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  1. 17 4月, 2013 1 次提交
    • D
      TPM: Retry SaveState command in suspend path · 32d33b29
      由 Duncan Laurie 提交于 
      If the TPM has already been sent a SaveState command before the driver
is loaded it may have problems sending that same command again later.

This issue is seen with the Chromebook Pixel due to a firmware bug in
the legacy mode boot path which is sending the SaveState command
before booting the kernel.  More information is available at
http://crbug.com/203524

This change introduces a retry of the SaveState command in the suspend
path in order to work around this issue.  A future firmware update
should fix this but this is also a trivial workaround in the driver
that has no effect on systems that do not show this problem.

When this does happen the TPM responds with a non-fatal TPM_RETRY code
that is defined in the specification:

  The TPM is too busy to respond to the command immediately, but the
  command could be resubmitted at a later time.  The TPM MAY return
  TPM_RETRY for any command at any time.

It can take several seconds before the TPM will respond again.  I
measured a typical time between 3 and 4 seconds and the timeout is set
at a safe 5 seconds.

It is also possible to reproduce this with commands via /dev/tpm0.
The bug linked above has a python script attached which can be used to
test for this problem.  I tested a variety of TPMs from Infineon,
Nuvoton, Atmel, and STMicro but was only able to reproduce this with
LPC and I2C TPMs from Infineon.

The TPM specification only loosely defines this behavior:

  TPM Main Level 2 Part 3 v1.2 r116, section 3.3. TPM_SaveState:
  The TPM MAY declare all preserved values invalid in response to any
  command other than TPM_Init.

  TCG PC Client BIOS Spec 1.21 section 8.3.1.
  After issuing a TPM_SaveState command, the OS SHOULD NOT issue TPM
  commands before transitioning to S3 without issuing another
  TPM_SaveState command.

  TCG PC Client TIS 1.21, section 4. Power Management:
  The TPM_SaveState command allows a Static OS to indicate to the TPM
  that the platform may enter a low power state where the TPM will be
  required to enter into the D3 power state.  The use of the term "may"
  is significant in that there is no requirement for the platform to
  actually enter the low power state after sending the TPM_SaveState
  command.  The software may, in fact, send subsequent commands after
  sending the TPM_SaveState command.

Change-Id: I52b41e826412688e5b6c8ddd3bb16409939704e9
Signed-off-by: NDuncan Laurie <dlaurie@chromium.org>
Signed-off-by: NKent Yoder <key@linux.vnet.ibm.com>
      32d33b29
  3. 13 4月, 2013 7 次提交
  5. 14 2月, 2013 1 次提交
  7. 05 2月, 2013 23 次提交
  9. 29 11月, 2012 2 次提交
  11. 22 11月, 2012 2 次提交
    • B
      char: remove use of __devexit · 39af33fc
      由 Bill Pemberton 提交于 
      CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Cc: Olof Johansson <olof@lixom.net>
Cc: Mattia Dongili <malattia@linux.it>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Cc: Rajiv Andrade <mail@srajiv.net>
Cc: Marcel Selhorst <tpmdd@selhorst.net>
Cc: Sirrix AG <tpmdd@sirrix.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: openipmi-developer@lists.sourceforge.net
Cc: platform-driver-x86@vger.kernel.org
Cc: tpmdd-devel@lists.sourceforge.net
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      39af33fc
    • B
      char: remove use of __devinitdata · 0bbed20e
      由 Bill Pemberton 提交于 
      CONFIG_HOTPLUG is going away as an option so __devinitdata is no
longer needed.
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Cc: Rajiv Andrade <mail@srajiv.net>
Cc: Marcel Selhorst <tpmdd@selhorst.net>
Cc: Sirrix AG <tpmdd@sirrix.com>
Cc: openipmi-developer@lists.sourceforge.net
Cc: tpmdd-devel@lists.sourceforge.net
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0bbed20e
  13. 02 11月, 2012 1 次提交
  15. 11 10月, 2012 1 次提交
    • P
      tpm: Propagate error from tpm_transmit to fix a timeout hang · abce9ac2
      由 Peter Huewe 提交于 
      tpm_write calls tpm_transmit without checking the return value and
assigns the return value unconditionally to chip->pending_data, even if
it's an error value.
This causes three bugs.

So if we write to /dev/tpm0 with a tpm_param_size bigger than
TPM_BUFSIZE=0x1000 (e.g. 0x100a)
and a bufsize also bigger than TPM_BUFSIZE (e.g. 0x100a)
tpm_transmit returns -E2BIG which is assigned to chip->pending_data as
-7, but tpm_write returns that TPM_BUFSIZE bytes have been successfully
been written to the TPM, altough this is not true (bug #1).

As we did write more than than TPM_BUFSIZE bytes but tpm_write reports
that only TPM_BUFSIZE bytes have been written the vfs tries to write
the remaining bytes (in this case 10 bytes) to the tpm device driver via
tpm_write which then blocks at

 /* cannot perform a write until the read has cleared
 either via tpm_read or a user_read_timer timeout */
 while (atomic_read(&chip->data_pending) != 0)
	 msleep(TPM_TIMEOUT);

for 60 seconds, since data_pending is -7 and nobody is able to
read it (since tpm_read luckily checks if data_pending is greater than
0) (#bug 2).

After that the remaining bytes are written to the TPM which are
interpreted by the tpm as a normal command. (bug #3)
So if the last bytes of the command stream happen to be a e.g.
tpm_force_clear this gets accidentally sent to the TPM.

This patch fixes all three bugs, by propagating the error code of
tpm_write and returning -E2BIG if the input buffer is too big,
since the response from the tpm for a truncated value is bogus anyway.
Moreover it returns -EBUSY to userspace if there is a response ready to be
read.
Signed-off-by: NPeter Huewe <peter.huewe@infineon.com>
Signed-off-by: NKent Yoder <key@linux.vnet.ibm.com>
      abce9ac2
  17. 10 10月, 2012 1 次提交
  19. 12 9月, 2012 1 次提交