Dear all,
I am trying to demystify what happens when the kernel has configured to use
LAPIC timer as its timer and I've ran into some problems/questions.
AFAIK, when a LAPIC timer interrupt occurs, the assembly wrapper at
enrty_32.s jumps the execution at smp_apic_timer_interrupt(). At the
beginning of this function, I've checked to see if interrupts are enabled or
not using irqs_disabled() and I found out that they are disabled.
The problem is that I can't find where Linux disables interrupts before
calling smp_apic_timer_interrupt(). The only place this could be done is in
the assembly wrapper but I can't really find it.
Does the processor disables interrupts by default when a LAPIC timer
interrupt occurs?
Any help will be much appreciated.
Thanks in advance.
John.