lkml.org 
[lkml]   [2021]   [Jan]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] tpm/tpm_tis: Fix variable reset during IRQ probing
From
Date


On 1/15/21 5:23 PM, Jarkko Sakkinen wrote:
> On Thu, Jan 14, 2021 at 12:12:16PM +0800, Tianjia Zhang wrote:
>>
>>
>> On 1/14/21 10:51 AM, Jarkko Sakkinen wrote:
>>> On Wed, Jan 13, 2021 at 08:00:21PM +0800, Tianjia Zhang wrote:
>>>> In tpm_tis_core_init(), tpm2_probe() will be called first, this
>>>> function will eventually call tpm_tis_send(), and then
>>>> tpm_tis_probe_irq_single() will detect whether the interrupt is
>>>> normal, mainly the installation interrupted, set `priv->irq_tested`
>>>> to false. The logic will eventually be executed to tpm_tis_send()
>>>> to trigger an interrupt.
>>>>
>>>> There is currently such a scenario, which will cause the IRQ probe
>>>> code to never be executed, so that the TPM device is in polling
>>>> mode: after setting irq_tested to false, an interrupt occurs
>>>> between entering the ttpm_tis_send() function, and the interrupt
>>>> will be first set irq_tested to true will cause the IRQ probe code
>>>> to never be executed.
>>>
>>> Can you describe the scenario more detail?
>>>
>>
>> The problematic scenario we encountered is like this. The following figure
>> shows the execution flow of tpm_tis_core_init(). An interrupt occurred
>> before the IRQ probe. This interrupt was caused by tpm2_probe(), but it was
>> triggered before the IRQ probe was executed, and the interrupt handler would
>> set irq_tested to true, so the IRQ probe code can never execute, that is,
>> the code marked 2 in the figure will never happen.
>
> TPM_INT_ENABLE is cleared on reset [*].
>
> [*] Section 5.9.1
> https://trustedcomputinggroup.org/resource/pc-client-work-group-pc-client-specific-tpm-interface-specification-tis/
>
> /Jarkko
>

Hi,

I got it, this seems to be a firmware issue. Thanks for your reply.

Best regards,
Tianjia

\
 
 \ /
  Last update: 2021-01-20 05:07    [W:0.049 / U:0.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site