Messages in this thread | | | Date | Thu, 23 Jan 2014 10:32:16 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v2 5/7] ARM: perf_event: Fully support Krait CPU PMU events |
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On Wed, Jan 22, 2014 at 08:47:58PM +0000, Stephen Boyd wrote: > On 01/21/14 10:37, Stephen Boyd wrote: > > On 01/21/14 10:07, Will Deacon wrote: > >> Do you need isbs to ensure the pmresrn side-effects have happened, or are > >> the registers self-synchronising? Similarly for your other IMP DEF > >> registers. > > There aren't any isbs in the downstream android sources so I assume > > they're self synchronizing. I'll confirm with the CPU designers to make > > sure. > > > > CPU folks say no need for isb.
Good, good!
> They mentioned that the lack of an isb after the > armv7_pmnc_enable_counter() call will leave the action of enabling the > counter "in-flight". The window is probably pretty short on an SMP kernel > because of the spin_unlock right after with the barriers in it, but the > same can't be said for a UP kernel.
Yep, we rely on the exception return for that.
> Also, the fuzzer didn't find anything else, but I found a bug in the > bitmap logic, updated and reran the fuzzer this morning. Everything > looks good.
Okey doke, I guess if you can repost at -rc1 then I can look at pulling this into my tree.
Cheers,
Will
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