linux-kernel - Re: [PATCH 1/3] perf/x86/intel/pt: Add new timing packet enables

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Message-ID: <20150730104046.GV19282@twins.programming.kicks-ass.net>
Date:	Thu, 30 Jul 2015 12:40:46 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	adrian.hunter@...el.com, x86@...nel.org, hpa@...or.com,
	acme@...radead.org
Subject: Re: [PATCH 1/3] perf/x86/intel/pt: Add new timing packet enables

On Fri, Jul 17, 2015 at 04:34:08PM +0300, Alexander Shishkin wrote:
> +#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN     |	\
> +			RTIT_CTL_DISRETC    |	\
> +			RTIT_CTL_CYCLEACC   |	\
> +			RTIT_CTL_MTC_EN     |	\
> +			RTIT_CTL_MTC_RANGE  |	\
> +			RTIT_CTL_CYC_THRESH |   \
> +			RTIT_CTL_PSB_FREQ)
>  

#define RTIT_CTL_CYC (RTIT_CTL_CYCLEACC   | \
		      RTIT_CTL_CYC_THRESH | \
		      RTIT_CTL_PSB_FREQ)

#define RTIT_CTL_MTC (RTIT_CTL_MTC_EN | \
		      RTIT_CTL_MTC_RANGE)

#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN     | \
			RTIT_CTL_DISRETC    | \
			RTIT_CTL_CYC	    | \
			RTIT_CTL_MTC)

>  static bool pt_event_valid(struct perf_event *event)
>  {
>  	u64 config = event->attr.config;
> +	u64 allowed, requested;
>  
>  	if ((config & PT_CONFIG_MASK) != config)
>  		return false;
>  
> +	if (config &
> +	    (RTIT_CTL_CYCLEACC | RTIT_CTL_CYC_THRESH | RTIT_CTL_PSB_FREQ)) {

	if (config & RTIT_CTL_CYC) {

> +		if (!pt_cap_get(PT_CAP_psb_cyc))
> +			return false;
> +
> +		allowed = pt_cap_get(PT_CAP_psb_periods);
> +		requested = (config & RTIT_CTL_PSB_FREQ) >>
> +			RTIT_CTL_PSB_FREQ_OFFSET;
> +		if (requested && (!(allowed & BIT(requested))))
> +			return false;
> +
> +		allowed = pt_cap_get(PT_CAP_cycle_thresholds);
> +		requested = (config & RTIT_CTL_CYC_THRESH) >>
> +			RTIT_CTL_CYC_THRESH_OFFSET;
> +		if (requested && (!(allowed & BIT(requested))))
> +			return false;
> +	}
> +
> +	if (config & (RTIT_CTL_MTC_EN | RTIT_CTL_MTC_RANGE)) {

	if (config & RTIT_CTL_MTC) {

> +		allowed = pt_cap_get(PT_CAP_mtc_periods);
> +
> +		if (!allowed)
> +			return false;
> +
> +		requested = (config & RTIT_CTL_MTC_RANGE) >>
> +			RTIT_CTL_MTC_RANGE_OFFSET;
> +
> +		if (!(allowed & BIT(requested)))
> +			return false;
> +	}
> +
>  	return true;
>  }

Would that make sense?
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