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From: Clayton Craft <clayton@craftyguy.net>
To: linux-efi@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>
Cc: clayton@craftyguy.net
Subject: x86_64 32-bit EFI mixed mode boot broken
Date: Thu, 21 Mar 2024 14:45:41 -0700	[thread overview]
Message-ID: <20240321144541.GD8211@craftyguy.net> (raw)

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I've been chasing a problem with 32-bit EFI mixed mode booting on two different
(x86_64) Intel Bay Trail platforms, where the system reboots or hangs seemingly
very early somewhere before or after loading the kernel. I've not been able to
get any output from the kernel or stub over efifb when the issue happens[0], and
do not have serial console access on these systems. 

v6.8 fails for me, and presumably so does everything back to v6.2. v6.1 is able
to boot OK on these platforms with mixed mode, and it looks like there are a lot
of changes from 6.1..6.2 for EFI/mixed mode booting. I did managed to bisect the
issue to: 

        commit e2ab9eab324cdf240de89741e4a1aa79919f0196
        Author: Ard Biesheuvel <ardb@kernel.org>
        Date:   Tue Nov 22 17:10:02 2022 +0100
        
            x86/boot/compressed: Move 32-bit entrypoint code into .text section

However I'm not sure how to proceed from here, or if my bisect is all that
useful since the commit seems to be in the middle of a bunch of changes I do not
understand. I've been using systemd-boot to test this (both the full bootloader
and UKI w/ the sd-boot stub). Is 32-bit mixed mode on x86_64 working for others?

Thanks,
Clayton

0. Using "debug ignore_loglevel earlycon=efifb earlyprintk=efi,keep efi=debug"

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             reply	other threads:[~2024-03-21 21:45 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-21 21:45 Clayton Craft [this message]
  -- strict thread matches above, loose matches on Subject: below --
2024-03-21 22:05 x86_64 32-bit EFI mixed mode boot broken Clayton Craft
2024-03-21 22:48 ` Ard Biesheuvel
2024-03-22  0:06   ` Clayton Craft
2024-03-22 12:52     ` Ard Biesheuvel
2024-03-22 16:18       ` Clayton Craft
2024-03-22 16:51         ` Ard Biesheuvel
2024-03-22 17:57           ` Clayton Craft
2024-03-22 18:30             ` Ard Biesheuvel
2024-03-22 19:34               ` Clayton Craft
2024-03-23 12:39                 ` Ard Biesheuvel
2024-03-23 17:18                   ` Ard Biesheuvel
2024-03-24  5:53                     ` Clayton Craft
2024-03-24 14:49   ` Hans de Goede
2024-03-24 17:43     ` Ard Biesheuvel
2024-03-24 20:45       ` Clayton Craft
2024-03-24 20:53         ` Ard Biesheuvel
2024-04-01 22:44           ` Clayton Craft
2024-04-02  6:25             ` Ard Biesheuvel

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