Messages in this thread | | | Date | Wed, 22 Jan 2014 12:47:58 -0800 | From | Stephen Boyd <> | Subject | Re: [PATCH v2 5/7] ARM: perf_event: Fully support Krait CPU PMU events |
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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. 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.
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.
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