[Skiboot] question about sbe-p9 timer

Thiago Jung Bauermann bauerman at linux.ibm.com
Thu Feb 13 03:32:05 AEDT 2020


I've been studying the timer code in hw/sbe-p9.c and I have a question
regarding concurrency: I noticed that in almost all cases,
sbe_last_gen_stamp is accessed with sbe->lock held (where sbe is the
default chip).

Except in one case: p9_sbe_update_timer_expiry() calls
p9_sbe_timer_schedule() - which reads sbe_last_gen_stamp - without
acquiring sbe->lock. Is this a problem that needs to be fixed?

Thiago Jung Bauermann
IBM Linux Technology Center

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