linux-kernel - Re: [PATCH] iomm/arm-smmu: Add stall implementation hook

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 for Android: free password hash cracker in your pocket

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

Message-ID: <80a3b07d-f3a7-07c4-4e8f-76e28563027c@arm.com>
Date:   Thu, 7 May 2020 15:56:28 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Rob Clark <robdclark@...il.com>
Cc:     Will Deacon <will@...nel.org>, Joerg Roedel <joro@...tes.org>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH] iomm/arm-smmu: Add stall implementation hook

On 2020-05-07 1:06 pm, Sai Prakash Ranjan wrote:
[...]
> We could have our own context fault handler in QCOM implementation,
> but that would just be duplicating things from arm-smmu context fault
> handler. So I did not think it makes much sense to have our own
> fault handler in qcom impl just for enabling stall model.

Hmm, it's probably worth thinking ahead a bit here, to the "actually 
doing things with stalls" plan. I don't have a clear picture off-hand of 
how well the new device fault handler API might fit into arm-smmu - at 
the very least trying to make it truly generic implies having to play 
nasty tricks with disable_irq() for the general case given the "IRQ may 
remain asserted while SS is active" possibility, and that isn't 
particularly inviting. Not to mention tying it into the 
pretend-auxdomain stuff that *is* rather dependent on the qcom impl. If 
it turns out that you'll eventually have to reimplement the IRQ handler 
anyway for all that, then starting off down that route *might* work out 
cleaner and less hassle overall.

Robin.