AMD Zen 2 introduces the RDPRU instruction which can be used to access some
processor registers which are typically only accessible in privilege level
0. ECX specifies the register to read and EDX:EAX will contain the value read.
ECX: 0 - Register MPERF
1 - Register APERF
This has the added advantage of not having to use the msr module, since the
userspace to kernel transitions which occur during each read_msr() might
cause APERF and MPERF to go out of sync.
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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