linux-kernel - Re: [PATCH 3/3] remoteproc: Add coredump sysfs attribute

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Date:   Thu, 23 Apr 2020 14:47:56 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Rishabh Bhatnagar <rishabhb@...eaurora.org>
Cc:     linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        bjorn.andersson@...aro.org, ohad@...ery.com, tsoni@...eaurora.org,
        psodagud@...eaurora.org, sidgup@...eaurora.org
Subject: Re: [PATCH 3/3] remoteproc: Add coredump sysfs attribute

On Thu, Apr 16, 2020 at 11:38:32AM -0700, Rishabh Bhatnagar wrote:
> Add coredump sysfs attribute to configure the type of memory dump.
> User can select between default or inline coredump functionality.
> Also coredump collection can be disabled through this interface.
> This functionality can be configured differently for different
> remote processors.
> This provides an option to dynamically configure the dump type
> based on userpsace capability.
> 
> Signed-off-by: Rishabh Bhatnagar <rishabhb@...eaurora.org>
> ---
>  drivers/remoteproc/remoteproc_sysfs.c | 57 +++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
> index 7f8536b..d112664 100644
> --- a/drivers/remoteproc/remoteproc_sysfs.c
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -9,6 +9,62 @@
>  
>  #define to_rproc(d) container_of(d, struct rproc, dev)
>  
> +/*
> + * A coredump-configuration-to-string lookup table, for exposing a
> + * human readable configuration via sysfs. Always keep in sync with
> + * enum rproc_coredump_conf
> + */
> +static const char * const rproc_coredump_str[] = {
> +	[COREDUMP_DEFAULT]	= "default",
> +	[COREDUMP_INLINE]	= "inline",
> +	[COREDUMP_DISABLED]	= "disabled",
> +};
> +
> +/* Expose the current coredump configuration via sysfs */
> +static ssize_t coredump_show(struct device *dev, struct device_attribute *attr,
> +			      char *buf)
> +{
> +	struct rproc *rproc = to_rproc(dev);
> +
> +	return sprintf(buf, "%s\n", rproc_coredump_str[rproc->coredump_conf]);
> +}
> +
> +/* Change the coredump configuration via sysfs */
> +static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
> +			       const char *buf, size_t count)
> +{
> +	struct rproc *rproc = to_rproc(dev);
> +	int err;
> +
> +	err = mutex_lock_interruptible(&rproc->lock);
> +	if (err) {
> +		dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err);
> +		return -EINVAL;
> +	}
> +
> +	if (rproc->state == RPROC_CRASHED) {
> +		dev_err(dev, "can't change coredump configuration\n");
> +		err = -EBUSY;
> +		goto out;
> +	}
> +
> +	if (sysfs_streq(buf, "disable"))
> +		rproc->coredump_conf = COREDUMP_DISABLED;
> +	else if (sysfs_streq(buf, "inline"))
> +		rproc->coredump_conf = COREDUMP_INLINE;
> +	else if (sysfs_streq(buf, "default"))
> +		rproc->coredump_conf = COREDUMP_DEFAULT;
> +	else {
> +		dev_err(dev, "Invalid coredump configuration\n");
> +		err = -EINVAL;
> +	}
> +out:
> +	mutex_unlock(&rproc->lock);
> +
> +	return err ? err : count;
> +}
> +static DEVICE_ATTR_RW(coredump);
> +
>  /* Expose the loaded / running firmware name via sysfs */
>  static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
>  			  char *buf)
> @@ -127,6 +183,7 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
>  	&dev_attr_firmware.attr,
>  	&dev_attr_state.attr,
>  	&dev_attr_name.attr,
> +	&dev_attr_coredump.attr,

This new entry needs to be documented in [1].  The set also needs to be rebased
on rproc-next.

Thanks,
Mathieu

[1]. https://elixir.bootlin.com/linux/v5.7-rc2/source/Documentation/ABI/testing/sysfs-class-remoteproc

>  	NULL
>  };
>  
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project