Ronald G. Minnich 61cd5ae455 This discussion is too useful to lose. ... 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		2008-02-21 05:20:14 +00:00
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include/x86emu	Now version 3: LinuxBIOS -> coreboot rename.	2008-01-27 18:54:57 +00:00
pcbios	The commit in r558 had this:	2008-02-20 13:33:36 +00:00
x86emu	Now version 3: LinuxBIOS -> coreboot rename.	2008-01-27 18:54:57 +00:00
biosemu.c	Now version 3: LinuxBIOS -> coreboot rename.	2008-01-27 18:54:57 +00:00
Makefile	This discussion is too useful to lose.	2008-02-21 05:20:14 +00:00
vm86.c	This discussion is too useful to lose.	2008-02-21 05:20:14 +00:00
vm86_gdt.c	This discussion is too useful to lose.	2008-02-21 05:20:14 +00:00