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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-efi@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 12/17] efi: fix efi_pci_io_protocol32 prototype for mixed mode
Date: Mon, 14 May 2018 09:02:34 +0200	[thread overview]
Message-ID: <CAKv+Gu8QVR_BFLMKttqfmCMqXU13grwr846oftFysB8B0CJCZw@mail.gmail.com> (raw)
In-Reply-To: <20180514065744.GD16596@gmail.com>

On 14 May 2018 at 08:57, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
>> Mixed mode allows a kernel built for x86_64 to interact with 32-bit
>> EFI firmware, but requires us to define all struct definitions carefully
>> when it comes to pointer sizes. efi_pci_io_protocol32 currently uses a
>> void* for the 'romimage' field, which will be interpreted as a 64-bit
>> field on such kernels, potentially resulting in bogus memory references
>> and subsequent crashes.
>
> Yeah, so the first confusion I ran into is:
>
>  s/efi_pci_io_protocol32
>   /efi_pci_io_protocol_32
>
> Once I found it in the code I made this change:
>
>  s/efi: fix efi_pci_io_protocol32 prototype for mixed mode
>   /efi: Fix 'struct efi_pci_io_protocol32' definition for mixed mode
>
> Because we normally use the 'prototype' name for function declarations, not for
> data type definitions. Adding 'struct' and putting it between quotes makes it
> obvious at a glance that we are talking about a structure definition here.
>

OK.

> BTW., since it's marked -stable, due to:
>
>  > potentially resulting in bogus memory references
>  > and subsequent crashes.
>
> I'm moving it to efi/urgent: the principle here is that if a patch is urgent
> enough for -stable then it should generally not wait for the next merge window.
>

The issue was found by inspection rather than a crash report, so I was
in doubt about this.

> Also, because this actually fixes a crash, I extended the title to spell this out
> more clearly:
>
>   Subject: efi: Avoid potential crashes, fix the 'struct efi_pci_io_protocol_32' definition for mixed mode
>
> ... which also makes it easier for maintainers of older stable kernels to decide
> whether to backport the patch or not.
>

OK.

> Anyway, the patch is looking good otherwise, no need to resend.
>
> Thanks,
>
>         Ingo

  reply	other threads:[~2018-05-14  7:02 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-04  5:59 [GIT PULL 00/17] EFI updates for v4.18 Ard Biesheuvel
2018-05-04  5:59 ` [PATCH 01/17] x86/xen/efi: Initialize UEFI secure boot state during dom0 boot Ard Biesheuvel
2018-05-14  7:43   ` [tip:efi/core] " tip-bot for Daniel Kiper
2018-05-04  5:59 ` [PATCH 02/17] efi/cper: Remove the INDENT_SP silliness Ard Biesheuvel
2018-05-14  7:44   ` [tip:efi/core] " tip-bot for Borislav Petkov
2018-05-04  5:59 ` [PATCH 03/17] efi: Fix IA32/X64 Processor Error Record definition Ard Biesheuvel
2018-05-14  7:44   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 04/17] efi: Decode IA32/X64 Processor Error Section Ard Biesheuvel
2018-05-14  7:45   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 05/17] efi: Decode IA32/X64 Processor Error Info Structure Ard Biesheuvel
2018-05-14  7:45   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 06/17] efi: Decode UEFI-defined IA32/X64 Error Structure GUIDs Ard Biesheuvel
2018-05-14  7:46   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 07/17] efi: Decode IA32/X64 Cache, TLB, and Bus Check structures Ard Biesheuvel
2018-05-14  7:46   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 08/17] efi: Decode additional IA32/X64 Bus Check fields Ard Biesheuvel
2018-05-14  7:47   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 09/17] efi: Decode IA32/X64 MS Check structure Ard Biesheuvel
2018-05-14  7:47   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 10/17] efi: Decode IA32/X64 Context Info structure Ard Biesheuvel
2018-05-14  7:48   ` [tip:efi/core] " tip-bot for Yazen Ghannam
2018-05-04  5:59 ` [PATCH 11/17] efi/libstub/tpm: Make function efi_retrieve_tpm2_eventlog_1_2() static Ard Biesheuvel
2018-05-14  7:48   ` [tip:efi/core] " tip-bot for Wei Yongjun
2018-05-04  5:59 ` [PATCH 12/17] efi: fix efi_pci_io_protocol32 prototype for mixed mode Ard Biesheuvel
2018-05-14  6:57   ` Ingo Molnar
2018-05-14  7:02     ` Ard Biesheuvel [this message]
2018-05-14  7:42   ` [tip:efi/core] efi: Avoid potential crashes, fix the 'struct efi_pci_io_protocol_32' definition " tip-bot for Ard Biesheuvel
2018-05-04  5:59 ` [PATCH 13/17] efi: align efi_pci_io_protocol typedefs to type naming convention Ard Biesheuvel
2018-05-14  7:49   ` [tip:efi/core] efi: Align " tip-bot for Ard Biesheuvel
2018-05-04  6:00 ` [PATCH 14/17] efi/x86: fold __setup_efi_pci32 and __setup_efi_pci64 into one Ard Biesheuvel
2018-05-14  7:49   ` [tip:efi/core] efi/x86: Fold __setup_efi_pci32() and __setup_efi_pci64() into one function tip-bot for Ard Biesheuvel
2018-05-04  6:00 ` [PATCH 15/17] efi/x86: Ignore unrealistically large option roms Ard Biesheuvel
2018-05-14  6:40   ` Ingo Molnar
2018-05-14  6:43   ` [PATCH] efi/x86: Clean up the eboot code a bit Ingo Molnar
2018-05-14  6:47     ` Ard Biesheuvel
2018-05-14  6:58       ` Ingo Molnar
2018-05-14  6:59         ` Ard Biesheuvel
2018-05-14  7:50   ` [tip:efi/core] efi/x86: Ignore unrealistically large option ROMs tip-bot for Hans de Goede
2018-05-15  9:18     ` Ard Biesheuvel
2018-06-21 15:13       ` Ingo Molnar
2018-05-04  6:00 ` [PATCH 16/17] efi/capsule-loader: Don't output reset log when reset flags are not set Ard Biesheuvel
2018-05-14  7:50   ` [tip:efi/core] " tip-bot for Shunyong Yang
2018-05-04  6:00 ` [PATCH 17/17] efi/libstub/arm64: handle randomized TEXT_OFFSET Ard Biesheuvel
2018-05-14  6:47   ` Ingo Molnar
2018-05-14  6:48     ` Ard Biesheuvel
2018-05-14  7:00       ` Ingo Molnar
2018-05-14  7:01         ` Ard Biesheuvel

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