On 12/3/23 19:22, Simon Glass wrote:
Hi Heinrich,
On Sun, 3 Dec 2023 at 10:53, Heinrich Schuchardt
<heinrich.schucha...@canonical.com> wrote:
On 12/3/23 18:44, Simon Glass wrote:
Hi Heinrich,
On Sun, 3 Dec 2023 at 03:55, Heinrich Schuchardt
<heinrich.schucha...@canonical.com> wrote:
On 12/3/23 00:38, Shantur Rathore wrote:
Hi Simon,
On Sat, Dec 2, 2023 at 6:33 PM Simon Glass <s...@chromium.org> wrote:
Hi,
On Mon, 20 Nov 2023 at 00:02, Ilias Apalodimas
<ilias.apalodi...@linaro.org> wrote:
Hi Mark,
On Sun, 19 Nov 2023 at 19:38, Mark Kettenis <mark.kette...@xs4all.nl> wrote:
Date: Sat, 18 Nov 2023 23:52:11 +0100
From: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
Hi Heinrich,
On 11/18/23 22:28, Shantur Rathore wrote:
Hi Heinrich,
On Fri, Nov 17, 2023 at 3:12 PM Heinrich Schuchardt
<heinrich.schucha...@canonical.com> wrote:
On 11/16/23 19:45, Shantur Rathore wrote:
On Thu, Nov 16, 2023 at 6:15 PM Heinrich Schuchardt
<heinrich.schucha...@canonical.com> wrote:
On 11/16/23 17:52, Shantur Rathore wrote:
Hi Simon,
Currently bootstd - bootmethod_efi only looks for the default
bootxx64.efi in /EFI/boot folder only.
Generally many distros end up putting their bootloaders in
EFI/<distro> folders like EFI/ubuntu and EFI/debian etc.
In x86 worlds, the NVRAM is modified and new boot entries are added to
support these but in the U-boot world the NVRAM variables are
read-only.
I guess you are referring to UEFI boot options. These typically are not
stored in non-volatile RAM but on a SPI flash device.
Thanks for correcting me.
What would be the best way to implement this?
I was thinking of having a "efi_prefixes" environment variable which
can be set to "ubuntu debian centos" etc and bootmethod_efi can try
all of them. Will bootmethod_efi be able to support multiple entries (
thinking of multiboot ) ?
On my laptop I have:
EFI/Microsoft/Boot/bootmgr.efi
EFI/Microsoft/Boot/memtest.efi
EFI/Boot/bootx64.efi
EFI/Boot/fbx64.efi
EFI/Boot/mmx64.efi
EFI/debian/shimx64.efi
EFI/debian/grubx64.efi
EFI/debian/mmx64.efi
EFI/debian/fbx64.efi
EFI/ubuntu/grubx64.efi
EFI/ubuntu/shimx64.efi
EFI/ubuntu/mmx64.efi
Obviously each installed operating system provides multiple EFI binaries
and non uses the fallback file name BOOT<ARCH>.EFI. A value "ubuntu
debian centos" would not be able to describe which file you are looking
for.
We already have the U-Boot command line eficonfig and efidebug commands
to set up UEFI boot options which can describe which EFI binary to load
and which command line to pass to it. These are considered by the
existing boot flows.
So, I am building a new RockPro64 based cluster and using Canonical
MAAS to set them up automatically, booting them up using DHCP and
installing them over the network.
I configured an Armbian image using Packer to be compatible with MAAS
and it happily installs it. As part of installation process, a
grub-install is run which installs the grub efi,
this EFI ends up in EFI/debian instead of expected EFI/boot.
To be able to make it boot, I have to add commands to move it to
EFI/boot. I am trying to find a way in U-Boot that would allow me to
skip this step.
With eficonfig if I understand correctly, it would need manual
intervention to create boot entries.
If you are installing the shim-signed package on Ubuntu, the EFI boot
option for Ubuntu is set up by EFI/BOOT/BOOT<ARCH>.EFI using the content
of EFI/ubuntu/BOOT<ARCH>.CSV. This is done before ExitBootServices() and
therefore should work with current U-Boot.
Patches are pending upstream to make EFI variables writable from Linux
if they are stored in the RPMB partition in the eMMC. See this series:
https://lore.kernel.org/linux-efi/20231107054057.1893-2-masahisa.koj...@linaro.org/
Would it be possible to save it in SPI Flash as the U-Boot environment ?
Currently this is not supported by U-Boot.
The U-Boot environment variables can be stored in lots of different
places SPI flash is only one of these. But none of these locations is
protected from OS access which would be preferable for UEFI variables
for security reasons.
To support boards without eMMC the right way forward would be writing a
new implementation of the OP-TEE standalone MM which writes the
variables to SPI flash instead of the RPMB partition and ensures that
the SPI flash' MMIO registers are protected against access from the
non-secure world.
Thanks for explaining this to me.
This seems like a long way to go, for now what would be an acceptable
solution, some options are
1. Allow to set a space separated efi_prefixes (e.g. "boot ubuntu
debian") variable which is ready by bootmeth_efi and used as
efi/<efi_prefix> instead of efi/boot.
2. Improve bootmeth_efi to find all bootxxxx.efi in efi/ folder and
present all them as bootflows to bootstd.
As mentioned in a prior mail ubuntu/bootxxxx.efi and debian/bootxxxx.efi
don't exist. I would prefer not to add any distro specific stuff in
upstream U-Boot. Instead we will continue to drive what Linaro has
suggested to improve U-Boot EFI variables support in Linux.
I agree that adding hacks like this is not a good idea.
+ 1
The Linaro approach that involves OP-TEE makes for a fairly complex
solution. And there are plenty of boards that have neither eMMC nor
SPI flash. If Secure Boot is not a requirement (and I'd argue that
for most "hobbyist" boards it isn't) storing the EFI variables in a
file on the ESP (as implemented by the CONFIG_EFI_VARIABLE_FILE_STORE
Kconfig option) is a workable alternative. And this is actually what
the rockpro64-rk3399_defconfig enables.
Even in that case, preseeding the variables can enable uefi secure
boot. But you have to establish a chain of trust since the
authenticated EFI variables are part of the u-boot binary.
I noticed that the latest EBBR attempts to standardize this:
https://arm-software.github.io/ebbr/index.html#document-chapter5-variable-storage
Not sure what the status here is.
Heinrich and I were the ones who proposed the standardization. The
idea is to eventually fix it for all boards and we are working on it,
But if the Linux kernel folks
accept that alternative implementations for runtime EFI variable
access are a thing, then a method that modifies the file would be
possible as well. Or maybe it is good enough to implement support for
this in the efivar library.
Yes to both. I discussed the idea during Linux Plumbers. All
approaches have some pros and cons, you can find some details here
[0].
Implementing support to efitool is straightforward, but a bit too
hacky for my taste. An obvious disadvantage is that it's hard to sync
the kernel/file view after an update.
The plan right now is to investigate overwriting RT functions and use
kernel-provided ones that modify the file (which is probably going to
be passed in a config table)
[0] https://lpc.events/event/17/contributions/1653/
I don't know much about this area, but it strikes me that things are
getting a little too complicated.
U-Boot wants to show a menu of available Operating Systems. With UEFI
it isn't even possible to know what is being booted. We just have to
jump into the .efi file and hope.
Can we work together on adding a new, separate file which lists the
.efi files and what they are for? Then the user can select one.
To add - EFI/BOOT/BOOTXXXX.efi is optional [0] and isn't installed by
generic ARM
distros (debian, armbian.. maybe more)
+1 for this. This can be implemented as part of bootmeth_efi (in blk
mode) where instead
of checking hardcoded EFI/BOOT/BOOTXXXX.efi, it can follow one of the
following options
1. Scan and list all available .efi files - EFI/**/*.efi
Pros - Allows all the possible boot options to be shown to user
Cons - A 'bootflow scan -b' might not boot the system by default as it
might depend on
which efi file is scanned first. Some installs have mmaa64.efi
2. Scan and list all available .efi files that match the
"bootmeth_efi_regex" variable if available.
This variable can be configured to allow valid names example
"EFI\/.*\/(boot|grub|fb|shim).*efi"
Pros - Allows to control only efi files that can boot the system by default.
Cons - Might be an issue in environments without CONFIG_REGEX
3. Scan all the folders EFI/* for EFI file prefixes controlled by
"bootmeth_efi_name_prefixes" variable
This variable can be a space separated list of all valid prefixes the
user is interested in. e.g. "boot grub fb shim"
Pros - This allows control on what EFI files to look for without being
depended on CONFIG_REGEX
Cons - I can't think of, please do tell.
After this, bootmeth_efi can set up more than 1 bootflows that are bootable.
[0] - https://www.rodsbooks.com/efi-bootloaders/principles.html
Kind regards,
Shantur
U-Boot should remain be a compliant UEFI implementation. We shall not
scan any other directories than those described in the UEFI specification.
For the efi bootmeth we can actually do what we like, can't we? Its
behaviour isn't defined by the spec as I understand it.
I wonder how this works, if the user installs both Debian and Ubuntu
on the machine? I suppose each one separately updates its grub.cfg
with all the OSes it can find on the machine? Then just one of them
gets to be the initial .efi app?
Can we work together on adding a new, separate file which lists the
.efi files and what they are for?
There is already a place defined by the UEFI specification where to put
that information: the UEFI boot options defined in variables BOOT####.
And this is exactly what all operating system use. The information what
the entries are for are in the label part of the boot options. The
sequence in which to try loading is in variable BootOrder.
There is no point in reinventing the wheel and making it square.
You have not addressed my question, or I don't understand your answer.
I am not worried about what the computer does. I am worried about what
the user sees.
So far as I can tell there is currently no way to know what you are
booting (Ubuntu, Debian) until you boot it
Of course I know. These are some of the boot options on my laptop:
Boot0000* Windows Boot Manager
HD(2,GPT,54e58a37-c1db-4c6b-afda-24340c39cda5,0x109000,0x32000)/File(\EFI\Microsoft\Boot\bootmgfw.efi)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.5.3.7.2.}...M................
Boot0001* debian
HD(2,GPT,54e58a14-c1db-4c6b-afda-24340c39cda5,0x109000,0x32000)/File(\EFI\debian\shimx64.efi)
Boot0002* ubuntu
HD(2,GPT,54e58a14-c1db-4c6b-afda-24340c39cda5,0x109000,0x32000)/File(\EFI\ubuntu\shimx64.efi)
Boot0063* EFI Shell
HD(2,GPT,54e58a14-c1db-4c6b-afda-24340c39cda5,0x109000,0x32000)/File(Shell.efi)
If I open the boot menu (F12 key on a Lenovo laptop, F8 key on an ASUS
mainboards), I see a menu which allows me to choose which of Windows,
Debian, Ubuntu, or the EFI Shell I want to boot.
In U-Boot we already have the same. Please, have a look at the section
'UEFI boot variable enumeration' in doc/usage/cmd/bootmenu.rst.
Best regards
Heinrich
