From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Safford, David (GE Global Research, US)" <david.safford@ge.com>
Cc: "linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"jarkko.sakkinen@linux.intel.com"
<jarkko.sakkinen@linux.intel.com>,
"Wiseman, Monty (GE Global Research, US)" <monty.wiseman@ge.com>
Subject: Re: [PATCH] tpm_crb - workaround broken ACPI tables
Date: Thu, 11 Jul 2019 11:58:50 -0300 [thread overview]
Message-ID: <20190711145850.GC25807@ziepe.ca> (raw)
In-Reply-To: <BCA04D5D9A3B764C9B7405BBA4D4A3C035EF7BC7@ALPMBAPA12.e2k.ad.ge.com>
On Thu, Jul 11, 2019 at 12:29:30PM +0000, Safford, David (GE Global Research, US) wrote:
> Most x86 desktops and laptops have firmware TPMs which support the
> CRB interface. Unfortunately, the linux tpm_crb driver depends on
> perfectly correct ACPI tables, and there are a *lot* of systems out
> there with broken tpm_crb entries. (Not one of my five tpm_crb
> systems works with the existing driver.) While it is good to
> encourage vendors to fix their firmware, many refuse ("It works on
> Windows"), leaving users in the lurch.
>
> This patch adds a kernel parameter "tpm_crb.force=1" that works
> around the problem in every case I have tested so far. Basically
> it does two things:
> - it trusts the cmd and resp addresses in the CRB registers
> - it ignores all alleged IO resource conflicts
>
> Both workarounds make sense. If there really were an address conflict,
> or if the register values really were wrong, the device would not be
> working at all. And testing with this patch has shown that in every
> case (so far), the problem has been bogus ACPI entries.
>
> This patch is against the upstream 5.2 kernel.
>
> Signed-off-by: David Safford <david.safford@ge.com>
I think we need to ask the ioresource and ACPI people how to fix this
properly and automatically. Maybe some ACPI quirk or maybe we try to
resorve the resoruce and fall back to forcing or something
I don't think t a module parameter is the right answer
Jaason
next prev parent reply other threads:[~2019-07-11 14:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 12:29 [PATCH] tpm_crb - workaround broken ACPI tables Safford, David (GE Global Research, US)
2019-07-11 14:10 ` Jarkko Sakkinen
2019-07-11 14:58 ` Jason Gunthorpe [this message]
2019-07-11 16:44 ` Safford, David (GE Global Research, US)
2019-07-11 18:50 ` Jason Gunthorpe
2019-07-11 19:31 ` Safford, David (GE Global Research, US)
2019-07-11 20:33 ` Matthew Garrett
2019-07-12 12:41 ` Safford, David (GE Global Research, US)
2019-07-12 15:06 ` Jason Gunthorpe
2019-07-12 15:48 ` Jarkko Sakkinen
2019-07-12 18:24 ` Matthew Garrett
2019-07-12 19:05 ` Safford, David (GE Global Research, US)
2019-07-12 20:36 ` Matthew Garrett
2019-07-14 19:28 ` Safford, David (GE Global Research, US)
2019-07-14 23:48 ` Matthew Garrett
2019-07-15 19:44 ` Matthew Garrett
2019-07-11 19:16 ` Jarkko Sakkinen
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