From: "Ard Biesheuvel" <ardb@kernel.org>
To: "Borislav Petkov" <bp@alien8.de>
Cc: "Kiryl Shutsemau" <kirill@shutemov.name>,
"Ard Biesheuvel" <ardb+git@google.com>,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
"Vincent Mailhol" <mailhol@kernel.org>,
x86@kernel.org
Subject: Re: [PATCH v2 01/10] x86/boot: Drop pointless re-implementation of panic()
Date: Sun, 13 Sep 2026 18:35:33 +0200 [thread overview]
Message-ID: <862d50e1-2072-407b-882d-5e3074a3c225@app.fastmail.com> (raw)
In-Reply-To: <20260912175410.GAaqWRwnz7bHUtXYSs@fat_crate.local>
On Sat, 12 Sep 2026, at 19:54, Borislav Petkov wrote:
> On Sat, Sep 12, 2026 at 10:41:56AM +0200, Ard Biesheuvel wrote:
>> If you're not taking it as a fix, then yes, please.
>
> Help me understand the exact problem pls:
>
> That panic() function gets called by arch_accept_memory() and *that* gets
> called only by code in drivers/firmware/efi/libstub/unaccepted_memory.c or
> drivers/firmware/efi/unaccepted_memory.c (but that uses the kernel proper
> panic() one).
>
> So we *are* in the context of EFI boot services.
>
> What am I missing?
>
Right, I'd missed that.
But when booting via the EFI stub, the decompressor is omitted entirely,
except for some TDX and SEV-SNP code that is shared between them.
This means calling error() is a bad idea, because the TDX initialization
code that overrides the port I/O based __putstr() handling never executes
in that case.
The reason I want to get rid of panic() is because snprintf() is going
to be removed from the EFI stub.
So I think the current patch is still correct. I will follow up with another
one that moves arch_accept_memory() into the EFI stub, and drops the
dependency on error().
next prev parent reply other threads:[~2026-09-13 16:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 11:55 [PATCH v2 00/10] efi/libstub: Avoid UTF-16 conversion busywork Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 01/10] x86/boot: Drop pointless re-implementation of panic() Ard Biesheuvel
2026-09-09 19:14 ` Borislav Petkov
2026-09-09 20:43 ` Ard Biesheuvel
2026-09-10 13:12 ` Kiryl Shutsemau
2026-09-11 7:32 ` Ard Biesheuvel
2026-09-12 6:10 ` Borislav Petkov
2026-09-12 8:41 ` Ard Biesheuvel
2026-09-12 17:54 ` Borislav Petkov
2026-09-13 16:35 ` Ard Biesheuvel [this message]
2026-09-13 18:11 ` Borislav Petkov
2026-09-09 11:55 ` [PATCH v2 02/10] lib/ucs2_string: Drop arbitrary input size limit and associated WARN() Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 03/10] lib/ucs2_string: Suppress modinfo when __DISABLE_EXPORTS is set Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 04/10] lib/ucs2_string: Split out ucs2_as_utf8_l() taking a separate limit Ard Biesheuvel
2026-09-16 10:26 ` Vincent Mailhol
2026-09-09 11:55 ` [PATCH v2 05/10] efi/libstub: Use ucs2_string library for UTF-16 to UTF-8 conversion Ard Biesheuvel
2026-09-15 17:00 ` Vincent Mailhol
2026-09-09 11:55 ` [PATCH v2 06/10] efi/libstub: Avoid efi_puts() for compile time constant strings Ard Biesheuvel
2026-09-15 17:01 ` Vincent Mailhol
2026-09-09 11:55 ` [PATCH v2 07/10] efi/libstub: Output UTF-16 directly from vsnprintf() Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 08/10] efi/libstub: Add support for printing human readable GUIDs Ard Biesheuvel
2026-09-09 11:55 ` [PATCH v2 09/10] efi/libstub: Add efi_snprintf() to construct wide strings Ard Biesheuvel
2026-09-15 17:02 ` Vincent Mailhol
2026-09-09 11:55 ` [PATCH v2 10/10] efi/libstub: add initial Boot Loader Interface support Ard Biesheuvel
2026-09-15 17:02 ` Vincent Mailhol
2026-09-15 18:28 ` [PATCH v2 00/10] efi/libstub: Avoid UTF-16 conversion busywork Vincent Mailhol
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