From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Kees Cook <keescook@chromium.org>
Cc: Bhumika Goyal <bhumirks@gmail.com>,
Julia Lawall <julia.lawall@lip6.fr>,
Jason Cooper <jason@lakedaemon.net>,
andrew@lunn.ch, gregory.clement@free-electrons.com,
sebastian.hesselbarth@gmail.com, a.zummo@towertech.it,
alexandre.belloni@free-electrons.com,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
rtc-linux@googlegroups.com, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] rtc: armada38x: add __ro_after_init to armada38x_rtc_ops
Date: Tue, 3 Jan 2017 21:31:18 +0000 [thread overview]
Message-ID: <20170103213118.GM14217@n2100.armlinux.org.uk> (raw)
In-Reply-To: <CAGXu5jJLA=GcOhV5Z_6AOGa1KhW7fXtqBGrewEeViaJ9TiE-aw@mail.gmail.com>
On Tue, Jan 03, 2017 at 01:18:29PM -0800, Kees Cook wrote:
> On Mon, Jan 2, 2017 at 6:06 AM, Russell King - ARM Linux
> <linux@armlinux.org.uk> wrote:
> > On Mon, Dec 26, 2016 at 05:01:02PM +0530, Bhumika Goyal wrote:
> >> The object armada38x_rtc_ops of type rtc_class_ops structure is not
> >> modified after getting initialized by armada38x_rtc_probe. Apart from
> >> getting referenced in init it is also passed as an argument to the function
> >> devm_rtc_device_register but this argument is of type const struct
> >> rtc_class_ops *. Therefore add __ro_after_init to its declaration.
> >
> > What I'd prefer here is for the structure to be duplicated, with one
> > copy having the alarm methods and one which does not. Both can then
> > be made "const" (so placed into the read-only section at link time)
> > and the probe function select between the two.
> >
> > I think that's a cleaner and better solution, even though it's
> > slightly larger.
> >
> > I'm not a fan of __ro_after_init being used where other solutions are
> > possible.
>
> Can the pointer that points to the struct rtc_class_ops be made ro_after_init?
It's passed into the RTC core code, and probably stored in some dynamically
allocated object, so probably no. It's the same class of problem as every
file_operations pointer in the kernel, or the thousand other operations
structure pointers that a running kernel has.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2017-01-03 21:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-26 11:31 [PATCH] rtc: armada38x: add __ro_after_init to armada38x_rtc_ops Bhumika Goyal
2017-01-02 14:06 ` Russell King - ARM Linux
2017-01-03 21:18 ` Kees Cook
2017-01-03 21:31 ` Russell King - ARM Linux [this message]
2017-01-03 21:54 ` Russell King - ARM Linux
2017-01-04 10:57 ` Julia Lawall
2017-01-04 11:07 ` Alexandre Belloni
2017-01-04 11:43 ` Julia Lawall
2017-01-04 12:14 ` Russell King - ARM Linux
2017-01-04 12:23 ` Julia Lawall
2017-01-04 13:06 ` Russell King - ARM Linux
2017-01-04 13:41 ` Julia Lawall
2017-01-04 21:53 ` Kees Cook
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