linux-kernel - Re: [PATCH v1] clk: Mark a fwnode as initialized when using CLK_OF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 1 Mar 2023 13:25:13 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Stephen Boyd <sboyd@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Michael Turquette <mturquette@...libre.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        kernel-team@...roid.com, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] clk: Mark a fwnode as initialized when using
 CLK_OF_DECLARE* macros

On Wed, Mar 1, 2023 at 12:48 PM Stephen Boyd <sboyd@...nel.org> wrote:
>
> Quoting Stephen Boyd (2023-03-01 12:40:03)
> > Quoting Saravana Kannan (2023-02-28 17:25:06)
> > > The CLK_OF_DECLARE macros sometimes prevent the creation of struct
> > > devices for the device node being handled. It does this by
> > > setting/clearing OF_POPULATED flag. This can block the probing of some
> > > devices because fw_devlink will block the consumers of this node till a
> > > struct device is created and probed.
> >
> > Why can't you use CLK_OF_DECLARE_DRIVER()?
>
> Ah I misunderstood. CLK_OF_DECLARE() _always_ prevents the creation of a
> struct device for the device node being handled. The 'sometimes' threw
> me off.

The "sometimes" is because dependending on the macro we go back and
clear the flag.

> >
> > >
> > > Set the appropriate fwnode flags when these device nodes are initialized
> > > by the clock framework and when OF_POPULATED flag is set/cleared. This
> > > will allow fw_devlink to handle the dependencies correctly.
>
> How is this different from commit 3c9ea42802a1 ("clk: Mark fwnodes when
> their clock provider is added/removed")? Do you have some user of
> CLK_OF_DECLARE() that isn't registering an OF clk provider?

So it looks like drivers don't always register the same node used for
CLK_OF_DECLARE() as the clock provider. So, this is covering for the
case when that's not true.

-Saravana