On Thu, 27 Dec 2018 13:51:19 +0500 Mikhail Gavrilov mikhail.v.gavrilov@gmail.com wrote:

Hi folks. Why I cannot read content of some debugfs files which are should be readable. https://lists.freedesktop.org/archives/amd-gfx/2018-December/029918.html

[mikhail@localhost ~]$ sudo bash [sudo] password for mikhail: [root@localhost mikhail]# cd /sys/kernel/debug/dri/0 [root@localhost 0]# xxd -e amdgpu_gca_config xxd: amdgpu_gca_config: Operation not permitted [root@localhost 0]# getenforce Enforcing [root@localhost 0]# setenforce 0 [root@localhost 0]# xxd -e amdgpu_gca_config xxd: amdgpu_gca_config: Operation not permitted [root@localhost 0]#

No answer, just some further things to look at or try. I can use xxd -e on files in that directory without problem, though I don't have the file you are looking for since I use radeon.

On my system everything in there is 444 permissions, except directories. What does your system show for ls -nZ?

Can less open the file after warning you about binary data? Can you cat them into pipe to xxd? cat amd_gca_config | xxd -e -

What if you direct the output to someplace like your home directory? xxd -e amd_gca_config ~/amd_gca_config.hexdump Maybe write isn't permitted in those directories.

On Thursday, 27 December 2018 at 09:51, Mikhail Gavrilov wrote:

Hi folks. Why I cannot read content of some debugfs files which are should be readable. https://lists.freedesktop.org/archives/amd-gfx/2018-December/029918.html

[mikhail@localhost ~]$ sudo bash [sudo] password for mikhail: [root@localhost mikhail]# cd /sys/kernel/debug/dri/0 [root@localhost 0]# xxd -e amdgpu_gca_config xxd: amdgpu_gca_config: Operation not permitted [root@localhost 0]# getenforce Enforcing [root@localhost 0]# setenforce 0 [root@localhost 0]# xxd -e amdgpu_gca_config xxd: amdgpu_gca_config: Operation not permitted [root@localhost 0]#

Do you have SecureBoot enabled?

Regards, Dominik

I builded vanila kernel by this instruction: https://fedoraproject.org/wiki/Building_a_custom_kernel On vanila kernel I am able access to files which are restricted on Fedora kernel. So I think some Fedora patch is culprit here.

Is anyone here who has these patches added?

<pre> # cat /sys/kernel/debug/dri/0/amdgpu_gca_config | xxd -e - 00000000: 00000003 00000004 00000004 00000010 ................ 00000010: 00000001 00000004 00000010 00000100 ................ 00000020: 00000020 00000008 00000020 00000100 ....... ....... 00000030: 00000030 000004c0 00000000 0000ffff 0............... 00000040: 00000000 00000000 00000000 00000000 ................ 00000050: 00000000 00000000 2a114042 00000010 ........B@.*.... 00000060: 00000001 00000000 00fe9fcf 0000008d ................ 00000070: 00000001 0000687f 000000c1 00002308 .....h.......#.. 00000080: 00001458 X... </pre>