75b9f69057
Currently linuxboot.bin and multiboot.bin option roms override int19 vector to intercept boot process. No sane option rom should do that. Provide bev entry instead that will be called by BIOS if option rom is selected for booting. Signed-off-by: Gleb Natapov <gleb@redhat.com> Acked-by: Alexander Graf <agraf@suse.de> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
187 lines
4.1 KiB
ArmAsm
187 lines
4.1 KiB
ArmAsm
/*
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* Multiboot Option ROM
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright Novell Inc, 2009
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* Authors: Alexander Graf <agraf@suse.de>
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*/
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#include "optionrom.h"
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#define BOOT_ROM_PRODUCT "multiboot loader"
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#define MULTIBOOT_MAGIC 0x2badb002
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#define GS_PROT_JUMP 0
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#define GS_GDT_DESC 6
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BOOT_ROM_START
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run_multiboot:
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cli
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cld
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mov %cs, %eax
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shl $0x4, %eax
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/* set up a long jump descriptor that is PC relative */
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/* move stack memory to %gs */
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mov %ss, %ecx
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shl $0x4, %ecx
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mov %esp, %ebx
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add %ebx, %ecx
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sub $0x20, %ecx
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sub $0x30, %esp
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shr $0x4, %ecx
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mov %cx, %gs
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/* now push the indirect jump decriptor there */
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mov (prot_jump), %ebx
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add %eax, %ebx
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movl %ebx, %gs:GS_PROT_JUMP
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mov $8, %bx
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movw %bx, %gs:GS_PROT_JUMP + 4
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/* fix the gdt descriptor to be PC relative */
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movw (gdt_desc), %bx
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movw %bx, %gs:GS_GDT_DESC
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movl (gdt_desc+2), %ebx
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add %eax, %ebx
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movl %ebx, %gs:GS_GDT_DESC + 2
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xor %eax, %eax
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mov %eax, %es
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/* Read the bootinfo struct into RAM */
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read_fw_blob(FW_CFG_INITRD)
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/* FS = bootinfo_struct */
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read_fw FW_CFG_INITRD_ADDR
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shr $4, %eax
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mov %ax, %fs
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/* ES = mmap_addr */
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mov %fs:48, %eax
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shr $4, %eax
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mov %ax, %es
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/* Initialize multiboot mmap structs using int 0x15(e820) */
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xor %ebx, %ebx
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/* mmap start after first size */
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movl $4, %edi
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mmap_loop:
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/* entry size (mmap struct) & max buffer size (int15) */
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movl $20, %ecx
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/* store entry size */
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/* old as(1) doesn't like this insn so emit the bytes instead:
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movl %ecx, %es:-4(%edi)
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*/
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.dc.b 0x26,0x67,0x66,0x89,0x4f,0xfc
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/* e820 */
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movl $0x0000e820, %eax
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/* 'SMAP' magic */
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movl $0x534d4150, %edx
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int $0x15
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mmap_check_entry:
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/* last entry? then we're done */
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jb mmap_done
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and %bx, %bx
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jz mmap_done
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/* valid entry, so let's loop on */
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mmap_store_entry:
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/* %ax = entry_number * 24 */
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mov $24, %ax
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mul %bx
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mov %ax, %di
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movw %di, %fs:0x2c
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/* %di = 4 + (entry_number * 24) */
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add $4, %di
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jmp mmap_loop
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mmap_done:
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real_to_prot:
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/* Load the GDT before going into protected mode */
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lgdt:
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data32 lgdt %gs:GS_GDT_DESC
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/* get us to protected mode now */
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movl $1, %eax
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movl %eax, %cr0
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/* the LJMP sets CS for us and gets us to 32-bit */
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ljmp:
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data32 ljmp *%gs:GS_PROT_JUMP
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prot_mode:
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.code32
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/* initialize all other segments */
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movl $0x10, %eax
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movl %eax, %ss
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movl %eax, %ds
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movl %eax, %es
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movl %eax, %fs
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movl %eax, %gs
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/* Read the kernel and modules into RAM */
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read_fw_blob(FW_CFG_KERNEL)
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/* Jump off to the kernel */
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read_fw FW_CFG_KERNEL_ENTRY
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mov %eax, %ecx
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/* EBX contains a pointer to the bootinfo struct */
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read_fw FW_CFG_INITRD_ADDR
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movl %eax, %ebx
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/* EAX has to contain the magic */
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movl $MULTIBOOT_MAGIC, %eax
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ljmp2:
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jmp *%ecx
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/* Variables */
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.align 4, 0
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prot_jump: .long prot_mode
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.short 8
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.align 4, 0
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gdt:
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/* 0x00 */
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.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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/* 0x08: code segment (base=0, limit=0xfffff, type=32bit code exec/read, DPL=0, 4k) */
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.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00
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/* 0x10: data segment (base=0, limit=0xfffff, type=32bit data read/write, DPL=0, 4k) */
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.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00
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/* 0x18: code segment (base=0, limit=0x0ffff, type=16bit code exec/read/conf, DPL=0, 1b) */
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.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9e, 0x00, 0x00
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/* 0x20: data segment (base=0, limit=0x0ffff, type=16bit data read/write, DPL=0, 1b) */
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.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0x00, 0x00
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gdt_desc:
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.short (5 * 8) - 1
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.long gdt
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BOOT_ROM_END
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