From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:33541 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754772AbeBAUgB (ORCPT ); Thu, 1 Feb 2018 15:36:01 -0500 Received: by mail-wm0-f65.google.com with SMTP id x4-v6so1732757wmc.0 for ; Thu, 01 Feb 2018 12:36:01 -0800 (PST) Date: Thu, 1 Feb 2018 13:35:56 -0700 From: Jason Gunthorpe To: James Bottomley Cc: Paul Menzel , linux-integrity Subject: Re: TPM selftest failure in 4.15 Message-ID: <20180201203556.GX17053@ziepe.ca> References: <1517487371.3251.9.camel@HansenPartnership.com> <1517488970.3251.26.camel@HansenPartnership.com> <1517498648.3145.4.camel@HansenPartnership.com> <20180201174053.GQ17053@ziepe.ca> <1517510764.3145.38.camel@HansenPartnership.com> <20180201185909.GW17053@ziepe.ca> <1517515204.3145.51.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1517515204.3145.51.camel@HansenPartnership.com> Sender: linux-integrity-owner@vger.kernel.org List-ID: On Thu, Feb 01, 2018 at 09:00:04PM +0100, James Bottomley wrote: > On Thu, 2018-02-01 at 11:59 -0700, Jason Gunthorpe wrote: > > On Thu, Feb 01, 2018 at 07:46:04PM +0100, James Bottomley wrote: > > > > > > > > I honestly don't think we should be waiting for the self test at > > > all. > > > We should kick it off and treat any TPM_RC_TESTING error as > > > -EAGAIN. > > > We're already under fire for slow boot sequences and adding 2s just > > > to > > > wait for the TPM to self test adds to that for no real value. > > > > Arguably the BIOS should have completed the selftest - this stuff > > generally only exists to support embedded. > > > > I don't like the idea of EAGAIN, that just expose all our users to > > this mess. > > > > I would support making transmit_cmd genericly wait and retry if the > > TPM insists we need to wait for selftest to complete the specific > > command though. > > OK, how about this then? Yeah, I like this concept much better, thanks > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > index 1d6729be4cd6..84ed271c060b 100644 > +++ b/drivers/char/tpm/tpm-interface.c > @@ -521,12 +521,32 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space, > const struct tpm_output_header *header = buf; > int err; > ssize_t len; > + unsigned int delay_msec = 20; > > - len = tpm_transmit(chip, space, (u8 *)buf, bufsiz, flags); > - if (len < 0) > - return len; > + /* > + * on first probe we kick off a TPM self test in the > + * background This means the TPM may return RC_TESTING to any > + * command that tries to use a subsystem under test, so do an > + * exponential backoff wait if that happens > + */ > + for (;;) { > + len = tpm_transmit(chip, space, (u8 *)buf, bufsiz, flags); > + if (len < 0) > + return len; > + > + err = be32_to_cpu(header->return_code); > + if (err != TPM2_RC_TESTING || > + (flags & TPM_TRANSMIT_NOWAIT)) > + break; Do TPM and TPM2 use a different return code here? Jason