From: Kent Yoder <key@linux.vnet.ibm.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Peter.Huewe@infineon.com, linux-kernel@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net
Subject: Re: [tpmdd-devel] [PATCH] TPM: Issue TPM_STARTUP at driver load if the TPM has not been started
Date: Mon, 1 Oct 2012 12:10:03 -0500 [thread overview]
Message-ID: <20121001171003.GA1117@ennui.austin.ibm.com> (raw)
In-Reply-To: <20121001161536.GC31620@obsidianresearch.com>
On Mon, Oct 01, 2012 at 10:15:36AM -0600, Jason Gunthorpe wrote:
> On Mon, Oct 01, 2012 at 09:17:28AM +0000, Peter.Huewe@infineon.com wrote:
> > Hi Jason,
> >
> > > The TPM will respond to TPM_GET_CAP with TPM_ERR_INVALID_POSTINIT if
> > > TPM_STARTUP has not been issued. This will result in the TPM driver
> > > failing to load and no way to recover. Detect this and automatically
> > > issue TPM_STARTUP.
> >
> > > This is for embedded applications where the kernel is the first thing
> > > to touch the TPM.
> >
> > Thanks for working on this.
> > I also thought about this scenario quite often.
> >
> > Shouldn't we then also add a TpmStartup(ST_STATE) in case of a resume?
> > rc=GetCapability()
> > if(rc==INVALID_POSTINIT)
> > tpm_transmit ("TPM_STARTUP(ST_STATE)")...
>
> I'm not familiar enough with how the power management flow works with
> the TPM to do this. I don't think that can be the general case
> because:
>
> 3. If stType = TPM_ST_STATE
> a. If the TPM has no state to restore, the TPM MUST set the internal
> state such that it returns TPM_FAILEDSELFTEST to all subsequent
> commands.
>
> So you need to know a save state exists in the TPM before attempting
> the command?
Presumably we'd have called TPM_SaveState on suspend. It might be
possible to set a flag based on whether we needed to call startup at
init time that tells the driver to call save/restore state during
suspend/resume.
Kent
> Would you agree that CLEAR is appropriate for an initial driver
> attach on probe?
>
> Jason
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
next prev parent reply other threads:[~2012-10-01 17:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-30 23:30 [PATCH] TPM: Issue TPM_STARTUP at driver load if the TPM has not been started Jason Gunthorpe
2012-10-01 9:17 ` [tpmdd-devel] " Peter.Huewe
2012-10-01 16:15 ` Jason Gunthorpe
2012-10-01 17:10 ` Kent Yoder [this message]
2012-10-01 17:39 ` Jason Gunthorpe
2012-10-04 17:41 ` Kent Yoder
2012-10-04 18:02 ` Jason Gunthorpe
2012-10-08 7:09 ` Peter.Huewe
2012-11-21 7:10 ` [PATCH resend] " Jason Gunthorpe
2012-11-21 8:59 ` Peter.Huewe
2012-11-21 17:29 ` Jason Gunthorpe
2012-11-21 17:37 ` Peter.Huewe
2012-11-21 18:37 ` [PATCH v4] " Jason Gunthorpe
2012-11-21 20:17 ` Peter Hüwe
2012-11-21 20:12 ` Jason Gunthorpe
2012-11-21 20:54 ` [PATCH v5] " Jason Gunthorpe
2012-11-26 20:08 ` Kent Yoder
2012-10-01 15:14 ` [PATCH] " Kent Yoder
[not found] <4347_1349050738_q910IviQ005340_20120930233012.GH30637@obsidianresearch.com>
2012-10-01 12:57 ` [tpmdd-devel] " Jonathan McCune
2012-10-01 15:15 ` Peter.Huewe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121001171003.GA1117@ennui.austin.ibm.com \
--to=key@linux.vnet.ibm.com \
--cc=Peter.Huewe@infineon.com \
--cc=jgunthorpe@obsidianresearch.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tpmdd-devel@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).