From: Ard Biesheuvel <ardb@kernel.org>
To: Dave Young <dyoung@redhat.com>,
pjones@redhat.com, daniel.kiper@oracle.com,
Leif Lindholm <leif@nuviainc.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
Borislav Petkov <bp@alien8.de>, Sergey Shatunov <me@prok.pw>,
hpa@zytor.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
mingo@redhat.com, Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, linux-efi <linux-efi@vger.kernel.org>,
initramfs@vger.kernel.org,
Donovan Tremura <neurognostic@protonmail.ch>,
Harald Hoyer <harald@hoyer.xyz>
Subject: Re: [PATCH 1/2] efi/x86: Move efi stub globals from .bss to .data
Date: Wed, 8 Apr 2020 09:49:15 +0200 [thread overview]
Message-ID: <CAMj1kXGPOZ6zWtgGScLy0ECrTtf1yhngDTNE1chW-MQw3XQp9Q@mail.gmail.com> (raw)
In-Reply-To: <20200408074334.GA21886@dhcp-128-65.nay.redhat.com>
(add Peter, Leif and Daniel)
On Wed, 8 Apr 2020 at 09:43, Dave Young <dyoung@redhat.com> wrote:
>
> On 04/06/20 at 02:06pm, Arvind Sankar wrote:
> > Commit
> >
> > 3ee372ccce4d ("x86/boot/compressed/64: Remove .bss/.pgtable from
> > bzImage")
> >
> > removed the .bss section from the bzImage.
> >
> > However, while a PE loader is required to zero-initialize the .bss
> > section before calling the PE entry point, the EFI handover protocol
> > does not currently document any requirement that .bss be initialized by
> > the bootloader prior to calling the handover entry.
> >
> > When systemd-boot is used to boot a unified kernel image [1], the image
> > is constructed by embedding the bzImage as a .linux section in a PE
> > executable that contains a small stub loader from systemd together with
> > additional sections and potentially an initrd. As the .bss section
> > within the bzImage is no longer explicitly present as part of the file,
> > it is not initialized before calling the EFI handover entry.
> > Furthermore, as the size of the embedded .linux section is only the size
> > of the bzImage file itself, the .bss section's memory may not even have
> > been allocated.
>
> I did not follow up the old report, maybe I missed something. But not
> sure why only systemd-boot is mentioned here. I also have similar issue
> with early efi failure. With these two patches applied, it works well
> then.
>
> BTW, I use Fedora 31 + Grub2
>
OK, so I take it this means that GRUB's PE/COFF loader does not
zero-initialize BSS either? Does it honor the image size in memory if
it exceeds the file size?
next prev parent reply other threads:[~2020-04-08 7:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200109150218.16544-1-nivedita@alum.mit.edu>
[not found] ` <20200405154245.11972-1-me@prok.pw>
2020-04-05 23:18 ` [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage Arvind Sankar
2020-04-06 0:00 ` Sergey Shatunov
2020-04-06 3:51 ` Arvind Sankar
2020-04-06 7:32 ` Ard Biesheuvel
2020-04-06 8:47 ` Borislav Petkov
2020-04-06 9:11 ` Ard Biesheuvel
2020-04-06 11:20 ` Borislav Petkov
2020-04-06 13:22 ` Arvind Sankar
2020-04-06 13:29 ` Ard Biesheuvel
2020-04-06 16:01 ` Arvind Sankar
2020-04-06 16:22 ` Ard Biesheuvel
2020-04-06 16:52 ` Arvind Sankar
2020-04-06 16:59 ` Ard Biesheuvel
2020-04-06 18:06 ` [PATCH 1/2] efi/x86: Move efi stub globals from .bss to .data Arvind Sankar
2020-04-06 18:06 ` [PATCH 2/2] efi/x86: Always relocate the kernel for EFI handover entry Arvind Sankar
2020-04-06 18:29 ` [PATCH 1/2] efi/x86: Move efi stub globals from .bss to .data Ard Biesheuvel
2020-04-08 7:43 ` Dave Young
2020-04-08 7:49 ` Ard Biesheuvel [this message]
2020-04-09 14:39 ` Arvind Sankar
2020-04-09 14:47 ` Ard Biesheuvel
2020-04-09 16:35 ` Arvind Sankar
2020-04-10 14:47 ` Arvind Sankar
2020-04-10 15:26 ` Ard Biesheuvel
2020-04-14 14:57 ` Daniel Kiper
2020-04-10 11:26 ` Thomas Meyer
2020-04-10 14:38 ` Arvind Sankar
2020-04-11 8:50 ` Thomas Meyer
2020-04-06 17:21 ` [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage Borislav Petkov
2020-04-06 8:44 ` Ard Biesheuvel
2020-04-06 12:36 ` Sergey Shatunov
2020-04-06 13:20 ` Ard Biesheuvel
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