linux-kernel - Re: [PATCH 2/3 v4] ARM: bcm2835: Add the Raspberry Pi firmware 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]

Message-ID: <55679208.3020509@wwwdotorg.org>
Date:	Thu, 28 May 2015 16:09:12 -0600
From:	Stephen Warren <swarren@...dotorg.org>
To:	Noralf Trønnes <noralf@...nnes.org>,
	Eric Anholt <eric@...olt.net>
CC:	devicetree@...r.kernel.org, linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3 v4] ARM: bcm2835: Add the Raspberry Pi firmware driver

On 05/28/2015 03:39 PM, Noralf Trønnes wrote:
> 
> Den 28.05.2015 23:28, skrev Stephen Warren:
>> On 05/28/2015 12:33 PM, Eric Anholt wrote:
>>> This gives us a function for making mailbox property channel requests
>>> of the firmware, which is most notable in that it will let us get and
>>> set clock rates.
> ...
>>> +int rpi_firmware_property_list(struct device_node *of_node,
>>> +                   void *data, size_t tag_size)
>>> +{
>>> +    struct platform_device *pdev = of_find_device_by_node(of_node);
>> I would expect the of_node -> pdev mapping to happen at client device
>> probe time. Simplest for this driver would be if the
>> client-probe-time-mapping function returned the "struct rpi_firmware"
>> and the client passed that to this function.
> 
> What if the firmware driver/device is removed or reloaded?
> In that case the client has an invalid pointer. It wouldn't know about
> the change.

A provider can't be removed if it has clients. So, you'd have to remove
all clients first, then remove the provider. This may require adding
some code to increment/decrement the module use count when clients look
up the provider and are themselves removed.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/