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From: Shawn Guo <shawn.guo@linaro.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v3 2/2] arm64/acpi: disallow writeable AML opregion mapping for EFI code regions
Date: Sat, 6 Feb 2021 18:45:15 +0800	[thread overview]
Message-ID: <20210206104514.GB27503@dragon> (raw)
In-Reply-To: <CAMj1kXHSkBcSDuHbsFMJjC89JrO8TxYUoabDmWerNp27s45Ngw@mail.gmail.com>

On Sat, Feb 06, 2021 at 09:10:19AM +0100, Ard Biesheuvel wrote:
> On Sat, 6 Feb 2021 at 04:11, Shawn Guo <shawn.guo@linaro.org> wrote:
> >
> > Hi Ard,
> >
> > On Fri, Jun 26, 2020 at 05:58:32PM +0200, Ard Biesheuvel wrote:
> > > Given that the contents of EFI runtime code and data regions are
> > > provided by the firmware, as well as the DSDT, it is not unimaginable
> > > that AML code exists today that accesses EFI runtime code regions using
> > > a SystemMemory OpRegion. There is nothing fundamentally wrong with that,
> > > but since we take great care to ensure that executable code is never
> > > mapped writeable and executable at the same time, we should not permit
> > > AML to create writable mapping.
> > >
> > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> >
> > I'm booting Lenovo Flex 5G laptop with ACPI, and seeing this change
> > causes a memory abort[1] when upgrading ACPI tables via initrd[2].
> > Dropping this change seems to fix the issue for me.  But does that
> > looks like a correct fix to you?
> >
> > Shawn
> >
> > [1] https://fileserver.linaro.org/s/iDe9SaZeNNkyNxG
> > [2] Documentation/admin-guide/acpi/initrd_table_override.rst
> >
> 
> Can you check whether reverting
> 
> 32cf1a12cad43358e47dac8014379c2f33dfbed4
> 
> fixes the issue too?

Yes, it does.

> If it does, please report this as a regression. The OS should not
> modify firmware provided tables in-place, regardless of how they were
> delivered.
> 
> BTW I recently started using my Yoga C630 with Debian, and I am quite
> happy with it! Thanks a lot for spending the time on the installer
> etc.

Cool, glad to hear that!

Shawn

  parent reply	other threads:[~2021-02-06 10:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-26 15:58 [PATCH v3 0/2] arm64/acpi: restrict AML opregion memory access Ard Biesheuvel
2020-06-26 15:58 ` [PATCH v3 1/2] arm64/acpi: disallow AML memory opregions to access kernel memory Ard Biesheuvel
2020-09-28 16:02   ` Jonathan Cameron
2020-09-28 16:49     ` Ard Biesheuvel
2020-09-28 17:17       ` Jonathan Cameron
2020-09-29  9:29         ` Ard Biesheuvel
2020-09-30  9:27           ` Jonathan Cameron
2020-09-30 17:19             ` Catalin Marinas
2020-06-26 15:58 ` [PATCH v3 2/2] arm64/acpi: disallow writeable AML opregion mapping for EFI code regions Ard Biesheuvel
2021-02-06  3:11   ` Shawn Guo
2021-02-06  8:10     ` Ard Biesheuvel
2021-02-06 10:17       ` Ard Biesheuvel
2021-02-06 10:45       ` Shawn Guo [this message]
2020-07-08 16:17 ` [PATCH v3 0/2] arm64/acpi: restrict AML opregion memory access Ard Biesheuvel
2020-07-09  8:42 ` Lorenzo Pieralisi
2020-07-14 19:52 ` Catalin Marinas

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