linux-kernel - Re: [PATCH RESEND 1/2] thermal: intel: Prevent accidental clearing of HFI status

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Date:   Fri, 18 Nov 2022 11:35:18 -0800
From:   srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     daniel.lezcano@...aro.org, amitk@...nel.org, rui.zhang@...el.com,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Subject: Re: [PATCH RESEND 1/2] thermal: intel: Prevent accidental clearing
 of HFI status

On Fri, 2022-11-18 at 18:54 +0100, Rafael J. Wysocki wrote:
> On Wed, Nov 16, 2022 at 3:54 AM Srinivas Pandruvada
> <srinivas.pandruvada@...ux.intel.com> wrote:
> > 
> > When there is a package thermal interrupt with PROCHOT log, it will
> > be
> > processed and cleared. It is possible that there is an active HFI
> > event
> > status, which is about to get processed or getting processed. While
> > clearing PROCHOT log bit, it will also clear HFI status bit. This
> > means
> > that hardware is free to update HFI memory.
> > 
> > When clearing a package thermal interrupt, some processors will
> > generate
> > a "general protection fault" when any of the read only bit is set
> > to 1.
> > The driver maintains a mask of all read-write bits which can be
> > set.
> > This mask doesn't include HFI status bit. This bit will also be
> > cleared,
> > as it will be assumed read-only bit. So, add HFI status bit 26 to
> > the
> > mask.
> > 
> > Signed-off-by: Srinivas Pandruvada
> > <srinivas.pandruvada@...ux.intel.com>
> > Reviewed-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
> 
> Is a Fixes tag missing here?
While adding the following change, this should have been take care of:
ab09b0744a99 ("thermal: intel: hfi: Enable notification interrupt")

But the above change didn't add this line, which this patch is
changing. We can add:

Fixes: ab09b0744a99 ("thermal: intel: hfi: Enable notification
interrupt")

Do you want me to send another PATCH with fixes.

> 
> Also, do you want it in 6.1-rc7 or would 6.2 suffice?
Not urgent. 6.2 should be fine.

Thanks,
Srinivas

> 
> > ---
> > Email address was wrong, so sending again.
> > 
> >  drivers/thermal/intel/therm_throt.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/thermal/intel/therm_throt.c
> > b/drivers/thermal/intel/therm_throt.c
> > index 8352083b87c7..9e8ab31d756e 100644
> > --- a/drivers/thermal/intel/therm_throt.c
> > +++ b/drivers/thermal/intel/therm_throt.c
> > @@ -197,7 +197,7 @@ static const struct attribute_group
> > thermal_attr_group = {
> >  #define THERM_STATUS_PROCHOT_LOG       BIT(1)
> > 
> >  #define THERM_STATUS_CLEAR_CORE_MASK (BIT(1) | BIT(3) | BIT(5) |
> > BIT(7) | BIT(9) | BIT(11) | BIT(13) | BIT(15))
> > -#define THERM_STATUS_CLEAR_PKG_MASK  (BIT(1) | BIT(3) | BIT(5) |
> > BIT(7) | BIT(9) | BIT(11))
> > +#define THERM_STATUS_CLEAR_PKG_MASK  (BIT(1) | BIT(3) | BIT(5) |
> > BIT(7) | BIT(9) | BIT(11) | BIT(26))
> > 
> >  static void clear_therm_status_log(int level)
> >  {
> > --
> > 2.31.1
> >