Re: About the code updte of the arc/linux/arch/beta/kernel/irq_64.c

Hi Xia,

Le 01/05/2024 à 08:22, 赵夏 a écrit :

Hi Christophe,

   I identified that the function named "arch_local_irq_restore" of the 
file irq_64.c was updated by you frequently in the last two years.

You mean arch/powerpc/kernel/irq_64.c I guess ?

I don't think I "frequently" changed it. What I did was mainly 
maintenance, I first extracted all 64 bits code from irq.c into irq_64.c 
to ease maintenance, then I did a few cosmetic changes with no 
functionnal impacts.

As far as I can see some more important changes were done by Nick, maybe 
I'll be able to answer you better. I am myself not a PPC64 expert, my 
domain in mainly PPC32.

   In the previous code version (such as Linux Kernel 5.10.7), I thought 
that an interruption such as doorbell might happen before 
"local_paca->irq_happened = 0;"  which can cause a problem. Is this the 
correct understanding? I have two questions.

   1. If the previous version can cause the problem, can the current fix 
solve the problem?
   2. If we do not care about the os performance, can we close the 
nested interrupt mechanism to avoid the problem? If we can, how to close 
the nested interrupt?

Kind regards
Xia

Thanks
Christophe