Re: [PATCH v2 3/3] arm64: perf: Add support for ARMv8.5-PMU 64-bit counters

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On 10/12/2019 12:01, Andrew Murray wrote:
At present ARMv8 event counters are limited to 32-bits, though by
using the CHAIN event it's possible to combine adjacent counters to
achieve 64-bits. The perf config1:0 bit can be set to use such a
configuration.

With the introduction of ARMv8.5-PMU support, all event counters can
now be used as 64-bit counters.

Let's enable 64-bit event counters where support exists. Unless the
user sets config1:0 we will adjust the counter value such that it
overflows upon 32-bit overflow. This follows the same behaviour as
the cycle counter which has always been (and remains) 64-bits.

Signed-off-by: Andrew Murray <andrew.murray@xxxxxxx>

Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
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