Hmm...that code is kinda crappy, sorry. I copied it from someone else's
stuff. Looks like I need to do a review.
On Thu, Mar 6, 2014 at 4:26 AM, Thomas Rognon <tcrog...@gmail.com> wrote:
> If I were to wager, I would say that your computer does load PCI op roms.
> Most general purpose home/work computers do. I could be wrong, but if I
> were you I'd give it a try.
>
> One thing to keep in mind ... drivers probably have not been connected to
> their devices yet when loading PCI op roms, so you won't be able to use a
> lot of stuff like printing to the screen unless you call it yourself first
> in your driver. Here is code to do that (this came from somewhere in edk2 I
> think):
>
> EFI_STATUS
> EFIAPI
> ConnectAllEfi (
> VOID
> )
> {
> EFI_STATUS Status;
> UINTN HandleCount;
> EFI_HANDLE *HandleBuffer;
> UINTN Index;
>
> Status = gBS->LocateHandleBuffer (
> AllHandles,
> NULL,
> NULL,
> &HandleCount,
> &HandleBuffer
> );
> if (EFI_ERROR (Status)) {
> return Status;
> }
>
> for (Index = 0; Index < HandleCount; Index++) {
> Status = gBS->ConnectController (HandleBuffer[Index], NULL, NULL,
> TRUE);
> }
>
> if (HandleBuffer != NULL) {
> FreePool (HandleBuffer);
> }
>
> return EFI_SUCCESS;
> }
>
>
> On Thu, Mar 6, 2014 at 4:08 AM, Bill Paul <wp...@windriver.com> wrote:
>
>> Of all the gin joints in all the towns in all the world, Andrew Fish had
>> to
>> walk into mine at 18:02:30 on Wednesday 05 March 2014 and say:
>>
>> > On Mar 5, 2014, at 5:53 PM, Bill Paul <wp...@windriver.com> wrote:
>> > > Of all the gin joints in all the towns in all the world, Carsey, Jaben
>> > > had to
>> > >
>> > > walk into mine at 17:26:07 on Wednesday 05 March 2014 and say:
>> > >> A driver is able to do this, but whether your driver gets loaded and
>> run
>> > >> is a platform policy decision and may be different for your tablet.
>> > >
>> > > Can you elaborate? Where is the policy controlled from?
>> >
>> > The platform OEM. If you always new you would only support booting from
>> > internal devices, then disabling running a ROM from the PCIe slot
>> improves
>> > security.
>>
>> Okay, I have to ask this: are you speaking from experience, or is this
>> speculation based on what you've read/heard? Have you actually seen a UEFI
>> (non-Apple) machine that avoids loading drivers from PCI devices?
>>
>> I'm surprised that this would be the case, because the last time I read
>> through the UEFI spec, I saw several references to PCI option ROM
>> loading, but
>> I don't remember seeing anything about it being platform-dependent.
>>
>> > Does your tablet have an RTC with a battery backup? Maybe you could pull
>> > the battery, and maybe reseting the RTC CMOS would trigger some kind of
>> > recovery action? Just a wild guess.
>>
>> As a wise squirrel once said: "Aw Bullwinkle, that' trick _never_ works."
>>
>> Believe me: I've been there, I've done that, and the t-shirt didn't fit.
>> Unplugging the backup battery had no effect on either the tablet or the
>> Emerson MATXM-411 development board that I bricked with the same buggy
>> code.
>> The Emerson board at least has a jumper to activate a BIOS recovery
>> mechanism
>> -- you can re-flash the firmware via serial port, and the recovery option
>> is
>> presented before it gets hung -- but that didn't help either: I was able
>> to
>> re-flash the firmware, but that apparently wouldn't clear the NVRAM. I was
>> only able to un-wedge it using JTAG.
>>
>> The tablet, by the way, is an ExoPC Slate. It was actually Intel's MeeGo
>> development platform.
>>
>> > On a Mac you do cmd-opt-P-R to reset this kind of thing, but you are in
>> the
>> > area of platform specific behavior. So it is hard for us to give too
>> much
>> > concrete advice....
>>
>> I find it ironic that the ability to brick the firmware is not platform-
>> dependent, but the ability to recover it is.
>>
>> I was hoping someone would at least answer my original question: assuming
>> that
>> the firmware does load and run drivers from PCI devices, does this occur
>> before the Bds code runs or after?
>>
>> Also, I'm not convinced the Apple EFI implementation would be able to
>> recover
>> from this either. Anything's possible, but the only way to find out is to
>> test
>> it and I'm unwilling to risk it unless I know for sure I have some way to
>> recover the machine.
>>
>> -Bill
>>
>>
>> > Good Luck,
>> >
>> > Andrew Fish
>> >
>> > > I know that some UEFI firmware implementations have a setup menu
>> option
>> > > to enable/disable loading of option ROMs, but it's not clear to me if
>> > > this applies only to BIOS option ROMs -- usually it affects whether or
>> > > not the PXE ROM is loaded. And the setup menu on this tablet is very
>> > > limited -- I'm pretty sure it didn't have any option to configure
>> this.
>> > >
>> > >> If you go ahead with it, you may borrow some code from the shell's
>> BCFG
>> > >> command for BOOTXXXX variable manipulation.
>> > >
>> > > Oh I already know how to handle this with gBS->SetVariable(). (That's
>> > > what got me into this mess in the first place.)
>> > >
>> > > -Bill
>> > >
>> > >> -Jaben
>> > >>
>> > >> -----Original Message-----
>> > >> From: Bill Paul [mailto:wp...@windriver.com]
>> > >> Sent: Wednesday, March 05, 2014 5:12 PM
>> > >> To: edk2-devel@lists.sourceforge.net
>> > >> Subject: [edk2] Question about firmware startup order of events
>> > >>
>> > >> You may recall that I mentioned that due to a mishap with some UEFI
>> OS
>> > >> loader code I was developing, I managed to brick my UEFI-based
>> tablet by
>> > >> setting an improperly formatted boot path variable as the default
>> boot
>> > >> path.
>> > >>
>> > >> Unfortunately unplugging the internal SSD drive didn't have any
>> effect,
>> > >> and I haven't been able to think of a way to directly re-whack the
>> > >> NVRAM, and I don't have a way to hook my JTAG probe to it. I did
>> think
>> > >> of one potential way around the problem, but there's something I need
>> > >> to clarify first.
>> > >>
>> > >> The tablet has wifi support, in the form of an Atheros mini-PCIe
>> adapter
>> > >> which is plugged into the main board. This adapter can be easily
>> > >> unplugged and replaced.
>> > >>
>> > >> What I'm considering is using the EDK2 to cobble together a UEFI
>> driver
>> > >> with just enough code in it to erase the BootXXXX and BootOrder
>> > >> variables and flashing it to some device which I can fit into this
>> > >> mini-PCIe slot, in the hopes that I can get the firmware to run this
>> > >> code for me.
>> > >>
>> > >> But this will only work if the driver is loaded and executed before
>> the
>> > >> firmware gets to the boot device selection code. Conceptually it
>> would
>> > >> seem that this would be the case (I mean, you need to load the
>> drivers
>> > >> for devices before you can use them as boot paths, right?) but I'm
>> not
>> > >> positive if this so.
>> > >>
>> > >> Can anyone tell me if this idea has a chance of working? It costs me
>> > >> nothing to tinker around with the EDK2, but it would cost me a
>> little do
>> > >> obtain a suitable PCIe device, so I want to check before I end up
>> > >> spending money for nothing.
>> > >>
>> > >> -Bill
>> > >>
>> > >> --
>> > >>
>> ========================================================================
>> > >> === == -Bill Paul (510) 749-2329 | Senior Member of
>> Technical
>> > >> Staff, wp...@windriver.com | Master of Unix-Fu - Wind River Systems
>> > >>
>> ========================================================================
>> > >> == === "I put a dollar in a change machine. Nothing changed." -
>> George
>> > >> Carlin
>> > >>
>> =======================================================================
>> > >> === ===
>> > >>
>> > >>
>> ------------------------------------------------------------------------
>> > >> --- --- Subversion Kills Productivity. Get off Subversion & Make the
>> > >> Move to Perforce. With Perforce, you get hassle-free workflows. Merge
>> > >> that actually works. Faster operations. Version large binaries.
>> > >> Built-in WAN optimization and the freedom to use Git, Perforce or
>> both.
>> > >> Make the move to Perforce.
>> > >>
>> http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.cl
>> > >> kt rk _______________________________________________
>> > >> edk2-devel mailing list
>> > >> edk2-devel@lists.sourceforge.net
>> > >> https://lists.sourceforge.net/lists/listinfo/edk2-devel
>> > >>
>> > >>
>> ------------------------------------------------------------------------
>> > >> --- --- Subversion Kills Productivity. Get off Subversion & Make the
>> > >> Move to Perforce. With Perforce, you get hassle-free workflows. Merge
>> > >> that actually works. Faster operations. Version large binaries.
>> > >> Built-in WAN optimization and the freedom to use Git, Perforce or
>> both.
>> > >> Make the move to Perforce.
>> > >>
>> http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.cl
>> > >> ktr k _______________________________________________
>> > >> edk2-devel mailing list
>> > >> edk2-devel@lists.sourceforge.net
>> > >> https://lists.sourceforge.net/lists/listinfo/edk2-devel
>>
>> --
>>
>> =============================================================================
>> -Bill Paul (510) 749-2329 | Senior Member of Technical Staff,
>> wp...@windriver.com | Master of Unix-Fu - Wind River
>> Systems
>>
>> =============================================================================
>> "I put a dollar in a change machine. Nothing changed." - George Carlin
>>
>> =============================================================================
>>
>>
>> ------------------------------------------------------------------------------
>> Subversion Kills Productivity. Get off Subversion & Make the Move to
>> Perforce.
>> With Perforce, you get hassle-free workflows. Merge that actually works.
>> Faster operations. Version large binaries. Built-in WAN optimization and
>> the
>> freedom to use Git, Perforce or both. Make the move to Perforce.
>>
>> http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk
>> _______________________________________________
>> edk2-devel mailing list
>> edk2-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/edk2-devel
>>
>
>
------------------------------------------------------------------------------
Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce.
With Perforce, you get hassle-free workflows. Merge that actually works.
Faster operations. Version large binaries. Built-in WAN optimization and the
freedom to use Git, Perforce or both. Make the move to Perforce.
http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk
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