Re: EFI from usb HDD

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Fri, Jul 30, 2021 at 08:22:18AM +0200, Michal Simek wrote:
> 
> 
> On 7/30/21 7:33 AM, AKASHI Takahiro wrote:
> > On Fri, Jul 30, 2021 at 06:41:01AM +0200, Michal Simek wrote:
> >>
> >>
> >> On 7/30/21 4:35 AM, AKASHI Takahiro wrote:
> >>> On Thu, Jul 29, 2021 at 04:09:32PM +0200, Michal Simek wrote:
> >>>> Hi,
> >>>>
> >>>> On 6/10/21 2:59 PM, AKASHI Takahiro wrote:
> >>>>> On Thu, Jun 10, 2021 at 02:31:46PM +0200, Michal Simek wrote:
> >>>>>>
> >>>>>>
> >>>>>> On 6/10/21 12:51 PM, Heinrich Schuchardt wrote:
> >>>>>>> On 6/10/21 12:04 PM, Michal Simek wrote:
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> On 6/10/21 11:47 AM, Heinrich Schuchardt wrote:
> >>>>>>>>> On 6/10/21 10:44 AM, Michal Simek wrote:
> >>>>>>>>>> Hi,
> >>>>>>>>>>
> >>>>>>>>>> I am playing with booting from USB via EFI. And I see very weird
> >>>>>>>>>> behavior. I have burnt image with grub to USB flashdisk and I have
> >>>>>>>>>> tested it on 3 zynqmp boards. zcu102, zcu104 and SOM Kria board.
> >>>>>>>>>> On zcu102 grub is going to boot menu and everything is working fine as
> >>>>>>>>>> expected.
> >>>>>>>>>> On zcu104 and SOM Kria I am able to get grub not to menu. When I list
> >>>>>>>>>> partitions in grub I see that only SDs are listed:
> >>>>>>>>>> grub> ls
> >>>>>>>>>> (hd0) (hd0,msdos1) (hd1) (hd1,msdos1)
> >>>>>>>>>
> >>>>>>>>> Hello Michal,
> >>>>>>>>>
> >>>>>>>>> thanks for sharing your observations.
> >>>>>>>>>
> >>>>>>>>> What devices do hd0 and hd1 relate to?
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> On zcu102(working board) I also see usb(gpt) partitions and SD.
> >>>>>>>>>> grub> ls
> >>>>>>>>>> (hd0) (hd0,gpt2) (hd0,gpt1) (hd1) (hd1,msdos1)
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> GPT and MBR partitioning are independent of the device type.
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> On zcu104 I see one more error message
> >>>>>>>>>> "PE image measurement failed"
> >>>>>>>>>
> >>>>>>>>> This is related to CONFIG_EFI_TCG2_PROTOCOL=y. Do you have a TPMv2? This
> >>>>>>>>> will not stop disk enumeration.
> >>>>>>>>>
> >>>>>>>>>> But I can't see it on SOM.
> >>>>>>>>>>
> >>>>>>>>>> U-Boot image is just the same for all boards. I am using generic
> >>>>>>>>>> xilinx_zynqmp_virt_defconfig.
> >>>>>>>>>>
> >>>>>>>>>> When I compare DT description for USB between zcu102 and zcu104 they
> >>>>>>>>>> are
> >>>>>>>>>> the same. SOM doesn't have usb enabled by default (but I enabled it)
> >>>>>>>>>> but
> >>>>>>>>>> grub starts which means that communication with USB is fine.
> >>>>>>>>>>
> >>>>>>>>>> It is based on my latest patches available here.
> >>>>>>>>>> u-boot/custodians/u-boot-microblaze.git (usb-efi-issue branch)
> >>>>>>>>>>
> >>>>>>>>>> Also when I list usb I see all partitions just fine.
> >>>>>>>>>> ZynqMP> part list usb 0
> >>>>>>>>>>
> >>>>>>>>>> Partition Map for USB device 0  --   Partition Type: EFI
> >>>>>>>>>>
> >>>>>>>>>> Part    Start LBA       End LBA         Name
> >>>>>>>>>>           Attributes
> >>>>>>>>>>           Type GUID
> >>>>>>>>>>           Partition GUID
> >>>>>>>>>>     1     0x00000800      0x001007fe      "Microsoft basic data"
> >>>>>>>>>>           attrs:  0x0000000000000000
> >>>>>>>>>>           type:   ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
> >>>>>>>>>>           type:   data
> >>>>>>>>>>           guid:   0e7f8b3d-296b-4720-be9d-c4687d3c4a77
> >>>>>>>>>>     2     0x00100800      0x001197fe      "Microsoft basic data"
> >>>>>>>>>>           attrs:  0x0000000000000000
> >>>>>>>>>>           type:   ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
> >>>>>>>>>>           type:   data
> >>>>>>>>>>           guid:   8892eddc-231a-4e6e-a5e1-c310f4482fb7
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> Do you have any idea why on one system is working fine to get to menu
> >>>>>>>>>> and on others there is an issue to get all partitions even u-boot is
> >>>>>>>>>> able to see them and can work with them.
> >>>>>>>>>>
> >>>>>>>>>> Thanks,
> >>>>>>>>>> Michal
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Where is the GRUB binary? - If it is in EFI/boot/bootaa64.efi, it could
> >>>>>>>>> be that the USB sub-system is simply not initialized yet when the boot
> >>>>>>>>> manager is called by distroboot.
> >>>>>>>>>
> >>>>>>>>> For testing partition detection in the UEFI sub-system it is enough
> >>>>>>>>> to run
> >>>>>>>>>
> >>>>>>>>>      efidebug devices
> >>>>>>>>>
> >>>>>>>>> Until yesterday we had a problem with partition numbers >= 10, cf.
> >>>>>>>>>
> >>>>>>>>> efi_loader: partition numbers are hexadecimal
> >>>>>>>>> https://source.denx.de/u-boot/u-boot/-/commit/3dca77b1dc1b6dbf9c8b51572fe4b0553cef009f
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Block devices are enumerated in efi_disk_register(). Please, try to add
> >>>>>>>>> debug output there to elucidate the problem.
> >>>>>>>>
> >>>>>>>> I found where the problem is. First of all zcu102 didn't use the same
> >>>>>>>> image as others (it wasn't updated properly).
> >>>>>>>> When you have CONFIG_EFI_CAPSULE_ON_DISK_EARLY that efi_disk_register()
> >>>>>>>> is called before usb block devices are detected and registered that's
> >>>>>>>> why grub doesn't see them.
> >>>>>>>
> >>>>>>> The problem is CONFIG_EFI_SETUP_EARLY=y required by
> >>>>>>> CONFIG_EFI_CAPSULE_ON_DISK_EARLY.
> >>>>>>>
> >>>>>>> Why is USB initialized later then MMC?
> >>>>>>
> >>>>>> It is not just usb. SCSI/sata are behaving in the same way too.
> >>>>>>
> >>>>>>>
> >>>>>>> Overall we have a deficiency in the UEFI implementation in that we
> >>>>>>> cannot deal with block devices added or removed after initialization.
> >>>>>>>
> >>>>>>> Here integration with the driver model is missing.
> >>>>>>
> >>>>>> Right. And also there are commands which can create MBR partitions and I
> >>>>>> expect when you write image to SD and then run rescan or so you could
> >>>>>> get other partitions too.
> >>>>>> Maybe hook via part_init()? with removing efi_disk_register.
> >>>>>
> >>>>> For the record, I have proposed my ideas several times[1], [2].
> >>>>> I'm, however, no longer working on this issue as I have shifted
> >>>>> my focus to UEFI secure boot and capsule update.
> >>>>>
> >>>>> -Takahiro Akashi
> >>>>>
> >>>>> [1] https://lists.denx.de/pipermail/u-boot/2018-November/347491.html
> >>>>> [2] https://lists.denx.de/pipermail/u-boot/2019-February/357923.html
> >>>>
> >>>> I want to continue on this thread. I have disabled
> >>>> EFI_CAPSULE_ON_DISK_EARLY some time ago and trying to workaround that
> >>>> usb/scsi detection by simply calling usb reset and scsi reset as the
> >>>> part of PREBOOT. Then all disks are recorded and visible by grub.
> >>>>
> >>>> But I found another issue which is kind of weird. We are using
> >>>> distroboot with soft of fixed sequence. Important part of sequence is
> >>>> sd, usb, scsi.
> >>>>
> >>>> I have added grub on scsi and when I boot directly via run bootcmd_scsi0
> >>>> everything is working fine. When I let distroboot to do the job it or
> >>>> run printenv -e before bootcmd_scsi0 I am getting exception.
> >>>> From debug it is visible that it is exception called from
> >>>> efi_disk_read_blocks.
> >>>>
> >>>>     0  0x7ff5d188 hang()+20: include/bootstage.h, line 389
> >>>>     1  0x7ff5f908 __assert_fail(): lib/panic.c, line 25
> >>>>     2  0x7fe976a8 do_irq(): arch/arm/lib/interrupts_64.c, line 123
> >>>>     3  0x7fe96a0c _restore_regs()+124: arch/arm/cpu/armv8/exceptions.S,
> >>>> line 141
> >>>>     4  0x7ff43740 efi_disk_read_blocks()+160: lib/efi_loader/efi_disk.c,
> >>>> line 102
> >>>
> >>> How and when did you get this stack trace?
> >>
> >> When Abort happened I connected Xilinx debugger via jtag and look at cpu
> >> backtrace.
> > 
> > OK, but we are already in grub here and such a trace (in U-Boot)
> > doesn't make sense. Right?
> 
> Correct grub already started. But I expect it is still using U-Boot
> drivers and all exception handlers are still in place from u-boot.

Yeah, but what I didn't understand was:

!"Synchronous Abort" handler, esr 0x02000000
!elr: ffffffffa816c5b0 lr : 000000000805e218 (reloc)
!elr: 00000000200005b0 lr : 000000007fef2218
(snip)
!Code: 000165fa 0b2d05de 0000ffff 00000000 (20000590)
!UEFI image [0x0000000077d48000:0x0000000077de5fff] '/efi\boot\bootaa64.efi'

"Code:" at the exception doesn't seem to be sane assembler, and
"elr" is not within the code of neither U-Boot nor shim/grub(bootaa64.efi).
("esr" doesn't tell us anything.)
So I wondered where the backtrace came from.

BTW, can you please confirm which function sits at the address of
"lr" (=0x7fe2218)?

> Maybe it is just sata/scsi related issue in EFI but weird is that when
> disks are scan just before command everything is working fine.

What do you mean by "when disks are scanned just before the command"?
The case when you ran "run bootcmd_scsi" without "printenv -e"?

Do you reproduce the problem even if you revert the patch,
"xilinx: zynqmp: Initialize usb and scsi via preboot", and
run the commands, "run scsi_init; [printenv -e;] run bootcmd_scsi?

Can you also try other EFI commands, like "efidebug devices"?

> Should I try to initialize and populate EFI object list all the time?
> (Remove this code for testing)
> 	/* Initialize once only */
> 	if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED)
> 		return efi_obj_list_initialized;

No. EFI subsystem is not implemented in that way.
efi_obj_list_initialized() should be called only once, and
it will be called at the first invocation of any EFI-related commands,
bootefi or printenv -e (or efidebug).

-Takahiro Akashi


> Or based on this thread to try your series pointed above?
> 
> Thanks,
> Michal
>