printk 100% interrupt safe?

[Joel Sherrill]

"Smith, Gene" wrote:
> 
> Does anyone know if the printk function is interrupt safe, i.e., reentrant?
> On some boards, I am seeing a spurious interrupt that is *supposed* to be
> disabled and masked. Yet it still occurs maybe once per hour. The default
> handler for the interrupt just printk's a short message. On boards that
> produce the spurious interrupt, a random crash occurs after more than 24
> hours. I have never seen a crash on boards that don't produce the spurious
> interrupt. I have taken the printk out of the default handlers and will see
> if that helps.  (The spurious interrupt might be caused by the non-standard
> interrupt controller I am using.)

My reading is that printk does not define any global or static variables
so that much is reentrant safe.  The next thing is examining what it
calls:

bash$ sparc-rtems-nm --extern-only printk.o 
         U .udiv
         U .umul
         U BSP_output_char
00000000 T printk

So only BSP_output_char is referenced.  As long as the disable/enable
interrupt are properly paired and enable just restores things clenaly
to their state pre-disable, then it should be fine.

The big question mark is what does your BSP_output_char do?

> Any information would be most appreciated.
> 
> -gene

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