linux-kernel - Re: [PATCH V2 1/2] firmware: arm_scmi: Ensure that the message-id supports fastchannel

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: <31655ff6-a020-6f4e-0851-cfa8d0d45803@quicinc.com>
Date: Mon, 7 Oct 2024 12:16:39 +0530
From: Sibi Sankar <quic_sibis@...cinc.com>
To: Konrad Dybcio <konradybcio@...nel.org>,
        Cristian Marussi
	<cristian.marussi@....com>,
        Sudeep Holla <sudeep.holla@....com>
CC: Johan Hovold <johan@...nel.org>, <linux-kernel@...r.kernel.org>,
        <arm-scmi@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH V2 1/2] firmware: arm_scmi: Ensure that the message-id
 supports fastchannel



On 9/5/24 18:24, Konrad Dybcio wrote:
> On 4.09.2024 4:20 PM, Cristian Marussi wrote:
>> On Wed, Sep 04, 2024 at 01:38:55PM +0100, Sudeep Holla wrote:
>>> On Wed, Sep 04, 2024 at 01:29:29PM +0200, Konrad Dybcio wrote:
>>>> On 4.09.2024 9:00 AM, Johan Hovold wrote:
>>>
>>> [...]
>>>
>>>>>
>>>>> Unfortunately, this patch breaks resume from suspend on the x1e80100 crd:
>>>>>
>>>>>          [   26.919676] CPU4: Booted secondary processor 0x0000010000 [0x511f0011]
>>>>>          [   26.960607] arm-scmi firmware:scmi: timed out in resp(caller: do_xfer+0x164/0x568)
>>>>>          [   26.987142] cpufreq: cpufreq_online: ->get() failed
>>>>>
>>>>> and then the machine hangs (mostly, I saw an nvme timeout message after a
>>>>> while).
>>>>>
>>>>> Make sure you test suspend as well as some of the warnings I reported
>>>>> only show up during suspend.
>>>>
>>>> Eh it looks like PERF_LEVEL_GET (msgid 8) requires the use of FC, but
>>>> the firmware fails to inform us about it through BIT(0) in attrs..
>>>>
>>>
>>> Just trying to understand things better here. So the firmware expects OSPM
>>> to just use FC only for PERF_LEVEL_GET and hence doesn't implement the
>>> default/normal channel for PERF_LEVEL_GET(I assume it returns error ?)
>>> but fails to set the attribute indicating FC is available for the domain.
>>>
>>
>> Is not that FCs are optional BUT PERF_LEVEL_GET standard messages is
>> support is mandatory by the spec anyway ?
> 
> So doing a bit of poking I think it's that FC is not marked as supported,
> but we need to read out the frequency from the .get_addr.. which is only
> populated if we go through fastchannel_init

On further debug it was found that the SCP was servicing the request
but mailbox had the interrupt disabled during suspend which caused the
timeout. I just re-spun the series wit hte fix. So yeah PERF_LEVEL_GET 
is expectedto work without any problems. There is no dependence on EC as
Konrad speculated. Just a straight forward case of interrupt being
disabled in the resume path.

-Sibi

> 
> Konrad