Re: [PATCH v1 3/3] partitions/efi: Support gpt_sector parameter needed by NVIDIA Tegra devices

29.03.2021 09:18, Christoph Hellwig пишет:

On Sun, Mar 28, 2021 at 12:21:00AM +0300, Dmitry Osipenko wrote:

quoted

All NVIDIA Tegra20..124 Android devices use proprietary bootloader
which supplies the gpt_sector=<sector> kernel cmdline parameter that
should be used for looking up the EFI partition table on internal EMMC
storage.  If the kernel cmdline parameter isn't supplied, then the
partition is expected to be placed around the last but one sector of EMMC.

Apparently this was done in order to hide the PT from a usual userspace
tools since EFI entry exists only for compatibility with a Linux kernel,

That's weird, because nothin in Linux relies in EFI partition tables.

quoted

while a custom proprietary partition table is what is really used by
these Android devices, thus these tools may corrupt the real PT, making
device unbootable and very difficult to restore.

Add support for the gpt_sector cmdline parameter which will be used
for finding EFI entry on internal EMMC storage of NVIDIA Tegra20+ devices.

Didn't we plan to just support the actual partition table format insted?

Ideally we need to support both forced-gpt and tegra-partition.  At
first we should check whether GPT entry exists and use it on success,
otherwise fall back to tegra-partition.  This will allow to properly
support all kind of devices.  The majority of devices have the GPT
entry, so will be good to support it at least.

My understanding that this all require involvement from Jens Axboe in
order to get the patches merged.  Previously he didn't show interest to
any of the patches and my assumption was that he didn't want to have
another partition, although I don't know for sure because he never answered.

If you could help with reviewing and applying of the patches, then I
will be happy to try again with re-sending a full patchset, which
includes the tegra-partition support.