linux-kernel - RE: [PATCH v4 1/8] drivers: base: Add hardware prefetch control core driver

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, 18 May 2022 12:38:02 +0000
From:   "tarumizu.kohei@...itsu.com" <tarumizu.kohei@...itsu.com>
To:     'Greg KH' <gregkh@...uxfoundation.org>
CC:     "catalin.marinas@....com" <catalin.marinas@....com>,
        "will@...nel.org" <will@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
        "rafael@...nel.org" <rafael@...nel.org>,
        "mchehab+huawei@...nel.org" <mchehab+huawei@...nel.org>,
        "eugenis@...gle.com" <eugenis@...gle.com>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "pcc@...gle.com" <pcc@...gle.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "marcos@...a.pet" <marcos@...a.pet>,
        "conor.dooley@...rochip.com" <conor.dooley@...rochip.com>,
        "nicolas.ferre@...rochip.com" <nicolas.ferre@...rochip.com>,
        "marcan@...can.st" <marcan@...can.st>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "arnd@...db.de" <arnd@...db.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH v4 1/8] drivers: base: Add hardware prefetch control core
 driver

Thanks for the comment.

> This feels wrong, attributes should be groups and be automatically added and
> removed by the driver core that way.  Not as lists of attributes like this, as that
> will race and be wrong.
> 
> Use a list of attribute groups please.

> You just raced with userspace and lost :(
> 
> Please use attribute groups instead of manually adding files after the device is
> created and userspace is notified that it was present.
> 
> That also makes your clean up logic much simpler (i.e. none as the drive core did it
> for you already.)

> Attribute groups please.

I modify to use attribute groups in the next version.

> Why do you think this needs to be in the driver core?  Why isn't this just a normal
> cpu driver?
> 
> thanks,

Does this mean that creating only dedicated driver for a CPU (e.g.
arch/x86/kernel/cpu/x86-pfctl.c) without creating core driver?
If so, there is no problem. I remove the core driver and create only
the dedicated drivers for each CPU in the next version.

As a reference, I previously wanted to define it as a common sysfs I/F
for A64FX and x86, so I create a core driver to provide it. However,
as I proceed with the consideration, it became clear that these were
independent I/F specifications. Therefore, the core driver is not
currently needed.