From: Will Deacon <will@kernel.org>
To: Steve Capper <steve.capper@arm.com>
Cc: mark.rutland@arm.com, catalin.marinas@arm.com,
jeremy.linton@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: Introduce sysctl to disable pointer authentication
Date: Wed, 8 Jul 2020 08:36:21 +0100 [thread overview]
Message-ID: <20200708073621.GA25261@willie-the-truck> (raw)
In-Reply-To: <20200707173232.5535-1-steve.capper@arm.com>
On Tue, Jul 07, 2020 at 06:32:32PM +0100, Steve Capper wrote:
> Pointer authentication is a mandatory feature in the Armv8.3
> architecture that provides protection against return oriented
> programming attacks. (meaning that all Arm CPUs targetting at least
> Armv8.3 will have this feature).
>
> Once CONFIG_ARM64_PTR_AUTH=y, any systems with the hardware support for
> pointer authentication will automatically have it enabled by the kernel.
>
> There are, however, situations where end users may want to disable
> pointer authentication. One could be tracking down/working around a bug
> in userspace relating to pointer auth. Also, one may wish to quantify
> the performance overhead of pointer auth by running a workload
> with/without it.
If you're debugging userspace, just recompile your userspace application
without ptr auth, in the same way that you might recompile with -g.
The performance argument sucks; this stuff needs to be fast otherwise it's
pointless. If you really need that last bit of speed, try Gentoo ;)
Will
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next prev parent reply other threads:[~2020-07-08 7:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 17:32 [PATCH] arm64: Introduce sysctl to disable pointer authentication Steve Capper
2020-07-08 7:36 ` Will Deacon [this message]
2020-07-08 13:46 ` Steve Capper
2020-07-08 22:08 ` Will Deacon
2020-07-09 14:34 ` Jeremy Linton
2020-07-14 17:52 ` Catalin Marinas
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