linux-kernel - Re: [PATCH v2 0/3] Power10 basic energy management

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: <cce3c51b-8614-5f4b-89ea-be5872bdcd7c@linux.ibm.com>
Date:   Mon, 13 Jul 2020 23:57:14 +0530
From:   Pratik Sampat <psampat@...ux.ibm.com>
To:     Nicholas Piggin <npiggin@...il.com>, benh@...nel.crashing.org,
        ego@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, mikey@...ling.org,
        mpe@...erman.id.au, paulus@...ba.org, pratik.r.sampat@...il.com,
        ravi.bangoria@...ux.ibm.com, svaidy@...ux.ibm.com
Subject: Re: [PATCH v2 0/3] Power10 basic energy management



On 13/07/20 10:20 pm, Nicholas Piggin wrote:
> Excerpts from Pratik Sampat's message of July 13, 2020 8:02 pm:
>> Thank you for your comments,
>>
>> On 13/07/20 10:53 am, Nicholas Piggin wrote:
>>> Excerpts from Pratik Rajesh Sampat's message of July 10, 2020 3:22 pm:
>>>> Changelog v1 --> v2:
>>>> 1. Save-restore DAWR and DAWRX unconditionally as they are lost in
>>>> shallow idle states too
>>>> 2. Rename pnv_first_spr_loss_level to pnv_first_fullstate_loss_level to
>>>> correct naming terminology
>>>>
>>>> Pratik Rajesh Sampat (3):
>>>>     powerpc/powernv/idle: Exclude mfspr on HID1,4,5 on P9 and above
>>>>     powerpc/powernv/idle: save-restore DAWR0,DAWRX0 for P10
>>>>     powerpc/powernv/idle: Rename pnv_first_spr_loss_level variable
>>>>
>>>>    arch/powerpc/platforms/powernv/idle.c | 34 +++++++++++++++++----------
>>>>    1 file changed, 22 insertions(+), 12 deletions(-)
>>> These look okay to me, but the CPU_FTR_ARCH_300 test for
>>> pnv_power9_idle_init() is actually wrong, it should be a PVR test
>>> because idle is not completely architected (not even shallow stop
>>> states, unfortunately).
>>>
>>> It doesn't look like we support POWER10 idle correctly yet, and on older
>>> kernels it wouldn't work even if we fixed newer, so ideally the PVR
>>> check would be backported as a fix in the front of the series.
>>>
>>> Sadly, we have no OPAL idle driver yet. Hopefully we will before the
>>> next processor shows up :P
>>>
>>> Thanks,
>>> Nick
>> So if I understand this correctly, in powernv/idle.c where we check for
>> CPU_FTR_ARCH_300, we should rather be making a pvr_version_is(PVR_POWER9)
>> check instead?
>>
>> Of course, the P10 PVR and its relevant checks will have to be added then too.
> Yes I think so, unfortunately.
>
> Thanks,
> Nick

Sure, I'll add these checks in.

Thanks,
Pratik