diff options
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/boot/header.S | 283 | ||||
| -rw-r--r-- | arch/i386/boot/main.c | 161 |
2 files changed, 444 insertions, 0 deletions
diff --git a/arch/i386/boot/header.S b/arch/i386/boot/header.S new file mode 100644 index 00000000000..6b9923fb6ea --- /dev/null +++ b/arch/i386/boot/header.S @@ -0,0 +1,283 @@ +/* + * header.S + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * Based on bootsect.S and setup.S + * modified by more people than can be counted + * + * Rewritten as a common file by H. Peter Anvin (Apr 2007) + * + * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment + * addresses must be multiplied by 16 to obtain their respective linear + * addresses. To avoid confusion, linear addresses are written using leading + * hex while segment addresses are written as segment:offset. + * + */ + +#include <asm/segment.h> +#include <linux/utsrelease.h> +#include <asm/boot.h> +#include <asm/e820.h> +#include <asm/page.h> +#include <asm/setup.h> +#include "boot.h" + +SETUPSECTS = 4 /* default nr of setup-sectors */ +BOOTSEG = 0x07C0 /* original address of boot-sector */ +SYSSEG = DEF_SYSSEG /* system loaded at 0x10000 (65536) */ +SYSSIZE = DEF_SYSSIZE /* system size: # of 16-byte clicks */ + /* to be loaded */ +ROOT_DEV = 0 /* ROOT_DEV is now written by "build" */ +SWAP_DEV = 0 /* SWAP_DEV is now written by "build" */ + +#ifndef SVGA_MODE +#define SVGA_MODE ASK_VGA +#endif + +#ifndef RAMDISK +#define RAMDISK 0 +#endif + +#ifndef ROOT_RDONLY +#define ROOT_RDONLY 1 +#endif + + .code16 + .section ".bstext", "ax" + + .global bootsect_start +bootsect_start: + + # Normalize the start address + ljmp $BOOTSEG, $start2 + +start2: + movw %cs, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %ss + xorw %sp, %sp + sti + cld + + movw $bugger_off_msg, %si + +msg_loop: + lodsb + andb %al, %al + jz bs_die + movb $0xe, %ah + movw $7, %bx + int $0x10 + jmp msg_loop + +bs_die: + # Allow the user to press a key, then reboot + xorw %ax, %ax + int $0x16 + int $0x19 + + # int 0x19 should never return. In case it does anyway, + # invoke the BIOS reset code... + ljmp $0xf000,$0xfff0 + + .section ".bsdata", "a" +bugger_off_msg: + .ascii "Direct booting from floppy is no longer supported.\r\n" + .ascii "Please use a boot loader program instead.\r\n" + .ascii "\n" + .ascii "Remove disk and press any key to reboot . . .\r\n" + .byte 0 + + + # Kernel attributes; used by setup. This is part 1 of the + # header, from the old boot sector. + + .section ".header", "a" + .globl hdr +hdr: +setup_sects: .byte SETUPSECTS +root_flags: .word ROOT_RDONLY +syssize: .long SYSSIZE +ram_size: .word RAMDISK +vid_mode: .word SVGA_MODE +root_dev: .word ROOT_DEV +boot_flag: .word 0xAA55 + + # offset 512, entry point + + .globl _start +_start: + # Explicitly enter this as bytes, or the assembler + # tries to generate a 3-byte jump here, which causes + # everything else to push off to the wrong offset. + .byte 0xeb # short (2-byte) jump + .byte start_of_setup-1f +1: + + # Part 2 of the header, from the old setup.S + + .ascii "HdrS" # header signature + .word 0x0206 # header version number (>= 0x0105) + # or else old loadlin-1.5 will fail) + .globl realmode_swtch +realmode_swtch: .word 0, 0 # default_switch, SETUPSEG +start_sys_seg: .word SYSSEG + .word kernel_version-512 # pointing to kernel version string + # above section of header is compatible + # with loadlin-1.5 (header v1.5). Don't + # change it. + +type_of_loader: .byte 0 # = 0, old one (LILO, Loadlin, + # Bootlin, SYSLX, bootsect...) + # See Documentation/i386/boot.txt for + # assigned ids + +# flags, unused bits must be zero (RFU) bit within loadflags +loadflags: +LOADED_HIGH = 1 # If set, the kernel is loaded high +CAN_USE_HEAP = 0x80 # If set, the loader also has set + # heap_end_ptr to tell how much + # space behind setup.S can be used for + # heap purposes. + # Only the loader knows what is free +#ifndef __BIG_KERNEL__ + .byte 0 +#else + .byte LOADED_HIGH +#endif + +setup_move_size: .word 0x8000 # size to move, when setup is not + # loaded at 0x90000. We will move setup + # to 0x90000 then just before jumping + # into the kernel. However, only the + # loader knows how much data behind + # us also needs to be loaded. + +code32_start: # here loaders can put a different + # start address for 32-bit code. +#ifndef __BIG_KERNEL__ + .long 0x1000 # 0x1000 = default for zImage +#else + .long 0x100000 # 0x100000 = default for big kernel +#endif + +ramdisk_image: .long 0 # address of loaded ramdisk image + # Here the loader puts the 32-bit + # address where it loaded the image. + # This only will be read by the kernel. + +ramdisk_size: .long 0 # its size in bytes + +bootsect_kludge: + .long 0 # obsolete + +heap_end_ptr: .word _end+1024 # (Header version 0x0201 or later) + # space from here (exclusive) down to + # end of setup code can be used by setup + # for local heap purposes. + +pad1: .word 0 +cmd_line_ptr: .long 0 # (Header version 0x0202 or later) + # If nonzero, a 32-bit pointer + # to the kernel command line. + # The command line should be + # located between the start of + # setup and the end of low + # memory (0xa0000), or it may + # get overwritten before it + # gets read. If this field is + # used, there is no longer + # anything magical about the + # 0x90000 segment; the setup + # can be located anywhere in + # low memory 0x10000 or higher. + +ramdisk_max: .long (-__PAGE_OFFSET-(512 << 20)-1) & 0x7fffffff + # (Header version 0x0203 or later) + # The highest safe address for + # the contents of an initrd + +kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment + #required for protected mode + #kernel +#ifdef CONFIG_RELOCATABLE +relocatable_kernel: .byte 1 +#else +relocatable_kernel: .byte 0 +#endif +pad2: .byte 0 +pad3: .word 0 + +cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line, + #added with boot protocol + #version 2.06 + +# End of setup header ##################################################### + + .section ".inittext", "ax" +start_of_setup: +#ifdef SAFE_RESET_DISK_CONTROLLER +# Reset the disk controller. + movw $0x0000, %ax # Reset disk controller + movb $0x80, %dl # All disks + int $0x13 +#endif + +# We will have entired with %cs = %ds+0x20, normalize %cs so +# it is on par with the other segments. + pushw %ds + pushw $setup2 + lretw + +setup2: +# Force %es = %ds + movw %ds, %ax + movw %ax, %es + cld + +# Stack paranoia: align the stack and make sure it is good +# for both 16- and 32-bit references. In particular, if we +# were meant to have been using the full 16-bit segment, the +# caller might have set %sp to zero, which breaks %esp-based +# references. + andw $~3, %sp # dword align (might as well...) + jnz 1f + movw $0xfffc, %sp # Make sure we're not zero +1: movzwl %sp, %esp # Clear upper half of %esp + sti + +# Check signature at end of setup + cmpl $0x5a5aaa55, setup_sig + jne setup_bad + +# Zero the bss + movw $__bss_start, %di + movw $_end+3, %cx + xorl %eax, %eax + subw %di, %cx + shrw $2, %cx + rep; stosl + +# Jump to C code (should not return) + calll main + +# Setup corrupt somehow... +setup_bad: + movl $setup_corrupt, %eax + calll puts + # Fall through... + + .globl die + .type die, @function +die: + hlt + jmp die + + .size die, .-due + + .section ".initdata", "a" +setup_corrupt: + .byte 7 + .string "No setup signature found..." diff --git a/arch/i386/boot/main.c b/arch/i386/boot/main.c new file mode 100644 index 00000000000..7f01f96c4fb --- /dev/null +++ b/arch/i386/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_speedstep_ist(void) +{ + asm("int $0x15" + : "=a" (boot_params.speedstep_info[0]), + "=b" (boot_params.speedstep_info[1]), + "=c" (boot_params.speedstep_info[2]), + "=d" (boot_params.speedstep_info[3]) + : "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 SpeedStep IST information */ + query_speedstep_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(); +} |