mirror of
https://github.com/fail0verflow/switch-coreboot.git
synced 2025-05-04 01:39:18 -04:00
61cd5ae455
Carl-Daniel Hailfinger wrote: > On 18.02.2008 23:55, Marc Jones wrote: >> Carl-Daniel Hailfinger wrote: >>> it seems that executing VSA requires vm86 to be useful. Since we >>> unconditionally execute the VSA, we should unconditionally require vm86 >>> support (PCI_OPTION_ROM_RUN_VM86) via Kconfig for Geode targets. Not >>> doing so will either cause compile failures or runtime failures. >>> >>> Adding >>> select PCI_OPTION_ROM_RUN_VM86 >>> below >>> config CPU_AMD_GEODELX >>> did not work out for me. >> Sorry I missed this. >> >> VSA requires the GDT that is in vm86.c. VSA loads similar to an option >> ROM so the loader does go into VM86 mode. All the other stuff like >> interrupt support and PCI BIOS isn't needed by VSA. I think that the >> GDT at the top of vm86.c can be moved to a header file, gdt.h or >> something like that. > > northbridge/amd/geodelx/vsmsetup.c uses > util/x86emu/vm86.c:setup_realmode_idt() but it seems most/all of the > setup there is not needed at all for VSA. Pulling in setup_realmode_idt > pulls in the rest of vm86 through direct and indirect dependencies. > >> Care to make a patch? :) > I am also leaning towards removing the IDT for VSA init. There is a risk if either an exception happens or a software interrupt is used you will get unexpected results. What probably happens is that you jump off to something that will eventually cause a triple fault and reboot. You may think this is bad (and it is) but it is the same risk that coreboot runs today. If coreboot had a generic IDT to handle exceptions, VSA init would use the same IDT. Note that hardware INT (even timers) should never happen as they are always masked. I have built with no PCI_OPTION_ROM_RUN_VM86 and run this to filo. - Show quoted text - Marc -- Marc Jones Senior Firmware Engineer (970) 226-9684 Office mailto:Marc.Jones@amd.com http://www.amd.com/embeddedprocessors Reduce the amount of compilation errors for Geode LX targets if x86emu or no emulation is selected instead of vm86. Factor out GDT code from vm86.c to vm86_gdt.c Remove IDT setup for VSA init. Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> Signed-of-by: Marc Jones <marc.jones@amd.com> This has booted to runlevel 3 and the ethernet works fine. Acked-by: Ronald G. Minnich <rminnich@gmail.com> git-svn-id: svn://coreboot.org/repository/coreboot-v3@613 f3766cd6-281f-0410-b1cd-43a5c92072e9
95 lines
2.7 KiB
C
95 lines
2.7 KiB
C
/*
|
|
* Erik Arjan Hendriks <hendriks@lanl.gov>
|
|
* Copyright (C) 2000 Scyld.
|
|
* Copyright (C) 2000 Scyld Computing Corporation
|
|
* Copyright (C) 2001 University of California. LA-CC Number 01-67.
|
|
* Copyright (C) 2005 Nick.Barker9@btinternet.com
|
|
* Copyright (C) 2007 coresystems GmbH
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
*/
|
|
|
|
|
|
/* Declare a temporary global descriptor table -
|
|
* necessary because the core part of the bios
|
|
* no longer sets up any 16 bit segments
|
|
*/
|
|
|
|
__asm__ (
|
|
/* pointer to original gdt */
|
|
" .globl gdtarg\n"
|
|
"gdtarg: \n"
|
|
" .word gdt_limit \n"
|
|
" .long gdtptr \n"
|
|
|
|
/* compute the table limit */
|
|
"__mygdt_limit = __mygdt_end - __mygdt - 1 \n"
|
|
" .globl __mygdtaddr\n"
|
|
"__mygdtaddr: \n"
|
|
" .word __mygdt_limit \n"
|
|
" .long __mygdt \n"
|
|
|
|
" .globl __mygdt\n"
|
|
"__mygdt: \n"
|
|
/* selgdt 0, unused */
|
|
" .word 0x0000, 0x0000 \n"
|
|
" .byte 0x00, 0x00, 0x00, 0x00 \n"
|
|
|
|
/* selgdt 8, unused */
|
|
" .word 0x0000, 0x0000 \n"
|
|
" .byte 0x00, 0x00, 0x00, 0x00 \n"
|
|
|
|
/* selgdt 0x10, flat code segment */
|
|
" .word 0xffff, 0x0000 \n"
|
|
" .byte 0x00, 0x9b, 0xcf, 0x00 \n"
|
|
|
|
/* selgdt 0x18, flat data segment */
|
|
" .word 0xffff, 0x0000 \n"
|
|
" .byte 0x00, 0x93, 0xcf, 0x00 \n"
|
|
|
|
/* selgdt 0x20, unused */
|
|
" .word 0x0000, 0x0000 \n"
|
|
" .byte 0x00, 0x00, 0x00, 0x00 \n"
|
|
|
|
/* selgdt 0x28 16-bit 64k code at 0x00000000 */
|
|
" .word 0xffff, 0x0000 \n"
|
|
" .byte 0, 0x9a, 0, 0 \n"
|
|
|
|
/* selgdt 0x30 16-bit 64k data at 0x00000000 */
|
|
" .word 0xffff, 0x0000 \n"
|
|
" .byte 0, 0x92, 0, 0 \n"
|
|
|
|
"__mygdt_end: \n"
|
|
|
|
/* FIXME: This does probably not belong here */
|
|
" .globl idtarg\n"
|
|
"idtarg:\n"
|
|
" .word _idt_end - _idt - 1\n" /* limit */
|
|
" .long _idt\n"
|
|
" .word 0\n"
|
|
"_idt:\n"
|
|
" .fill 20, 8, 0\n" // # idt is unitiailzed
|
|
"_idt_end:\n"
|
|
|
|
/* Declare a pointer to where our idt is going to be i.e. at mem zero */
|
|
" .globl __myidt\n"
|
|
"__myidt: \n"
|
|
/* 16-bit limit */
|
|
" .word 1023 \n"
|
|
/* 24-bit base */
|
|
" .long 0 \n"
|
|
" .word 0 \n"
|
|
);
|