Messages in this thread | | | Subject | Re: [PATCH v2 2/3] powerpc/powernv/idle: save-restore DAWR0, DAWRX0 for P10 | From | Ravi Bangoria <> | Date | Mon, 20 Jul 2020 10:00:56 +0530 |
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Hi Nick,
On 7/13/20 11:22 AM, Nicholas Piggin wrote: > Excerpts from Pratik Rajesh Sampat's message of July 10, 2020 3:22 pm: >> Additional registers DAWR0, DAWRX0 may be lost on Power 10 for >> stop levels < 4. >> Therefore save the values of these SPRs before entering a "stop" >> state and restore their values on wakeup. > > Hmm, where do you get this from? Documentation I see says DAWR is lost > on POWER9 but not P10. > > Does idle thread even need to save DAWR, or does it get switched when > going to a thread that has a watchpoint set?
I don't know how idle states works internally but IIUC, we need to save/restore DAWRs. This is needed when user creates per-cpu watchpoint event.
Ravi
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