linux-kernel - Re: [PATCH] Lock 7 is cpuidle specific, use non-generic value for locking

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: <20150313212748.GJ497@linaro.org>
Date:	Fri, 13 Mar 2015 15:27:48 -0600
From:	Lina Iyer <lina.iyer@...aro.org>
To:	Andy Gross <agross@...eaurora.org>
Cc:	Stephen Boyd <sboyd@...eaurora.org>,
	bjorn.andersson@...ymobile.com, linux-arm-msm@...r.kernel.org,
	jhugo@...eaurora.org, linux-kernel@...r.kernel.org, ohad@...ery.com
Subject: Re: [PATCH] Lock 7 is cpuidle specific, use non-generic value for
 locking

On Fri, Mar 13 2015 at 14:02 -0600, Andy Gross wrote:
>On Thu, Mar 12, 2015 at 04:16:00PM -0600, Lina Iyer wrote:
>
><snip>
>
>> >It looks like the remote side unlocks it too? It doesn't seem like this
>> >will work with the framework very well. The framework has a kernel
>> >spinlock attached to the hwspinlock so when we lock the hwspinlock we
>> >also lock the kernel spinlock and we only release the kernel spinlock
>> >when the kernel unlocks the hwspinlock. In this case it seems like
>> >cpuidle wants to have it's own kernel spinlock and just use the trylock
>> >loop part of __hwspin_lock_timeout() without taking any kernel side
>> >locks. Plus it wants to write a specific value to the lock.
>> >
>> Right.
>> Just noticed that part of the hwspinlock. Yes SCM unlocks the
>> hwspinlock. So I cannot hold any lock in Linux. May need changes in the
>> hwspinlock framework. Seems like an additional flag in hwspinlock to not
>> lock any in the trylock path work work. Hmm....
>
>Or a specific EXPORT function for this one usecase which is unlike anyone elses
>usage.

I think, this can be handled well within the QCOM driver. I will submit
a patch for it and we can discuss then later. For now, this will work
fine as is.

Lina

>
>-- 
>Qualcomm Innovation Center, Inc.
>The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>a Linux Foundation Collaborative Project
>
--
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/