linux-kernel - Re: [PATCH v2 12/17] coresight: trbe: Add a helper to fetch cpudata from perf handle

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Message-ID: <20211004174239.GB3263478@p14s>
Date:   Mon, 4 Oct 2021 11:42:39 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        maz@...nel.org, catalin.marinas@....com, mark.rutland@....com,
        james.morse@....com, anshuman.khandual@....com, leo.yan@...aro.org,
        mike.leach@...aro.org, will@...nel.org, lcherian@...vell.com,
        coresight@...ts.linaro.org
Subject: Re: [PATCH v2 12/17] coresight: trbe: Add a helper to fetch cpudata
 from perf handle

On Tue, Sep 21, 2021 at 02:41:16PM +0100, Suzuki K Poulose wrote:
> Add a helper to get the CPU specific data for TRBE instance, from
> a given perf handle. This also adds extra checks to make sure that
> the event associated with the handle is "bound" to the CPU and is
> active on the TRBE.
> 
> Cc: Anshuman Khandual <anshuman.khandual@....com>
> Cc: Mike Leach <mike.leach@...aro.org>
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Cc: Leo Yan <leo.yan@...aro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>  drivers/hwtracing/coresight/coresight-trbe.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> index 983dd5039e52..797d978f9fa7 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -268,6 +268,15 @@ static unsigned long trbe_snapshot_offset(struct perf_output_handle *handle)
>  	return buf->nr_pages * PAGE_SIZE;
>  }
>  
> +static inline struct trbe_cpudata *
> +trbe_handle_to_cpudata(struct perf_output_handle *handle)
> +{
> +	struct trbe_buf *buf = etm_perf_sink_config(handle);
> +
> +	BUG_ON(!buf || !buf->cpudata);
> +	return buf->cpudata;
> +}
> +
>  /*
>   * TRBE Limit Calculation
>   *
> @@ -533,8 +542,7 @@ static enum trbe_fault_action trbe_get_fault_act(struct perf_output_handle *hand
>  {
>  	int ec = get_trbe_ec(trbsr);
>  	int bsc = get_trbe_bsc(trbsr);
> -	struct trbe_buf *buf = etm_perf_sink_config(handle);
> -	struct trbe_cpudata *cpudata = buf->cpudata;
> +	struct trbe_cpudata *cpudata = trbe_handle_to_cpudata(handle);

There is two other places where this pattern is present:  is_perf_trbe() and
__trbe_normal_offset().

I have to stop here for today.  More comments tomorrow.

Thanks,
Mathieu

>  
>  	WARN_ON(is_trbe_running(trbsr));
>  	if (is_trbe_trg(trbsr) || is_trbe_abort(trbsr))
> -- 
> 2.24.1
>