2019-08-08 10:09:39

by Sourabh Jain

Subject: [PATCH v2] powerpc/fadump: sysfs for fadump memory reservation

Add a sys interface to allow querying the memory reserved by
fadump for saving the crash dump.

Add an ABI doc entry for new sysfs interface.
- /sys/kernel/fadump_mem_reserved

Signed-off-by: Sourabh Jain <[email protected]>
---
v1 -> v2:
- Added ABI doc for new sysfs interface.
---

Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
Documentation/powerpc/firmware-assisted-dump.rst | 5 +++++
arch/powerpc/kernel/fadump.c | 14 ++++++++++++++
3 files changed, 25 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump

diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
new file mode 100644
index 000000000000..003e2f025dcb
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump
@@ -0,0 +1,6 @@
+What: /sys/kernel/fadump_mem_reserved
+Date: August 2019
+Contact: [email protected]
+Description: read only
+ Provide information about the amount of memory
+ reserved by fadump to saving the crash dump.
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index 9ca12830a48e..a5dfb20d4dc3 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..cd373d1d4b82 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;
}

--
2.17.2

2019-08-08 11:19:11

by Hari Bathini

Subject: Re: [PATCH v2] powerpc/fadump: sysfs for fadump memory reservation

On 08/08/19 3:38 PM, Sourabh Jain wrote:
> Add a sys interface to allow querying the memory reserved by
> fadump for saving the crash dump.
>
> Add an ABI doc entry for new sysfs interface.
> - /sys/kernel/fadump_mem_reserved
>
> Signed-off-by: Sourabh Jain <[email protected]>
> ---
> v1 -> v2:
> - Added ABI doc for new sysfs interface.
> ---
>
> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
> Documentation/powerpc/firmware-assisted-dump.rst | 5 +++++
> arch/powerpc/kernel/fadump.c | 14 ++++++++++++++
> 3 files changed, 25 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump
>
> diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
> new file mode 100644
> index 000000000000..003e2f025dcb
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
> @@ -0,0 +1,6 @@
> +What: /sys/kernel/fadump_mem_reserved
> +Date: August 2019
> +Contact: [email protected]
> +Description: read only
> + Provide information about the amount of memory
> + reserved by fadump to saving the crash dump.

s/to saving/to save/

Rest looks good..

Thanks
Hari