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提交 89bfdd4d 创建 作者: Russ Cox's avatar Russ Cox
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multiboot support and memory-only (no disk) kernel

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Makefile
浏览文件 @ 89bfdd4d
...@@ -82,6 +82,11 @@ xv6.img: bootblock kernel fs.img ...@@ -82,6 +82,11 @@ xv6.img: bootblock kernel fs.img
dd if=bootblock of=xv6.img conv=notrunc dd if=bootblock of=xv6.img conv=notrunc
dd if=kernel of=xv6.img seek=1 conv=notrunc dd if=kernel of=xv6.img seek=1 conv=notrunc
xv6memfs.img: bootblock kernelmemfs
dd if=/dev/zero of=xv6memfs.img count=10000
dd if=bootblock of=xv6memfs.img conv=notrunc
dd if=kernelmemfs of=xv6memfs.img seek=1 conv=notrunc
bootblock: bootasm.S bootmain.c bootblock: bootasm.S bootmain.c
$(CC) $(CFLAGS) -fno-pic -O -nostdinc -I. -c bootmain.c $(CC) $(CFLAGS) -fno-pic -O -nostdinc -I. -c bootmain.c
$(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S $(CC) $(CFLAGS) -fno-pic -nostdinc -I. -c bootasm.S
...@@ -102,11 +107,23 @@ initcode: initcode.S ...@@ -102,11 +107,23 @@ initcode: initcode.S
$(OBJCOPY) -S -O binary initcode.out initcode $(OBJCOPY) -S -O binary initcode.out initcode
$(OBJDUMP) -S initcode.o > initcode.asm $(OBJDUMP) -S initcode.o > initcode.asm
kernel: $(OBJS) bootother initcode kernel: $(OBJS) multiboot.o bootother initcode
$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernel $(OBJS) -b binary initcode bootother $(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernel multiboot.o $(OBJS) -b binary initcode bootother fs.img
$(OBJDUMP) -S kernel > kernel.asm $(OBJDUMP) -S kernel > kernel.asm
$(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym $(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym
# kernelmemfs is a copy of kernel that maintains the
# disk image in memory instead of writing to a disk.
# This is not so useful for testing persistent storage or
# exploring disk buffering implementations, but it is
# great for testing the kernel on real hardware without
# needing a scratch disk.
MEMFSOBJS = $(filter-out ide.o,$(OBJS)) memide.o
kernelmemfs: $(MEMFSOBJS) multiboot.o bootother initcode fs.img
$(LD) $(LDFLAGS) -Ttext 0x100000 -e main -o kernelmemfs multiboot.o $(MEMFSOBJS) -b binary initcode bootother fs.img
$(OBJDUMP) -S kernelmemfs > kernelmemfs.asm
$(OBJDUMP) -t kernelmemfs | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernelmemfs.sym
tags: $(OBJS) bootother.S _init tags: $(OBJS) bootother.S _init
etags *.S *.c etags *.S *.c
...@@ -187,6 +204,9 @@ QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS) ...@@ -187,6 +204,9 @@ QEMUOPTS = -hdb fs.img xv6.img -smp $(CPUS)
qemu: fs.img xv6.img qemu: fs.img xv6.img
$(QEMU) -serial mon:stdio $(QEMUOPTS) $(QEMU) -serial mon:stdio $(QEMUOPTS)
qemu-memfs: xv6memfs.img
$(QEMU) xv6memfs.img -smp $(CPUS)
qemu-nox: fs.img xv6.img qemu-nox: fs.img xv6.img
$(QEMU) -nographic $(QEMUOPTS) $(QEMU) -nographic $(QEMUOPTS)
......
multiboot.S 0 → 100644
浏览文件 @ 89bfdd4d
# Multiboot header, for multiboot boot loaders like GNU Grub.
# http://www.gnu.org/software/grub/manual/multiboot/multiboot.html
#
# Using GRUB 2, you can boot xv6 from a file stored in a
# Linux file system by copying kernel or kernelmemfs to /boot
# and then adding this menu entry:
#
# menuentry "xv6" {
# insmod ext2
# set root='(hd0,msdos1)'
# set kernel='/boot/kernel'
# echo "Loading ${kernel}..."
# multiboot ${kernel} ${kernel}
# boot
# }
#include "asm.h"
#define STACK 4096
#define SEG_KCODE 1 // kernel code
#define SEG_KDATA 2 // kernel data+stack
# Multiboot header. Data to direct multiboot loader.
.p2align 2
.text
.globl multiboot_header
multiboot_header:
#define magic 0x1badb002
#define flags (1<<16 | 1<<0)
.long magic
.long flags
.long (-magic-flags)
.long multiboot_header # beginning of image
.long multiboot_header
.long edata
.long end
.long multiboot_entry
# Multiboot entry point. Machine is mostly set up.
# Configure the GDT to match the environment that our usual
# boot loader - bootasm.S - sets up.
.globl multiboot_entry
multiboot_entry:
lgdt gdtdesc
ljmp $(SEG_KCODE<<3), $mbstart32
mbstart32:
# Set up the protected-mode data segment registers
movw $(SEG_KDATA<<3), %ax # Our data segment selector
movw %ax, %ds # -> DS: Data Segment
movw %ax, %es # -> ES: Extra Segment
movw %ax, %ss # -> SS: Stack Segment
movw $0, %ax # Zero segments not ready for use
movw %ax, %fs # -> FS
movw %ax, %gs # -> GS
# Set up the stack pointer and call into C.
movl $(stack + STACK), %esp
call main
spin:
jmp spin
# Bootstrap GDT
.p2align 2 # force 4 byte alignment
gdt:
SEG_NULLASM # null seg
SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff) # code seg
SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg
gdtdesc:
.word (gdtdesc - gdt - 1) # sizeof(gdt) - 1
.long gdt # address gdt
.comm stack, STACK
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