int col) 
+{
+	char c;
+	/* Read a char to from display buffer. */
+	if (line < MULTIBOOT_CONSOLE_LINES && col < MULTIBOOT_CONSOLE_COLS)
+		mb_load_phymem(
+			&c, 
+			MULTIBOOT_VIDEO_BUFFER 
+			+ line * MULTIBOOT_CONSOLE_COLS * 2 
+			+ col * 2, 
+			1);
+	return c;
+}
+
+/* Give non-zero values to avoid them in BSS */
+PRIVATE int print_line = 1, print_col = 1;
+	
+PRIVATE void mb_cls(void) 
+{
+	int i, j;
+	/* Clear screen */
+	for (i = 0; i < MULTIBOOT_CONSOLE_LINES; i++ )
+		for (j = 0; j < MULTIBOOT_CONSOLE_COLS; j++ )
+			mb_put_char(0, i, j);
+	print_line = print_col = 0;
+}
+
+PRIVATE void mb_scroll_up(int lines) 
+{
+	int i, j;
+	for (i = 0; i < MULTIBOOT_CONSOLE_LINES - lines; i++ ) {
+		for (j = 0; j < MULTIBOOT_CONSOLE_COLS; j++ )
+			mb_put_char(mb_get_char(i + lines, j), i, j);
+	}
+	print_line-= lines;
+}
+
+PRIVATE void mb_print(char *str) 
+{
+	while (*str) {
+		if (*str == '\n') {
+			str++;
+			print_line++;
+			print_col = 0;
+			continue;
+		}
+		mb_put_char(*str++, print_line, print_col++);
+		if (print_col >= MULTIBOOT_CONSOLE_COLS) {
+			print_line++;
+			print_col = 0;
+		}
+		while (print_line >= MULTIBOOT_CONSOLE_LINES)
+			mb_scroll_up(1);
+	}
+}
+
+PRIVATE void mb_print_hex(u32_t value) 
+{
+	int i;
+	char c;
+	char out[9] = "00000000";
+	/* Print a hex value */
+	for (i = 7; i >= 0; i--) {
+		c = value % 0x10;
+		value /= 0x10;
+		if (c < 10) 
+			c += '0';
+		else
+			c += 'A'-10;
+		out[i] = c;
+	}
+	mb_print(out);
+}
+
+PRIVATE int mb_set_param(char *name, char *value) 
+{
+	char *p = multiboot_param_buf;
+	char *q;
+	int namelen = strlen(name);
+	int valuelen = strlen(value);
+	
+	/* Delete the item if already exists */
+	while (*p) {
+		if (strncmp(p, name, namelen) == 0 && p[namelen] == '=') {
+			q = p;
+			while (*q) q++;
+			for (q++; 
+				q < multiboot_param_buf + MULTIBOOT_PARAM_BUF_SIZE; 
+				q++, p++)
+				*p = *q;
+			break;
+		}
+		while (*p++)
+			;
+		p++;
+	}
+	
+	for (p = multiboot_param_buf;
+		p < multiboot_param_buf + MULTIBOOT_PARAM_BUF_SIZE 
+			&& (*p || *(p + 1));
+		p++)
+		;
+	if (p > multiboot_param_buf) p++;
+	
+	/* Make sure there's enough space for the new parameter */
+	if (p + namelen + valuelen + 3 
+		> multiboot_param_buf + MULTIBOOT_PARAM_BUF_SIZE)
+		return -1;
+	
+	strcpy(p, name);
+	p[namelen] = '=';
+	strcpy(p + namelen + 1, value);
+	p[namelen + valuelen + 1] = 0;
+	p[namelen + valuelen + 2] = 0;
+	return 0;
+}
+
+PRIVATE void get_parameters(multiboot_info_t *mbi) 
+{
+	char mem_value[40], temp[ITOA_BUFFER_SIZE];
+	int i, r, processor;
+	int dev;
+	int ctrlr;
+	int disk, prim, sub;
+	int var_i,value_i;
+	char *p;
+	const static int dev_cNd0[] = { 0x0300, 0x0800, 0x0A00, 0x0C00, 0x1000 };
+	static char mb_cmd_buff[GRAN] = "add some value to avoid me in BSS";
+	static char var[GRAN] = "add some value to avoid me in BSS";
+	static char value[GRAN] = "add some value to avoid me in BSS";
+	for (i = 0; i < MULTIBOOT_PARAM_BUF_SIZE; i++)
+		multiboot_param_buf[i] = 0;
+	
+	if (mbi->flags & MULTIBOOT_INFO_BOOTDEV) {
+		sub = 0xff;
+		disk = ((mbi->boot_device&0xff000000) >> 24)-0x80;
+		prim = (mbi->boot_device&0xff0000) == 0xff0000 ? 
+			0 : (mbi->boot_device & 0xff0000) >> 16;
+		ctrlr = 0;
+		dev = dev_cNd0[ctrlr];
+		/* Determine the value of rootdev */
+		if ((mbi->boot_device & 0xff00) == 0xff00) {
+			dev += disk * (NR_PARTITIONS + 1) + (prim + 1);
+		} else {
+			sub = (mbi->boot_device & 0xff00) >> 8;
+			dev += 0x80
+				 + (disk * NR_PARTITIONS + prim) * NR_PARTITIONS 
+				 + sub;
+		}
+		mb_itoa(dev, temp);
+		mb_set_param("rootdev", temp);
+		mb_set_param("ramimagedev", temp);
+	}
+	mb_set_param("ramsize", "0");
+	mb_set_param("hz", "60");
+	processor = getprocessor();
+	if (processor == 1586) processor = 686;
+	mb_itoa(processor, temp);
+	mb_set_param("processor", temp);
+	mb_set_param("bus", "at");
+	mb_set_param("video", "ega");
+	mb_set_param("chrome", "color");
+	
+	if (mbi->flags & MULTIBOOT_INFO_MEMORY)
+	{
+		strcpy(mem_value, "800:");
+		mb_itox(
+			mbi->mem_lower * 1024 > MULTIBOOT_LOWER_MEM_MAX ? 
+				MULTIBOOT_LOWER_MEM_MAX : mbi->mem_lower * 1024, 
+			temp);
+		strcat(mem_value, temp);
+		strcat(mem_value, ",100000:");
+		mb_itox(mbi->mem_upper * 1024, temp);
+		strcat(mem_value, temp);
+		mb_set_param("memory", mem_value);
+	}
+	
+	/* FIXME: this is dummy value, 
+	 * we can't get real image file name from multiboot */
+	mb_set_param("image", "boot/image_latest");
+	
+	if (mbi->flags&MULTIBOOT_INFO_CMDLINE) {
+		/* Override values with cmdline argument */
+		p = mb_cmd_buff;
+		mb_load_phymem(mb_cmd_buff, mbi->cmdline, GRAN);
+		while (*p) {
+			var_i = 0;
+			value_i = 0;
+			while (*p == ' ') p++;
+			if (!*p) break;
+			while (*p && *p != '=' && var_i < GRAN - 1) 
+				var[var_i++] = *p++ ;
+			var[var_i] = 0;
+			p++; /* skip '=' */
+			while (*p && *p != ' ' && value_i < GRAN - 1) 
+				value[value_i++] = *p++ ;
+			value[value_i] = 0;
+			
+			mb_set_param(var, value);
+		}
+	}
+}
+
+PRIVATE void mb_extract_image(void)
+{
+	int i;
+	u32_t text_addr[NR_BOOT_PROCS];
+	u32_t imghdr_addr = MULTIBOOT_LOAD_ADDRESS;
+	int off_sum = 0;
+	struct exec *aout_hdr;
+	int empty, clear_size, j;
+	u32_t p;
+	/* Extract the image to align segments and clear up BSS 
+	 */
+	for (i = 0; i < LAST_SPECIAL_PROC_NR + 2; i++) {
+		aout_hdr = (struct exec *) (a_out_headers + A_MINHDR * i);
+		mb_load_phymem(aout_hdr, imghdr_addr + IM_NAME_MAX + 1, A_MINHDR);
+		text_addr[i] = imghdr_addr + GRAN;
+		if (aout_hdr->a_flags & A_SEP) {
+			off_sum += CLICK_CEIL(aout_hdr->a_total)
+					- SECT_CEIL(aout_hdr->a_data)
+					+ CLICK_CEIL(aout_hdr->a_text)
+					- SECT_CEIL(aout_hdr->a_text)
+					- GRAN;
+			imghdr_addr += SECT_CEIL(aout_hdr->a_text)
+					+ SECT_CEIL(aout_hdr->a_data)
+					+ GRAN;
+		} else {
+			off_sum += CLICK_CEIL(aout_hdr->a_total) 
+					- SECT_CEIL(aout_hdr->a_data + aout_hdr->a_text)
+					- GRAN;
+			imghdr_addr += SECT_CEIL(aout_hdr->a_text + aout_hdr->a_data)
+					+ GRAN;
+		}
+	}
+	for (i = LAST_SPECIAL_PROC_NR + 1; i >= 0;i--) {
+		struct exec * aout_hdr = (struct exec *) (a_out_headers + A_MINHDR * i);
+		if (aout_hdr->a_flags & A_SEP)
+			off_sum -= CLICK_CEIL(aout_hdr->a_total) 
+					- SECT_CEIL(aout_hdr->a_data)
+					+ CLICK_CEIL(aout_hdr->a_text)
+					- SECT_CEIL(aout_hdr->a_text)
+					- GRAN;
+		else
+			off_sum -= CLICK_CEIL(aout_hdr->a_total) 
+					- SECT_CEIL(aout_hdr->a_data + aout_hdr->a_text)
+					- GRAN;
+		if (i > 0) { /* if not kernel */
+			if (aout_hdr->a_flags & A_SEP)	{
+				mb_phys_move(text_addr[i], text_addr[i] + off_sum, 
+					SECT_CEIL(aout_hdr->a_text));
+				mb_phys_move(text_addr[i] + SECT_CEIL(aout_hdr->a_text), 
+					text_addr[i] + off_sum + CLICK_CEIL(aout_hdr->a_text), 
+					SECT_CEIL(aout_hdr->a_data));
+			} else {
+				mb_phys_move(text_addr[i], text_addr[i] + off_sum, 
+					SECT_CEIL(aout_hdr->a_text + aout_hdr->a_data));
+			}
+		}
+		aout_hdr->a_syms = text_addr[i] + off_sum;
+		
+		/* Clear out for expanded text, BSS and stack */
+		empty = 0;
+		if (aout_hdr->a_flags & A_SEP) {
+			p = text_addr[i] + off_sum
+				+ CLICK_CEIL(aout_hdr->a_text) 
+				+ aout_hdr->a_data;
+			clear_size = CLICK_CEIL(aout_hdr->a_total) - aout_hdr->a_data;
+		} else {
+			p = text_addr[i] + off_sum
+				+ aout_hdr->a_text
+				+ aout_hdr->a_data;
+			clear_size = CLICK_CEIL(aout_hdr->a_total) 
+				- aout_hdr->a_data
+				- aout_hdr->a_text;
+		}
+		/* FIXME: use faster function */
+		for (j = 0; j < clear_size; j++)
+			mb_save_phymem(&empty, p + j, 1);
+	}
+}
+
+PUBLIC u32_t pre_init(u32_t ebx)
+{
+	multiboot_info_t mbi;
+	/* Do pre-initialization for multiboot, returning physical address of
+	* a_out_headers 
+	*/
+	mb_cls();
+	mb_print("\nMINIX booting... ");
+	mb_load_phymem(&mbi, ebx, sizeof(mbi));
+	get_parameters(&mbi);
+	mb_print("\nLoading image... ");
+	mb_extract_image();
+	return PTR2PHY(a_out_headers);
+}
--- a/kernel/arch/i386/protect.c
+++ b/kernel/arch/i386/protect.c
@ -25,7 +25,16 @@ struct gatedesc_s {
  u16_t offset_high;
 };

-PUBLIC struct segdesc_s gdt[GDT_SIZE];		/* used in klib.s and mpx.s */
+PUBLIC struct segdesc_s gdt[GDT_SIZE]=		/* used in klib.s and mpx.s */
+{	{0},
+	{0,0,0,0}, 				/* GDT descriptor */
+	{0,0,0,0}, 				/* IDT descriptor */
+	{0xffff,0,0,0x92,0x4f,0}, 	/* kernel DS */
+	{0xffff,0,0,0x92,0xcf,0},	/* kernel ES (386: flag 4 Gb at startup) */
+	{0xffff,0,0,0x92,0x4f,0},	/* kernel SS (386: monitor SS at startup) */
+	{0xffff,0,0,0x9a,0x4f,0},	/* kernel CS */
+	{0xffff,0,0,0x9a,0x0f,0},	/* temp for BIOS (386: monitor CS at startup) */
+};
 PRIVATE struct gatedesc_s idt[IDT_SIZE];	/* zero-init so none present */
 PUBLIC struct tss_s tss;			/* zero init */

--- a/kernel/proto.h
+++ b/kernel/proto.h
@ -171,6 +171,7 @@ _PROTOTYPE( void arch_init, (void)                                     );
 _PROTOTYPE( void ser_putc, (char)						);
 _PROTOTYPE( __dead void arch_shutdown, (int)				);
 _PROTOTYPE( __dead void arch_monitor, (void)				);
+_PROTOTYPE( void arch_bios_poweroff, (void)					);
 _PROTOTYPE( void arch_get_aout_headers, (int i, struct exec *h)		);
 _PROTOTYPE( void restore_user_context, (struct proc * p)                );
 _PROTOTYPE( void read_tsc, (unsigned long *high, unsigned long *low)    );
--- a/tools/Makefile
+++ b/tools/Makefile
@ -4,7 +4,7 @@ u=/usr
 MDEC=	/usr/mdec

 # Specify the programs that are part of the system image.
-PROGRAMS=	../kernel/kernel \
+PROGRAMS=	kernel \
 	../servers/ds/ds \
 	../servers/rs/rs \
 	../servers/pm/pm \
@ -42,7 +42,17 @@ usage:

 all: services image

+# for fast complie kernel and generate image, skip servers and drivers
+image_mb: includes
+	cd ../kernel && $(MAKE)
+	padtext ../kernel/kernel kernel
+	installboot -image $@ $(PROGRAMS)
+	
 image:  includes services
+	cd ../kernel && $(MAKE)
+	cd ../servers && $(MAKE) all
+	cd ../drivers && $(MAKE) all
+	padtext ../kernel/kernel kernel
 	installboot -image $@ $(PROGRAMS)

 # rebuild the program or system libraries
@ -79,7 +89,7 @@ clean:
 	$(MAKE) -C ../kernel $@
 	$(MAKE) -C ../servers $@
 	$(MAKE) -C ../drivers $@
-	rm -rf *.bak image *.iso *.iso.gz cdfdimage rootimage src
+	rm -rf *.bak image kernel *.iso *.iso.gz cdfdimage rootimage src

 cleandepend::
 	$(MAKE) -C ../kernel $@
--- a/tools/mkboot
+++ b/tools/mkboot
@ -109,6 +109,14 @@ hdboot)
 	echo "install image $root:/boot/image/$target"
 	install -o root -m 600 image $rootdir/boot/image/$target || exit

+	# Tell GRUB which image is newest
+	image_latest="`ls -t $rootdir/boot/image | head -n 1`"
+	if [ -f "$rootdir/boot/image/$image_latest" ]
+	then image_latest="/boot/image/$image_latest"
+	else image_latest=/boot/image_big
+	fi
+	ln -f $image_latest $rootdir/boot/image_latest
+
 	# Save the revision number.
 	test "$revision" != "$oldrev" && echo $revision >revision