Bug 1598249 - TPM drivers are built-in in the kernel instead of being .ko modules, so it's not possible to blacklist them.
Summary: TPM drivers are built-in in the kernel instead of being .ko modules, so it's ...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 28
Hardware: Unspecified
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-07-04 22:05 UTC by Damián Barberón
Modified: 2018-07-05 15:22 UTC (History)
18 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2018-07-05 15:22:06 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description Damián Barberón 2018-07-04 22:05:29 UTC
Hi Fedora Devs.
Description of problem:

Everytime system boots, I get the following message related to another bug:

tpm_crb MSFT0101:00: [Firmware Bug]: ACPI region does not cover the entire command/response buffer. [mem 0xfed40000-0xfed4087f flags 0x200] vs fed40080 f80

For this reason, I decided to disable the TPM chip by adding the tpm and tpm_crb driver to the module blacklist with no favorable results.

After recents kernel updates (4.17 series), I observed that this two drivers are compiled "built-in" inside the kernel, with no posibility to blacklist them at boot.

With 4.16 kernel series, I remember that tpm and tpm_crb drivers was configured as loadable modules with posibility to disable TPM chip by blacklisting them. 
   
Steps to Reproduce:
1. Boot Fedora 28 with recent kernel updates (i.e. 4.17.3) on a laptop with TPM chip.
2. Run lsmod. It doesn't show the tpm related modules.
3. Run dmesg, and the output shows that the kernel automatically inserts and load TPM drivers at boot.

Actual results:
It's not possible to disable TPM chip by blacklisting tpm related modules.

Expected results:
Take the advantage of linux loadable modules configuring TPM related drviers as driver.ko enabling the user to blacklist them as needed. 

Additional info:

Comment 1 Yanko Kaneti 2018-07-05 11:01:52 UTC
Other than the message is there any other noticeable regression ?

Comment 2 Laura Abbott 2018-07-05 15:22:06 UTC
Yes, this is intentional. We changed TPM to be built in because we eventually want to turn on IMA which relies on the TPM. As the message notes, it's a firmware bug but things should still be functional. If there are other issue besides the firmware message, feel free to reopen the bug.


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