38cd29ebd7
produced numerous problems in the past, including the fact that x86emu doesn't work in v3 anymore even though it lives in the v3 repository. Since this is a cross-repository move, keeping the history in the v2 tree would make life hard for everone. So check the v3 repository for x86emu history since the merger. The his commit is based on an svn export of r1175 of the coreboot-v3 repository. Signed-off-by: Stefan Reinauer <stepan@coresystems.de> Acked-by: Patrick Georgi <patrick.georgi@coresystems.de> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4532 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
345 lines
7.6 KiB
ArmAsm
345 lines
7.6 KiB
ArmAsm
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2009 coresystems GmbH
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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; version 2 of the License.
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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, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#define REALMODE_BASE 0x500
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#define RELOCATED(x) (x - __realmode_code + REALMODE_BASE)
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/* CR0 bits */
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#define PE (1 << 0)
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/* This is the intXX interrupt handler stub code. It gets copied
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* to the IDT and to some fixed addresses in the F segment. Before
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* the code can used, it gets patched up by the C function copying
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* it: byte 3 (the $0 in movb $0, %al) is overwritten with the int#.
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*/
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.code16
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.globl __idt_handler
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__idt_handler:
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pushal
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movb $0, %al /* This instruction gets modified */
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ljmp $0, $__interrupt_handler_16bit
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.globl __idt_handler_size
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__idt_handler_size = ( . - __idt_handler)
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/* In order to be independent of coreboot's position in RAM
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* we relocate a part of the code to the low megabyte, so the
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* CPU can use it in real-mode. This code lives at __realmode_code.
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*/
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.globl __realmode_code
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__realmode_code:
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/* Realmode IDT pointer structure. */
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.globl __realmode_idt
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__realmode_idt = RELOCATED(.)
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.word 1023 /* 16-bit limit */
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.long 0 /* 24-bit base */
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.word 0
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/* Preserve old stack */
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__stack = RELOCATED(.)
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.long 0
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.code32
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.globl __run_optionrom
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__run_optionrom = RELOCATED(.)
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/* save all registers to the stack */
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pushal
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/* Move the protected mode stack to a safe place */
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mov %esp, __stack
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/* Get devfn into %ecx */
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movl %esp, %ebp
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// FIXME: Should this function be called with regparm=0?
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movl 8(%ebp), %ecx
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/* Activate the right segment descriptor real mode. */
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ljmp $0x28, $RELOCATED(1f)
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1:
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.code16
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/* 16 bit code from here on... */
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/* Load the segment registers w/ properly configured
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* segment descriptors. They will retain these
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* configurations (limits, writability, etc.) once
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* protected mode is turned off.
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*/
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mov $0x30, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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/* Turn off protection */
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movl %cr0, %eax
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andl $~PE, %eax
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movl %eax, %cr0
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/* Now really going into real mode */
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ljmp $0, $RELOCATED(1f)
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1:
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/* Setup a stack: Put the stack at the end of page zero.
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* That way we can easily share it between real and
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* protected, since the 16-bit ESP at segment 0 will
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* work for any case. */
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mov $0x0, %ax
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mov %ax, %ss
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movl $0x1000, %eax
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movl %eax, %esp
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/* Load our 16 bit idt */
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xor %ax, %ax
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mov %ax, %ds
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lidt __realmode_idt
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/* Set all segments to 0x0000, ds to 0x0040 */
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov $0x40, %ax
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mov %ax, %ds
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mov %cx, %ax // restore ax
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/* ************************************ */
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// TODO this will not work for non-VGA option ROMs
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/* run VGA BIOS at 0xc000:0003 */
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lcall $0xc000, $0x0003
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/* ************************************ */
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/* If we got here, just about done.
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* Need to get back to protected mode
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*/
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movl %cr0, %eax
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orl $PE, %eax
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movl %eax, %cr0
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/* Now that we are in protected mode
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* jump to a 32 bit code segment.
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*/
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data32 ljmp $0x10, $RELOCATED(1f)
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1:
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.code32
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movw $0x18, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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/* restore proper idt */
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lidt idtarg
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/* and exit */
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mov __stack, %esp
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popal
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ret
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.globl __run_interrupt
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__run_interrupt = RELOCATED(.)
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/* paranoia -- does ecx get saved? not sure. This is
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* the easiest safe thing to do. */
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pushal
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/* save the stack */
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mov %esp, __stack
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/* This configures CS properly for real mode. */
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ljmp $0x28, $RELOCATED(1f)
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1:
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.code16 /* 16 bit code from here on... */
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// CONFIG_DEBUG
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movb $0xec, %al
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outb %al, $0x80
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/* Load the segment registers w/ properly configured segment
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* descriptors. They will retain these configurations (limits,
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* writability, etc.) once protected mode is turned off.
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*/
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mov $0x30, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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/* Turn off protected mode */
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movl %cr0, %eax
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andl $~PE, %eax
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movl %eax, %cr0
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/* Now really going into real mode */
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data32 ljmp $0, $RELOCATED(1f)
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1:
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/* put the stack at the end of page zero.
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* that way we can easily share it between real and protected,
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* since the 16-bit ESP at segment 0 will work for any case.
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*/
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/* setup a stack */
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mov $0x0, %ax
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mov %ax, %ss
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movl $0x1000, %eax
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movl %eax, %esp
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/* Load 16-bit intXX IDT */
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xor %ax, %ax
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mov %ax, %ds
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lidt __realmode_idt
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/* Set all segments to 0x0000 */
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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/* Call VGA BIOS int10 function 0x4f14 to enable main console
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* Epia-M does not always autosence the main console so forcing
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* it on is good.
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*/
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/* Ask VGA option rom to enable main console */
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movw $0x4f14,%ax
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movw $0x8003,%bx
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movw $1, %cx
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movw $0, %dx
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movw $0, %di
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int $0x10
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/* Ok, the job is done, now go back to protected mode coreboot */
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movl %cr0, %eax
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orl $PE, %eax
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movl %eax, %cr0
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/* Now that we are in protected mode jump to a 32-bit code segment. */
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data32 ljmp $0x10, $RELOCATED(1f)
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1:
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.code32
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movw $0x18, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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/* restore coreboot's 32-bit IDT */
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lidt idtarg
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/* Exit */
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mov __stack, %esp
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popal
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ret
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/* This is the 16-bit interrupt entry point called by the IDT stub code.
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* Before this code code is called, %eax is pushed to the stack, and the
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* interrupt number is loaded into %al
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*/
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.code16
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__interrupt_handler_16bit = RELOCATED(.)
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push %ds
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push %es
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push %fs
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push %gs
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/* Clean up the interrupt number. We could have done this in the stub,
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* but it would have cost 2 more bytes per stub entry.
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*/
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andl $0xff, %eax
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pushl %eax /* ... and make it the first parameter */
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/* Switch to protected mode */
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movl %cr0, %eax
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orl $PE, %eax
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movl %eax, %cr0
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/* ... and jump to a 32 bit code segment. */
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data32 ljmp $0x10, $RELOCATED(1f)
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1:
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.code32
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movw $0x18, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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lidt idtarg
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/* Call the C interrupt handler */
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movl $interrupt_handler, %eax
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call *%eax
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/* Now return to real mode ... */
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ljmp $0x28, $RELOCATED(1f)
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1:
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.code16
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/* Load the segment registers with properly configured segment
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* descriptors. They will retain these configurations (limits,
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* writability, etc.) once protected mode is turned off.
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*/
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mov $0x30, %ax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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/* Disable Protected Mode */
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movl %cr0, %eax
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andl $~PE, %eax
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movl %eax, %cr0
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/* Now really going into real mode */
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ljmp $0, $RELOCATED(1f)
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1:
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/* Restore real-mode stack segment */
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mov $0x0, %ax
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mov %ax, %ss
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/* Restore 16-bit IDT */
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xor %ax, %ax
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mov %ax, %ds
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lidt __realmode_idt
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/* Set up our segment registers to segment 0x0000 */
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov $0x40, %ax
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mov %ax, %ds
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/* Restore all registers, including those
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* manipulated by the C handler
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*/
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popl %eax
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pop %gs
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pop %fs
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pop %es
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pop %ds
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popal
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iret
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.globl __realmode_code_size
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__realmode_code_size = (. - __realmode_code)
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.code32
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