linux-kernel - Re: [PATCH v2 02/13] coresight: trace-id: update CoreSight core to use Trace ID API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1019b931-4d0d-ecea-c170-29e3899acd9b@arm.com>
Date:   Tue, 19 Jul 2022 18:36:18 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Mike Leach <mike.leach@...aro.org>, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     mathieu.poirier@...aro.org, peterz@...radead.org, mingo@...hat.com,
        acme@...nel.org, linux-perf-users@...r.kernel.org,
        leo.yan@...aro.org, quic_jinlmao@...cinc.com
Subject: Re: [PATCH v2 02/13] coresight: trace-id: update CoreSight core to
 use Trace ID API

Hi Mike

On 04/07/2022 09:11, Mike Leach wrote:
> Initialises the default trace ID map.
> 
> This will be used by all source drivers to be allocated their trace IDs.

As per previous patch, we may not need an explicit call from here.

> 
> The checks for sources to have unique IDs has been removed - this is now
> guaranteed by the ID allocation mechanisms, and inappropriate where
> multiple ID maps are in use in larger systems
> 

And this looks like a candidate for a separate patch, as the sources do
not use the new API yet ? Once they do, in the following patches, we
could remove this code.


All said, this patch could be renamed and moved to the bottom of the 
series, with :

  "coresight: Remove obsolete trace-id uniqueness checks"

Otherwise, looks good to me.



> Signed-off-by: Mike Leach <mike.leach@...aro.org>
> ---
>   drivers/hwtracing/coresight/coresight-core.c | 49 ++------------------
>   1 file changed, 4 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 1edfec1e9d18..be69e05fde1f 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -22,6 +22,7 @@
>   #include "coresight-etm-perf.h"
>   #include "coresight-priv.h"
>   #include "coresight-syscfg.h"
> +#include "coresight-trace-id.h"
>   
>   static DEFINE_MUTEX(coresight_mutex);
>   static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
> @@ -84,45 +85,6 @@ struct coresight_device *coresight_get_percpu_sink(int cpu)
>   }
>   EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
>   
> -static int coresight_id_match(struct device *dev, void *data)
> -{
> -	int trace_id, i_trace_id;
> -	struct coresight_device *csdev, *i_csdev;
> -
> -	csdev = data;
> -	i_csdev = to_coresight_device(dev);
> -
> -	/*
> -	 * No need to care about oneself and components that are not
> -	 * sources or not enabled
> -	 */
> -	if (i_csdev == csdev || !i_csdev->enable ||
> -	    i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
> -		return 0;
> -
> -	/* Get the source ID for both components */
> -	trace_id = source_ops(csdev)->trace_id(csdev);
> -	i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
> -
> -	/* All you need is one */
> -	if (trace_id == i_trace_id)
> -		return 1;
> -
> -	return 0;
> -}
> -
> -static int coresight_source_is_unique(struct coresight_device *csdev)
> -{
> -	int trace_id = source_ops(csdev)->trace_id(csdev);
> -
> -	/* this shouldn't happen */
> -	if (trace_id < 0)
> -		return 0;
> -
> -	return !bus_for_each_dev(&coresight_bustype, NULL,
> -				 csdev, coresight_id_match);
> -}
> -
>   static int coresight_find_link_inport(struct coresight_device *csdev,
>   				      struct coresight_device *parent)
>   {
> @@ -431,12 +393,6 @@ static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
>   {
>   	int ret;
>   
> -	if (!coresight_source_is_unique(csdev)) {
> -		dev_warn(&csdev->dev, "traceID %d not unique\n",
> -			 source_ops(csdev)->trace_id(csdev));
> -		return -EINVAL;
> -	}
> -
>   	if (!csdev->enable) {
>   		if (source_ops(csdev)->enable) {
>   			ret = coresight_control_assoc_ectdev(csdev, true);
> @@ -1775,6 +1731,9 @@ static int __init coresight_init(void)
>   	if (ret)
>   		goto exit_bus_unregister;
>   
> +	/* initialise the default trace ID map */
> +	coresight_trace_id_init_default_map();
> +
>   	/* initialise the coresight syscfg API */
>   	ret = cscfg_init();
>   	if (!ret)


Suzuki