I am interested to know if timer interrupts can be masked.. ? Consider a case of ppc, run_local_timers() function in “kernel/timer.c” is called by the local, per-CPU timer interrupt.
So is there any possibility that this timer interrupt is masked and run_local_timers() function is not called during that time?
All interrupts, except NMI, can be masked. This includes the timer interrupt.
In general, while hardware interrupts are being processed, interrupts are disabled.
Note that masking interrupts for more than a very short while affects the system badly.