[PATCH] powerpc/fadump: sysfs for fadump memory reservation

[Mahesh Jagannath Salgaonkar]

On 8/6/19 8:42 AM, Sourabh Jain wrote:
> Add a sys interface to allow querying the memory reserved by fadump
> for saving the crash dump.
> 
> Signed-off-by: Sourabh Jain <sourabhjain at linux.ibm.com>

Looks good to me.

Reviewed-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

Thanks,
-Mahesh.

> ---
>  Documentation/powerpc/firmware-assisted-dump.rst |  5 +++++
>  arch/powerpc/kernel/fadump.c                     | 14 ++++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
> index 9ca12830a48e..4a7f6dc556f5 100644
> --- a/Documentation/powerpc/firmware-assisted-dump.rst
> +++ b/Documentation/powerpc/firmware-assisted-dump.rst
> @@ -222,6 +222,11 @@ Here is the list of files under kernel sysfs:
>      be handled and vmcore will not be captured. This interface can be
>      easily integrated with kdump service start/stop.
> 
> +/sys/kernel/fadump_mem_reserved
> +
> +   This is used to display the memory reserved by fadump for saving the
> +   crash dump.
> +
>   /sys/kernel/fadump_release_mem
>      This file is available only when fadump is active during
>      second kernel. This is used to release the reserved memory
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 4eab97292cc2..70d49013ebec 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -1514,6 +1514,13 @@ static ssize_t fadump_enabled_show(struct kobject *kobj,
>  	return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
>  }
> 
> +static ssize_t fadump_mem_reserved_show(struct kobject *kobj,
> +					struct kobj_attribute *attr,
> +					char *buf)
> +{
> +	return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
> +}
> +
>  static ssize_t fadump_register_show(struct kobject *kobj,
>  					struct kobj_attribute *attr,
>  					char *buf)
> @@ -1632,6 +1639,9 @@ static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
>  static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
>  						0644, fadump_register_show,
>  						fadump_register_store);
> +static struct kobj_attribute fadump_mem_reserved_attr =
> +			__ATTR(fadump_mem_reserved, 0444,
> +			fadump_mem_reserved_show, NULL);
> 
>  DEFINE_SHOW_ATTRIBUTE(fadump_region);
> 
> @@ -1663,6 +1673,10 @@ static void fadump_init_files(void)
>  			printk(KERN_ERR "fadump: unable to create sysfs file"
>  				" fadump_release_mem (%d)\n", rc);
>  	}
> +	rc = sysfs_create_file(kernel_kobj, &fadump_mem_reserved_attr.attr);
> +	if (rc)
> +		pr_err("unable to create sysfs file fadump_mem_reserved (%d)\n",
> +			rc);
>  	return;
>  }
>