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Message-ID: <20161020140011.s5mu3atjjwnwqda4@intel.com>
Date: Thu, 20 Oct 2016 17:00:11 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: "Winkler, Tomas" <tomas.winkler@...el.com>
Cc: "tpmdd-devel@...ts.sourceforge.net"
<tpmdd-devel@...ts.sourceforge.net>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [tpmdd-devel] [PATCH] tpm, tpm_crb: remove redundant
CRB_FL_CRB_START flag
On Thu, Oct 20, 2016 at 04:59:06PM +0300, Jarkko Sakkinen wrote:
> On Wed, Oct 19, 2016 at 07:09:28PM +0300, Jarkko Sakkinen wrote:
> > On Wed, Oct 19, 2016 at 10:28:29AM +0000, Winkler, Tomas wrote:
> > >
> > >
> > > >
> > > > On Mon, Oct 17, 2016 at 11:42:24PM +0300, Jarkko Sakkinen wrote:
> > > > > Because all the existing hardware have HID MSFT0101 we end up always
> > > > > setting CRB_FL_CRB_START flag as a workaround for 4th Gen Core CPUs.
> > > > > Even if ACPI start is used, the driver will always issue also CRB start.
> > >
> > > Do you have some more historical data about this fix, I was wondering
> > > about this quirk before, when restructuring the start method parsing.
> > > The description is ' in practice seems to require both' sounds not
> > > certain about the root cause of this.
> >
> > I have a 4th Gen Core NUC where I experienced this issue. It reported
> > requiring only ACPI start but actually required ACPI + CRB start. The
> > comment could have been better.
>
> With the latest master branch if I remove the workaround:
>
> [ 395.161155] tpm_crb: module verification failed: signature and/or required key missing - tainting kernel
> [ 480.087136] tpm tpm0: A TPM error (323) occurred continue selftest
> [ 480.087141] tpm tpm0: TPM self test failed
>
> jsakkine at jsakkine-tpm1 in ~/devel/linux-tpmdd (master●●)
> $ git --no-pager diff
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 65040d7..5b186e0 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -407,14 +407,6 @@ static int crb_acpi_add(struct acpi_device *device)
> if (!priv)
> return -ENOMEM;
>
> - /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
> - * report only ACPI start but in practice seems to require both
> - * ACPI start and CRB start.
> - */
> - if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
> - !strcmp(acpi_device_hid(device), "MSFT0101"))
> - priv->flags |= CRB_FL_CRB_START;
> -
> if (sm == ACPI_TPM2_START_METHOD ||
> sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
> priv->flags |= CRB_FL_ACPI_START;
>
> jsakkine at jsakkine-tpm1 in ~/devel/linux-tpmdd (master●●)
> $ sudo dmidecode -t bios -q
> BIOS Information
> Vendor: Intel Corp.
> Version: WYLPT10H.86A.0033.2014.1201.0940
> Release Date: 12/01/2014
> Address: 0xF0000
> Runtime Size: 64 kB
> ROM Size: 6656 kB
> Characteristics:
> PCI is supported
> BIOS is upgradeable
> BIOS shadowing is allowed
> Boot from CD is supported
> Selectable boot is supported
> BIOS ROM is socketed
> EDD is supported
> 5.25"/1.2 MB floppy services are supported (int 13h)
> 3.5"/720 kB floppy services are supported (int 13h)
> 3.5"/2.88 MB floppy services are supported (int 13h)
> Print screen service is supported (int 5h)
> Serial services are supported (int 14h)
> Printer services are supported (int 17h)
> ACPI is supported
> USB legacy is supported
> BIOS boot specification is supported
> Targeted content distribution is supported
> UEFI is supported
> BIOS Revision: 4.6
>
> BIOS Language Information
> Language Description Format: Long
> Installable Languages: 1
> en|US|iso8859-1
> Currently Installed Language: en|US|iso8859-1
>
> jsakkine at jsakkine-tpm1 in ~/tmp (master)
> $ cat ~/tmp/tpm2.dsl
> /*
> * Intel ACPI Component Architecture
> * AML Disassembler version 20140214-64 [Mar 29 2014]
> * Copyright (c) 2000 - 2014 Intel Corporation
> *
> * Disassembly of tpm2.dat, Wed Jun 1 16:26:49 2016
> *
> * ACPI Data Table [TPM2]
> *
> * Format: [HexOffset DecimalOffset ByteLength] FieldName : FieldValue
> */
>
> [000h 0000 4] Signature : "TPM2" [Trusted Platform Module hardware interface table]
> [004h 0004 4] Table Length : 00000034
> [008h 0008 1] Revision : 03
> [009h 0009 1] Checksum : 31
> [00Ah 0010 6] Oem ID : "INTEL "
> [010h 0016 8] Oem Table ID : "D34010WY"
> [018h 0024 4] Oem Revision : 00000021
> [01Ch 0028 4] Asl Compiler ID : ""
> [020h 0032 4] Asl Compiler Revision : 00000000
>
> [024h 0036 4] Flags : 00000000
> [028h 0040 8] Control Address : 00000000DBFFF000
> [030h 0048 4] Start Method : 00000002
>
> Raw Table Data: Length 52 (0x34)
>
> 0000: 54 50 4D 32 34 00 00 00 03 31 49 4E 54 45 4C 20 TPM24....1INTEL
> 0010: 44 33 34 30 31 30 57 59 21 00 00 00 00 00 00 00 D34010WY!.......
> 0020: 00 00 00 00 00 00 00 00 00 F0 FF DB 00 00 00 00 ................
> 0030: 02 00 00 00 ....
>
> Obviously I'm going to keep the work around because I don't want to risk
> breaking machines in the field. Because as a side effect for any machine
> the driver always invokes CRB start I will definitely want to simplify
> the state of the driver.
Oops. I forgot to mension the device: D34010WYK
http://www.intel.com/content/www/us/en/nuc/nuc-kit-d34010wyk-board-d34010wyb.html
/Jarkko
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