Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

tpm: tis: Double the timeout B to 4s

With some Infineon chips the timeouts in tpm_tis_send_data (both B and
C) can reach up to about 2250 ms.

Timeout C is retried since
commit de9e33df7762 ("tpm, tpm_tis: Workaround failed command reception on Infineon devices")

Timeout B still needs to be extended.

The problem is most commonly encountered with context related operation
such as load context/save context. These are issued directly by the
kernel, and there is no retry logic for them.

When a filesystem is set up to use the TPM for unlocking the boot fails,
and restarting the userspace service is ineffective. This is likely
because ignoring a load context/save context result puts the real TPM
state and the TPM state expected by the kernel out of sync.

Chips known to be affected:
tpm_tis IFX1522:00: 2.0 TPM (device-id 0x1D, rev-id 54)
Description: SLB9672
Firmware Revision: 15.22

tpm_tis MSFT0101:00: 2.0 TPM (device-id 0x1B, rev-id 22)
Firmware Revision: 7.83

tpm_tis MSFT0101:00: 2.0 TPM (device-id 0x1A, rev-id 16)
Firmware Revision: 5.63

Link: https://lore.kernel.org/linux-integrity/Z5pI07m0Muapyu9w@kitsune.suse.cz/
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

authored by

Michal Suchanek and committed by
Jarkko Sakkinen
2f661f71 32d495b3

+2 -2
+1 -1
drivers/char/tpm/tpm_tis_core.h
··· 54 54 enum tis_defaults { 55 55 TIS_MEM_LEN = 0x5000, 56 56 TIS_SHORT_TIMEOUT = 750, /* ms */ 57 - TIS_LONG_TIMEOUT = 2000, /* 2 sec */ 57 + TIS_LONG_TIMEOUT = 4000, /* 4 secs */ 58 58 TIS_TIMEOUT_MIN_ATML = 14700, /* usecs */ 59 59 TIS_TIMEOUT_MAX_ATML = 15000, /* usecs */ 60 60 };
+1 -1
include/linux/tpm.h
··· 224 224 225 225 enum tpm2_timeouts { 226 226 TPM2_TIMEOUT_A = 750, 227 - TPM2_TIMEOUT_B = 2000, 227 + TPM2_TIMEOUT_B = 4000, 228 228 TPM2_TIMEOUT_C = 200, 229 229 TPM2_TIMEOUT_D = 30, 230 230 TPM2_DURATION_SHORT = 20,