linux-kernel - Re: [PATCH v2 1/3] platform/x86/intel/tpmi: Read feature control status

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]

Date:   Wed, 12 Jul 2023 16:03:57 -0700
From:   srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     hdegoede@...hat.com, markgross@...nel.org,
        ilpo.jarvinen@...ux.intel.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] platform/x86/intel/tpmi: Read feature control
 status

On Wed, 2023-07-12 at 18:05 +0300, Andy Shevchenko wrote:
> On Tue, Jul 11, 2023 at 03:09:47PM -0700, Srinivas Pandruvada wrote:
> > Some of the PM features can be locked or disabled. In that case,
> > write
> > interface can be locked.
> > 
> > This status is read via a mailbox. There is one TPMI ID which
> > provides
> > base address for interface and data register for mail box
> > operation.
> > The mailbox operations is defined in the TPMI specification. Refer
> > to
> > https://github.com/intel/tpmi_power_management/ for TPMI
> > specifications.
> > 
> > An API is exposed to feature drivers to read feature control
> > status.
> 
> ...
> 
> > +/*
> > + * TPMI PFS and per feature memory size can't exceed 4K.
> > + * Also PFS start and feature memory is 4K aligned.
> > + */
> > +#define TPMI_MAX_BUFFER_SIZE    (4 * 1024)
> 
> SZ_4K from sizes.h?
> 
> ...
I added a macro for size and uses sizes.h define.

> 
> > +#define TPMI_CONTROL_TIMEOUT_MAX_US    USEC_PER_SEC
> 
> > +#define TPMI_RB_TIMEOUT_MAX_US         USEC_PER_SEC
> 
> I think it's easier to get in a form (1 * ..._SEC)
> 
OK

> ...
> 
> > +static int tpmi_wait_for_owner(struct intel_tpmi_info *tpmi_info,
> > u8 owner)
> > +{
> > +       u64 control;
> > +
> > +       return read_poll_timeout(readq, control,
> > +                                owner ==
> > FIELD_GET(TPMI_CONTROL_STATUS_OWNER, control),
> > +                                TPMI_CONTROL_TIMEOUT_US,
> > TPMI_CONTROL_TIMEOUT_MAX_US, false,
> > +                                tpmi_info->tpmi_control_mem +
> > TPMI_CONTROL_STATUS_OFFSET);
> 
> Since you have "false" why not use readq_poll_timeout()?
> 
Changed in new version

> > +}
> 
> ...
> 
> > +       /* Wait for Run Busy clear */
> > +       ret = read_poll_timeout(readq, control, !(control &
> > TPMI_CONTROL_STATUS_RB),
> > +                               TPMI_RB_TIMEOUT_US,
> > TPMI_RB_TIMEOUT_MAX_US, false,
> > +                               tpmi_info->tpmi_control_mem +
> > TPMI_CONTROL_STATUS_OFFSET);
> 
> Ditto.
Done.

> 
> > +       if (ret)
> > +               goto done_proc;
> 
> ...
> 
> > +       size = pfs->pfs_header.num_entries * pfs-
> > >pfs_header.entry_size * sizeof(u32);
> > +       /* This size is coming from trusted hardware, but verify
> > anyway */
> 
> I would move this comment before size assignment that we already know
> that it's
> from the trusted hw.
Created a macro.

Thanks,
Srinivas

> 
> > +       if (size > TPMI_MAX_BUFFER_SIZE)
> > +               return;
>