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: <43612930-6c17-4c6f-bc4e-954bcfd7977e@arm.com>
Date: Wed, 9 Oct 2024 10:50:29 +0100
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Mao Jinlong <quic_jinlmao@...cinc.com>, Mike Leach
 <mike.leach@...aro.org>, James Clark <james.clark@....com>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v4 RESEND 2/3] coresight: Add support to get static id for
 system trace sources

On 10/09/2024 11:01, Mao Jinlong wrote:
> Dynamic trace id was introduced in coresight subsystem, so trace id is
> allocated dynamically. However, some hardware ATB source has static trace
> id and it cannot be changed via software programming. For such source,
> it can call coresight_get_static_trace_id to get the fixed trace id from
> device node and pass id to coresight_trace_id_get_static_system_id to
> reserve the id.
> 
> Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>

This patch is technically doing two different things :

1. Support for reading the static traceid from the firmware. (users of 
which comes later in Dummy)

2. Support for allocating a "specific" traceid for system sources.


Both the names are a bit similar and could be confusing.

For (1), I don't think we need to add a helper like that. See my 
comments below, and drop all of that from here this patch.


> ---
>   .../hwtracing/coresight/coresight-platform.c  | 26 +++++++++++++
>   .../hwtracing/coresight/coresight-trace-id.c  | 38 ++++++++++++++-----
>   .../hwtracing/coresight/coresight-trace-id.h  |  9 +++++
>   include/linux/coresight.h                     |  1 +
>   4 files changed, 64 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 64e171eaad82..703abf0fa3f9 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -183,6 +183,18 @@ static int of_coresight_get_cpu(struct device *dev)
>   	return cpu;
>   }
>   
> +/*
> + * of_coresight_get_trace_id: Get the atid of a source device.
> + *
> + * Returns 0 on success.
> + */
> +static int of_coresight_get_static_trace_id(struct device *dev, u32 *id)
> +{
> +
> +	return of_property_read_u32(dev->of_node, "arm,static-trace-id", id);
> +}
> +
> +
>   /*
>    * of_coresight_parse_endpoint : Parse the given output endpoint @ep
>    * and fill the connection information in @pdata->out_conns
> @@ -317,6 +329,11 @@ static inline int of_coresight_get_cpu(struct device *dev)
>   {
>   	return -ENODEV;
>   }
> +
> +static inline int of_coresight_get_static_trace_id(struct device *dev, u32 *id)
> +{
> +	return -ENODEV;
> +}
>   #endif


>   
>   #ifdef CONFIG_ACPI
> @@ -796,6 +813,15 @@ int coresight_get_cpu(struct device *dev)
>   }
>   EXPORT_SYMBOL_GPL(coresight_get_cpu);
>   
> +int coresight_get_static_trace_id(struct device *dev, u32 *id)
> +{
> +	if (!is_of_node(dev->fwnode))
> +		return -EINVAL;
> +
> +	return of_coresight_get_static_trace_id(dev, id);

Please could we not directly use :

fwnode_property_read_u32(dev_fwnode(dev), "arm,static-trace-id", 
&traceid) in the dummy driver ?

The rest looks fine to me.

Suzuki


> +}
> +EXPORT_SYMBOL_GPL(coresight_get_static_trace_id);
> +
>   struct coresight_platform_data *
>   coresight_get_platform_data(struct device *dev)
>   {
> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
> index af5b4ef59cea..ca3c3de4683e 100644
> --- a/drivers/hwtracing/coresight/coresight-trace-id.c
> +++ b/drivers/hwtracing/coresight/coresight-trace-id.c
> @@ -11,6 +11,12 @@
>   
>   #include "coresight-trace-id.h"
>   
> +enum trace_id_flags {
> +	TRACE_ID_ANY = 0x0,
> +	TRACE_ID_PREFER_ODD = 0x1,
> +	TRACE_ID_REQ_STATIC = 0x2,
> +};
> +
>   /* Default trace ID map. Used on systems that don't require per sink mappings */
>   static struct coresight_trace_id_map id_map_default;
>   
> @@ -80,16 +86,19 @@ static int coresight_trace_id_find_odd_id(struct coresight_trace_id_map *id_map)
>    * Otherwise allocate next available ID.
>    */
>   static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map,
> -					   int preferred_id, bool prefer_odd_id)
> +					   int preferred_id, unsigned int flags)
>   {
>   	int id = 0;
>   
>   	/* for backwards compatibility, cpu IDs may use preferred value */
> -	if (IS_VALID_CS_TRACE_ID(preferred_id) &&
> -	    !test_bit(preferred_id, id_map->used_ids)) {
> -		id = preferred_id;
> -		goto trace_id_allocated;
> -	} else if (prefer_odd_id) {
> +	if (IS_VALID_CS_TRACE_ID(preferred_id)) {
> +		if (!test_bit(preferred_id, id_map->used_ids)) {
> +			id = preferred_id;
> +			goto trace_id_allocated;
> +		} else if (WARN((flags & TRACE_ID_REQ_STATIC), "Trace ID %d is used.\n",
> +					preferred_id))
> +			return -EINVAL;
> +	} else if (flags & TRACE_ID_PREFER_ODD) {
>   	/* may use odd ids to avoid preferred legacy cpu IDs */
>   		id = coresight_trace_id_find_odd_id(id_map);
>   		if (id)
> @@ -175,7 +184,7 @@ static int coresight_trace_id_map_get_cpu_id(int cpu, struct coresight_trace_id_
>   	 */
>   	id = coresight_trace_id_alloc_new_id(id_map,
>   					     CORESIGHT_LEGACY_CPU_TRACE_ID(cpu),
> -					     false);
> +					     TRACE_ID_ANY);
>   	if (!IS_VALID_CS_TRACE_ID(id))
>   		goto get_cpu_id_out_unlock;
>   
> @@ -222,14 +231,15 @@ static void coresight_trace_id_map_put_cpu_id(int cpu, struct coresight_trace_id
>   	DUMP_ID_MAP(id_map);
>   }
>   
> -static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map)
> +static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map,
> +					int preferred_id, unsigned int traceid_flags)
>   {
>   	unsigned long flags;
>   	int id;
>   
>   	spin_lock_irqsave(&id_map_lock, flags);
>   	/* prefer odd IDs for system components to avoid legacy CPU IDS */
> -	id = coresight_trace_id_alloc_new_id(id_map, 0, true);
> +	id = coresight_trace_id_alloc_new_id(id_map, preferred_id, traceid_flags);
>   	spin_unlock_irqrestore(&id_map_lock, flags);
>   
>   	DUMP_ID(id);
> @@ -271,10 +281,18 @@ EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id);
>   
>   int coresight_trace_id_get_system_id(void)
>   {
> -	return coresight_trace_id_map_get_system_id(&id_map_default);
> +	return coresight_trace_id_map_get_system_id(&id_map_default, 0,
> +			TRACE_ID_PREFER_ODD);
>   }
>   EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
>   
> +int coresight_trace_id_get_static_system_id(int trace_id)
> +{
> +	return coresight_trace_id_map_get_system_id(&id_map_default,
> +			trace_id, TRACE_ID_REQ_STATIC);
> +}
> +EXPORT_SYMBOL_GPL(coresight_trace_id_get_static_system_id);
> +
>   void coresight_trace_id_put_system_id(int id)
>   {
>   	coresight_trace_id_map_put_system_id(&id_map_default, id);
> diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h
> index 3797777d367e..ca2fdf31c835 100644
> --- a/drivers/hwtracing/coresight/coresight-trace-id.h
> +++ b/drivers/hwtracing/coresight/coresight-trace-id.h
> @@ -122,6 +122,15 @@ int coresight_trace_id_read_cpu_id(int cpu);
>    */
>   int coresight_trace_id_get_system_id(void);
>   
> +/**
> + * Allocate a CoreSight static trace ID for a system component.
> + *
> + * Used to allocate static IDs for system trace sources such as dummy source.
> + *
> + * return: Trace ID or -EINVAL if allocation is impossible.
> + */
> +int coresight_trace_id_get_static_system_id(int id);
> +
>   /**
>    * Release an allocated system trace ID.
>    *
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index f09ace92176e..2cdc0b1cd536 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -643,6 +643,7 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
>   void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
>   
>   extern int coresight_get_cpu(struct device *dev);
> +extern int coresight_get_static_trace_id(struct device *dev, u32 *id);
>   
>   struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
>   struct coresight_connection *


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ