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From: Ingo Molnar <mingo@kernel.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	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 08:57:44 +0200	[thread overview]
Message-ID: <20180514065744.GD16596@gmail.com> (raw)
In-Reply-To: <20180504060003.19618-13-ard.biesheuvel@linaro.org>


* 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.

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.

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.

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

Thanks,

	Ingo

  reply	other threads:[~2018-05-14  7:14 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 [this message]
2018-05-14  7:02     ` Ard Biesheuvel
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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