DRA750: how to enable Hardlockup detector in linux kernel

HI

Can you clarify on what you mean by "support is not available"

Lockup detection is a standard kernel feature and needs to be enabled through kernel configuration 

Have you looked up at usage instructions from the kernel documentation

Hi Sriram,

Thank you for the reply.

In kernel we have  support for detecting softlock_up & hardlock_up.

It is present at  kernel/watchdog.c .

To enable the HARDLOCKUP :

HARDLOCKUP_DETECTOR is depends on below configs

Depends on: LOCKUP_DETECTOR [=y] && !HAVE_NMI_WATCHDOG [=n] && PERF_EVENTS [=y] && HAVE_PERF_EVENTS_NMI [=n]

HAVE_PERF_EVENTS_NMI config need to be enabled.

Symbol: HAVE_PERF_EVENTS_NMI [=n]

  Type  : boolean                                                                                                                                                                      

    Defined at arch/Kconfig:271

But not sure here how to enable this. 

Thanks,

Viswa

Viswa

You can use menuconfig I/F to review and modify kernel configuration

Hi Sriram,

Below are my findings

Detection of hard lockup in arm cortex a15 processor doesn't seem to be a straight forward way as it seems to be in intel processor.
This is because of lack of NMI support on cortex A15 processors.
so we are trying to find out alternative ways to detect the hard lockup in arm cortex a15.
for your reference, below are the links to sources from which I have confirmed the missing NMI on cortex A15

https://e2e.ti.com/support/processors/f/791/t/597890?Linux-DRA744-Using-NMIN-as-normal-interrupt-from-A15-MPCore

the other way is to use the other cpu to detect hardlockup, below is the patch

https://patchwork.kernel.org/patch/1967551/

there is one more way to simulate NMI using PMU & FIQ, below is the reference link

https://www.linaro.org/blog/debugging-arm-kernels-using-nmifiq/

please let me know if you have any thoughts on the same.

Thanks,
Viswa

Viswa

Ok, but are you sure the condition that you are trying to debug is indeed a Hard lock up condition.

have you checked if the softlockup detector and additional kernel hacking options for lock debugging are of any help?

Dont think i have an answer for enabling support for Hard lockup detection

Hi Sriram,

Thank you for the reply.

Soft lockup is working & the cpu backtrace is also available. but for hardlockup not getting any trace.

will check other hacking options for lock debugging.

Thanks,

Viswa