Re: [PATCH v4 4/5] arm64/perf: Enable PMCR long cycle counter bit

From: Jan Glauber
Date: Thu Feb 18 2016 - 13:29:16 EST


On Thu, Feb 18, 2016 at 05:34:28PM +0000, Will Deacon wrote:
> On Thu, Feb 18, 2016 at 05:50:13PM +0100, Jan Glauber wrote:
> > With the long cycle counter bit (LC) disabled the cycle counter is not
> > working on ThunderX SOC (ThunderX only implements Aarch64).
> > Also, according to documentation LC == 0 is deprecated.
> >
> > To keep the code simple the patch does not introduce 64 bit wide counter
> > functions. Instead writing the cycle counter always sets the upper
> > 32 bits so overflow interrupts are generated as before.
> >
> > Original patch from Andrew Pinksi <Andrew.Pinksi@xxxxxxxxxxxxxxxxxx>
>
> What does this mean? Do we need Andrew's S-o-B, or is this a fresh patch?
>
> Will

I've modified Andrew's patch. I assumed his formal S-o-B is not
required. Please correct me if I'm wrong.

Jan