Re: [PATCH v6 07/13] arm64: add basic pointer authentication support

From: Pavel Machek <pavel@ucw.cz>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kristina Martsenko <kristina.martsenko@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Adam Wallis <awallis@codeaurora.org>,
	Amit Kachhap <amit.kachhap@arm.com>,
	Andrew Jones <drjones@redhat.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Dave P Martin <dave.martin@arm.com>,
	Jacob Bramley <jacob.bramley@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 07/13] arm64: add basic pointer authentication support
Date: Fri, 4 Jan 2019 10:33:40 +0100	[thread overview]
Message-ID: <20190104093340.GA28150@amd> (raw)
In-Reply-To: <681a2835-1a70-f3c3-3534-7b4cf6139cac@arm.com>

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On Fri 2019-01-04 09:21:30, Marc Zyngier wrote:
> On 03/01/2019 20:29, Pavel Machek wrote:
> > On Fri 2018-12-07 18:39:25, Kristina Martsenko wrote:
> >> From: Mark Rutland <mark.rutland@arm.com>
> >> 
> >> This patch adds basic support for pointer authentication,
> >> allowing userspace to make use of APIAKey, APIBKey, APDAKey,
> >> APDBKey, and APGAKey. The kernel maintains key values for each
> >> process (shared by all threads within), which are initialised to
> >> random values at exec()
> > time.
> > 
> > ...
> > 
> >> +/* + * We give each process its own keys, which are shared by
> >> all threads. The keys + * are inherited upon fork(), and
> >> reinitialised upon exec*(). + */ +struct ptrauth_keys { +	struct
> >> ptrauth_key apia; +	struct ptrauth_key apib; +	struct ptrauth_key
> >> apda; +	struct ptrauth_key apdb; +	struct ptrauth_key apga; +};
> > 
> > intstruction_a, data_a, generic_a? Should be easier to understand
> > than "apdb" ...
> 
> ... until you realize that these names do match the documentation,
> which makes it even easier to understand how the code uses the
> architecture.

See how not even the commit log matches the documentation then?

Naming something "apdb" is just bad... Just because the documentation
is evil does not mean it should be followed...

								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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