linux-kernel - Re: [PATCH 03/10] coresight: trbe: Add a helper to pad a given buffer area

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Date:   Fri, 30 Jul 2021 15:35:51 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Suzuki K Poulose <suzuki.poulose@....com>,
        linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, coresight@...ts.linaro.org,
        will@...nel.org, catalin.marinas@....com, james.morse@....com,
        mathieu.poirier@...aro.org, mike.leach@...aro.org,
        leo.yan@...aro.org, maz@...nel.org, mark.rutland@....com
Subject: Re: [PATCH 03/10] coresight: trbe: Add a helper to pad a given buffer
 area



On 7/28/21 7:22 PM, Suzuki K Poulose wrote:
> Refactor the helper to pad a given AUX buffer area to allow
> "filling" ignore packets, without moving any handle pointers.
> This will be useful in working around errata, where we may
> have to fill the buffer after a session.
> 
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
>  drivers/hwtracing/coresight/coresight-trbe.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
> index a0168ad204b3..0af644331b99 100644
> --- a/drivers/hwtracing/coresight/coresight-trbe.c
> +++ b/drivers/hwtracing/coresight/coresight-trbe.c
> @@ -228,12 +228,18 @@ static void trbe_stop_and_truncate_event(struct perf_output_handle *handle)
>   * consumed from the user space. The enabled TRBE buffer area is a moving subset of
>   * the allocated perf auxiliary buffer.
>   */
> +
> +static void __trbe_pad_buf(struct trbe_buf *buf, u64 offset, int len)
> +{
> +	memset((void *)buf->trbe_base + offset, ETE_IGNORE_PACKET, len);
> +}
> +
>  static void trbe_pad_buf(struct perf_output_handle *handle, int len)
>  {
>  	struct trbe_buf *buf = etm_perf_sink_config(handle);
>  	u64 head = PERF_IDX2OFF(handle->head, buf);
>  
> -	memset((void *)buf->trbe_base + head, ETE_IGNORE_PACKET, len);
> +	__trbe_pad_buf(buf, head, len);
>  	if (!buf->snapshot)
>  		perf_aux_output_skip(handle, len);
>  }
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>