Currently, FADump sysfs files are present inside /sys/kernel directory.
But as the number of FADump sysfs file increases it is not a good idea to
push all of them in /sys/kernel directory. It is better to have separate
directory to keep all the FADump sysfs files.
The patch series reorganizes the FADump sysfs files and avail all the
existing FADump sysfs files present inside /sys/kernel into a new
directory /sys/kernel/fadump. Currently, all the FADump sysfs files
are replicated into a new directory to maintain the backward compatibility
and will eventually get removed in future. In addition to this a new FADump
sys interface is added to get the amount of memory reserved by FADump for
saving the crash dump.
Changelog:
v1->v2:
- Move fadump_release_opalcore sysfs to FADump Kobject instead of
replicating.
- Changed the patch order 1,2,3,4 -> 2,1,3,4 (First add the ABI doc for
exisiting sysfs file then replicate them under FADump kobject).
v2->v3:
- Remove the fadump_ prefix from replicated FADump sysfs file names.
Sourabh Jain (4):
Documentation/ABI: add ABI documentation for /sys/kernel/fadump_*
powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files
Documentation/ABI: mark /sys/kernel/fadump_* sysfs files deprecated
powerpc/fadump: sysfs for fadump memory reservation
.../ABI/obsolete/sysfs-kernel-fadump_enabled | 10 ++++
.../obsolete/sysfs-kernel-fadump_registered | 11 ++++
.../obsolete/sysfs-kernel-fadump_release_mem | 11 ++++
.../sysfs-kernel-fadump_release_opalcore | 9 ++++
Documentation/ABI/testing/sysfs-kernel-fadump | 48 +++++++++++++++++
.../powerpc/firmware-assisted-dump.rst | 20 ++++++-
arch/powerpc/kernel/fadump.c | 53 +++++++++++++++++++
arch/powerpc/platforms/powernv/opal-core.c | 10 ++--
8 files changed, 167 insertions(+), 5 deletions(-)
create mode 100644 Documentation/ABI/obsolete/sysfs-kernel-fadump_enabled
create mode 100644 Documentation/ABI/obsolete/sysfs-kernel-fadump_registered
create mode 100644 Documentation/ABI/obsolete/sysfs-kernel-fadump_release_mem
create mode 100644 Documentation/ABI/removed/sysfs-kernel-fadump_release_opalcore
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump
--
2.17.2
Add the missing ABI documentation for the already available FADump
sysfs files.
Signed-off-by: Sourabh Jain <[email protected]>
---
Documentation/ABI/testing/sysfs-kernel-fadump_enabled | 7 +++++++
Documentation/ABI/testing/sysfs-kernel-fadump_registered | 8 ++++++++
Documentation/ABI/testing/sysfs-kernel-fadump_release_mem | 8 ++++++++
.../ABI/testing/sysfs-kernel-fadump_release_opalcore | 7 +++++++
4 files changed, 30 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump_enabled
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump_registered
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump_release_mem
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_enabled b/Documentation/ABI/testing/sysfs-kernel-fadump_enabled
new file mode 100644
index 000000000000..f73632b1c006
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump_enabled
@@ -0,0 +1,7 @@
+What: /sys/kernel/fadump_enabled
+Date: Feb 2012
+Contact: [email protected]
+Description: read only
+ Primarily used to identify whether the FADump is enabled in
+ the kernel or not.
+User: Kdump service
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_registered b/Documentation/ABI/testing/sysfs-kernel-fadump_registered
new file mode 100644
index 000000000000..dcf925e53f0f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump_registered
@@ -0,0 +1,8 @@
+What: /sys/kernel/fadump_registered
+Date: Feb 2012
+Contact: [email protected]
+Description: read/write
+ Helps to control the dump collect feature from userspace.
+ Setting 1 to this file enables the system to collect the
+ dump and 0 to disable it.
+User: Kdump service
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_release_mem b/Documentation/ABI/testing/sysfs-kernel-fadump_release_mem
new file mode 100644
index 000000000000..9c20d64ab48d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump_release_mem
@@ -0,0 +1,8 @@
+What: /sys/kernel/fadump_release_mem
+Date: Feb 2012
+Contact: [email protected]
+Description: write only
+ This is a special sysfs file and only available when
+ the system is booted to capture the vmcore using FADump.
+ It is used to release the memory reserved by FADump to
+ save the crash dump.
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore b/Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore
new file mode 100644
index 000000000000..53313c1d4e7a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore
@@ -0,0 +1,7 @@
+What: /sys/kernel/fadump_release_opalcore
+Date: Sep 2019
+Contact: [email protected]
+Description: write only
+ The sysfs file is available when the system is booted to
+ collect the dump on OPAL based machine. It used to release
+ the memory used to collect the opalcore.
--
2.17.2
The /sys/kernel/fadump_* sysfs files are replicated under
/sys/kernel/fadump/ directory. But we need to keep the old
sysfs files to maintain the backward compatibility.
The sysfs files are scheduled to remove by 2021.
Signed-off-by: Sourabh Jain <[email protected]>
---
.../sysfs-kernel-fadump_enabled | 3 +++
.../sysfs-kernel-fadump_registered | 3 +++
.../sysfs-kernel-fadump_release_mem | 3 +++
.../sysfs-kernel-fadump_release_opalcore | 2 ++
Documentation/powerpc/firmware-assisted-dump.rst | 15 +++++++++++++--
5 files changed, 24 insertions(+), 2 deletions(-)
rename Documentation/ABI/{testing => obsolete}/sysfs-kernel-fadump_enabled (67%)
rename Documentation/ABI/{testing => obsolete}/sysfs-kernel-fadump_registered (72%)
rename Documentation/ABI/{testing => obsolete}/sysfs-kernel-fadump_release_mem (74%)
rename Documentation/ABI/{testing => removed}/sysfs-kernel-fadump_release_opalcore (82%)
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_enabled b/Documentation/ABI/obsolete/sysfs-kernel-fadump_enabled
similarity index 67%
rename from Documentation/ABI/testing/sysfs-kernel-fadump_enabled
rename to Documentation/ABI/obsolete/sysfs-kernel-fadump_enabled
index f73632b1c006..96f49f979e9c 100644
--- a/Documentation/ABI/testing/sysfs-kernel-fadump_enabled
+++ b/Documentation/ABI/obsolete/sysfs-kernel-fadump_enabled
@@ -1,3 +1,6 @@
+This ABI is deprecated and will be removed after 2021. It is replaced
+with /sys/kernel/fadump/enabled.
+
What: /sys/kernel/fadump_enabled
Date: Feb 2012
Contact: [email protected]
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_registered b/Documentation/ABI/obsolete/sysfs-kernel-fadump_registered
similarity index 72%
rename from Documentation/ABI/testing/sysfs-kernel-fadump_registered
rename to Documentation/ABI/obsolete/sysfs-kernel-fadump_registered
index dcf925e53f0f..11ab41c673de 100644
--- a/Documentation/ABI/testing/sysfs-kernel-fadump_registered
+++ b/Documentation/ABI/obsolete/sysfs-kernel-fadump_registered
@@ -1,3 +1,6 @@
+This ABI is deprecated and will be removed after 2021. It is replaced
+with /sys/kernel/fadump/registered.
+
What: /sys/kernel/fadump_registered
Date: Feb 2012
Contact: [email protected]
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_release_mem b/Documentation/ABI/obsolete/sysfs-kernel-fadump_release_mem
similarity index 74%
rename from Documentation/ABI/testing/sysfs-kernel-fadump_release_mem
rename to Documentation/ABI/obsolete/sysfs-kernel-fadump_release_mem
index 9c20d64ab48d..69308b28cb0d 100644
--- a/Documentation/ABI/testing/sysfs-kernel-fadump_release_mem
+++ b/Documentation/ABI/obsolete/sysfs-kernel-fadump_release_mem
@@ -1,3 +1,6 @@
+This ABI is deprecated and will be removed after 2021. It is replaced
+with /sys/kernel/fadump/release_mem.
+
What: /sys/kernel/fadump_release_mem
Date: Feb 2012
Contact: [email protected]
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore b/Documentation/ABI/removed/sysfs-kernel-fadump_release_opalcore
similarity index 82%
rename from Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore
rename to Documentation/ABI/removed/sysfs-kernel-fadump_release_opalcore
index 53313c1d4e7a..fe42956a3f41 100644
--- a/Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore
+++ b/Documentation/ABI/removed/sysfs-kernel-fadump_release_opalcore
@@ -1,3 +1,5 @@
+This ABI is moved to /sys/kernel/fadump/release_opalcore.
+
What: /sys/kernel/fadump_release_opalcore
Date: Sep 2019
Contact: [email protected]
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index 0455a78486d5..fc7b06408cea 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -283,14 +283,25 @@ Here is the list of files under kernel sysfs:
enhanced to use this interface to release the memory reserved for
dump and continue without 2nd reboot.
- /sys/kernel/fadump_release_opalcore
+Note: /sys/kernel/fadump_release_opalcore sysfs has moved to
+ /sys/kernel/fadump/release_opalcore.
+
+ /sys/kernel/fadump/release_opalcore
This file is available only on OPAL based machines when FADump is
active during capture kernel. This is used to release the memory
used by the kernel to export /sys/firmware/opal/core file. To
release this memory, echo '1' to it:
- echo 1 > /sys/kernel/fadump_release_opalcore
+ echo 1 > /sys/kernel/fadump/release_opalcore
+
+Note: The following FADump sysfs files are deprecated.
+
+ Deprecated Alternative
+ --------------------------------------------------------------------
+ /sys/kernel/fadump_enabled /sys/kernel/fadump/enabled
+ /sys/kernel/fadump_registered /sys/kernel/fadump/registered
+ /sys/kernel/fadump_release_mem /sys/kernel/fadump/release_mem
Here is the list of files under powerpc debugfs:
(Assuming debugfs is mounted on /sys/kernel/debug directory.)
--
2.17.2
Add a sys interface to allow querying the memory reserved by FADump for
saving the crash dump.
Also added Documentation/ABI for the new sysfs file.
Signed-off-by: Sourabh Jain <[email protected]>
---
Documentation/ABI/testing/sysfs-kernel-fadump | 7 +++++++
Documentation/powerpc/firmware-assisted-dump.rst | 5 +++++
arch/powerpc/kernel/fadump.c | 15 +++++++++++++++
3 files changed, 27 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
index a77f1a5ba389..c1d87c787b9a 100644
--- a/Documentation/ABI/testing/sysfs-kernel-fadump
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump
@@ -39,3 +39,10 @@ Description: write only
The sysfs file is available when the system is booted to
collect the dump on OPAL based machine. It used to release
the memory used to collect the opalcore.
+
+What: /sys/kernel/fadump/mem_reserved
+Date: Nov 2019
+Contact: [email protected]
+Description: read only
+ Provide information about the amount of memory reserved by
+ FADump to save the crash dump in bytes.
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index fc7b06408cea..01c3c9461cd5 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -268,6 +268,11 @@ 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 a9591def0c84..2ed80f7b2652 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1357,6 +1357,13 @@ 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)
@@ -1440,6 +1447,10 @@ static struct kobj_attribute enable_attr = __ATTR(enabled,
static struct kobj_attribute register_attr = __ATTR(registered,
0644, fadump_register_show,
fadump_register_store);
+static struct kobj_attribute mem_reserved_attr = __ATTR(mem_reserved,
+ 0444, fadump_mem_reserved_show,
+ NULL);
+
DEFINE_SHOW_ATTRIBUTE(fadump_region);
@@ -1496,6 +1507,10 @@ static void fadump_init_files(void)
pr_err("unable to create release_mem sysfs file (%d)\n",
rc);
}
+ rc = sysfs_create_file(fadump_kobj, &mem_reserved_attr.attr);
+ if (rc)
+ pr_err("unable to create mem_reserved sysfs file (%d)\n",
+ rc);
return;
}
--
2.17.2
As the number of FADump sysfs files increases it is hard to manage all of
them inside /sys/kernel directory. It's better to have all the FADump
related sysfs files in a dedicated directory /sys/kernel/fadump. But in
order to maintain the backward compatibility the /sys/kernel/fadump_*
sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
removed in future.
As the FADump sysfs files are now part of dedicated directory there is no
need to prefix their name with fadump_, hence sysfs file names are also
updated. For example fadump_enabled sysfs file is now referred as enabled.
Also consolidate ABI documentation for all the FADump sysfs files in a
single file Documentation/ABI/testing/sysfs-kernel-fadump.
Signed-off-by: Sourabh Jain <[email protected]>
---
Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++
arch/powerpc/platforms/powernv/opal-core.c | 10 +++--
3 files changed, 86 insertions(+), 3 deletions(-)
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..a77f1a5ba389
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump
@@ -0,0 +1,41 @@
+What: /sys/kernel/fadump/*
+Date: Nov 2019
+Contact: [email protected]
+Description:
+ The /sys/kernel/fadump/* is a collection of FADump sysfs
+ file provide information about the configuration status
+ of Firmware Assisted Dump (FADump).
+
+What: /sys/kernel/fadump/enabled
+Date: Nov 2019
+Contact: [email protected]
+Description: read only
+ Primarily used to identify whether the FADump is enabled in
+ the kernel or not.
+User: Kdump service
+
+What: /sys/kernel/fadump/registered
+Date: Nov 2019
+Contact: [email protected]
+Description: read/write
+ Helps to control the dump collect feature from userspace.
+ Setting 1 to this file enables the system to collect the
+ dump and 0 to disable it.
+User: Kdump service
+
+What: /sys/kernel/fadump/release_mem
+Date: Nov 2019
+Contact: [email protected]
+Description: write only
+ This is a special sysfs file and only available when
+ the system is booted to capture the vmcore using FADump.
+ It is used to release the memory reserved by FADump to
+ save the crash dump.
+
+What: /sys/kernel/fadump/release_opalcore
+Date: Nov 2019
+Contact: [email protected]
+Description: write only
+ The sysfs file is available when the system is booted to
+ collect the dump on OPAL based machine. It used to release
+ the memory used to collect the opalcore.
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index ed59855430b9..a9591def0c84 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
return 0;
}
+struct kobject *fadump_kobj;
+EXPORT_SYMBOL_GPL(fadump_kobj);
+
static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
0200, NULL,
fadump_release_memory_store);
@@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
0644, fadump_register_show,
fadump_register_store);
+static struct kobj_attribute release_attr = __ATTR(release_mem,
+ 0200, NULL,
+ fadump_release_memory_store);
+static struct kobj_attribute enable_attr = __ATTR(enabled,
+ 0444, fadump_enabled_show,
+ NULL);
+static struct kobj_attribute register_attr = __ATTR(registered,
+ 0644, fadump_register_show,
+ fadump_register_store);
+
DEFINE_SHOW_ATTRIBUTE(fadump_region);
static void fadump_init_files(void)
@@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
struct dentry *debugfs_file;
int rc = 0;
+ fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
+ if (!fadump_kobj) {
+ pr_err("failed to create fadump kobject\n");
+ return;
+ }
rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
@@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_release_mem (%d)\n", rc);
}
+ /* Replicating the following sysfs attributes under FADump kobject.
+ *
+ * - fadump_enabled -> enabled
+ * - fadump_registered -> registered
+ * - fadump_release_mem -> release_mem
+ */
+ rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
+ if (rc)
+ pr_err("unable to create enabled sysfs file (%d)\n",
+ rc);
+ rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
+ if (rc)
+ pr_err("unable to create registered sysfs file (%d)\n",
+ rc);
+ if (fw_dump.dump_active) {
+ rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
+ if (rc)
+ pr_err("unable to create release_mem sysfs file (%d)\n",
+ rc);
+ }
return;
}
diff --git a/arch/powerpc/platforms/powernv/opal-core.c b/arch/powerpc/platforms/powernv/opal-core.c
index ed895d82c048..b001e2242909 100644
--- a/arch/powerpc/platforms/powernv/opal-core.c
+++ b/arch/powerpc/platforms/powernv/opal-core.c
@@ -589,7 +589,7 @@ static ssize_t fadump_release_opalcore_store(struct kobject *kobj,
return count;
}
-static struct kobj_attribute opalcore_rel_attr = __ATTR(fadump_release_opalcore,
+static struct kobj_attribute opalcore_rel_attr = __ATTR(release_opalcore,
0200, NULL,
fadump_release_opalcore_store);
@@ -625,9 +625,13 @@ static int __init opalcore_init(void)
return rc;
}
- rc = sysfs_create_file(kernel_kobj, &opalcore_rel_attr.attr);
+ /*
+ * Originally fadump_release_opalcore sysfs was part of kernel_kobj
+ * later moved to fadump_kobj and renamed to release_opalcore.
+ */
+ rc = sysfs_create_file(fadump_kobj, &opalcore_rel_attr.attr);
if (rc) {
- pr_warn("unable to create sysfs file fadump_release_opalcore (%d)\n",
+ pr_warn("unable to create sysfs file release_opalcore (%d)\n",
rc);
}
--
2.17.2
On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote:
> As the number of FADump sysfs files increases it is hard to manage all of
> them inside /sys/kernel directory. It's better to have all the FADump
> related sysfs files in a dedicated directory /sys/kernel/fadump. But in
> order to maintain the backward compatibility the /sys/kernel/fadump_*
> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
> removed in future.
>
> As the FADump sysfs files are now part of dedicated directory there is no
> need to prefix their name with fadump_, hence sysfs file names are also
> updated. For example fadump_enabled sysfs file is now referred as enabled.
>
> Also consolidate ABI documentation for all the FADump sysfs files in a
> single file Documentation/ABI/testing/sysfs-kernel-fadump.
>
> Signed-off-by: Sourabh Jain <[email protected]>
> ---
> Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
> arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++
> arch/powerpc/platforms/powernv/opal-core.c | 10 +++--
> 3 files changed, 86 insertions(+), 3 deletions(-)
> 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..a77f1a5ba389
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
> @@ -0,0 +1,41 @@
> +What: /sys/kernel/fadump/*
> +Date: Nov 2019
> +Contact: [email protected]
> +Description:
> + The /sys/kernel/fadump/* is a collection of FADump sysfs
> + file provide information about the configuration status
> + of Firmware Assisted Dump (FADump).
> +
> +What: /sys/kernel/fadump/enabled
> +Date: Nov 2019
> +Contact: [email protected]
> +Description: read only
> + Primarily used to identify whether the FADump is enabled in
> + the kernel or not.
> +User: Kdump service
> +
> +What: /sys/kernel/fadump/registered
> +Date: Nov 2019
> +Contact: [email protected]
> +Description: read/write
> + Helps to control the dump collect feature from userspace.
> + Setting 1 to this file enables the system to collect the
> + dump and 0 to disable it.
> +User: Kdump service
> +
> +What: /sys/kernel/fadump/release_mem
> +Date: Nov 2019
> +Contact: [email protected]
> +Description: write only
> + This is a special sysfs file and only available when
> + the system is booted to capture the vmcore using FADump.
> + It is used to release the memory reserved by FADump to
> + save the crash dump.
> +
> +What: /sys/kernel/fadump/release_opalcore
> +Date: Nov 2019
> +Contact: [email protected]
> +Description: write only
> + The sysfs file is available when the system is booted to
> + collect the dump on OPAL based machine. It used to release
> + the memory used to collect the opalcore.
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index ed59855430b9..a9591def0c84 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
> return 0;
> }
>
> +struct kobject *fadump_kobj;
> +EXPORT_SYMBOL_GPL(fadump_kobj);
> +
> static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
> 0200, NULL,
> fadump_release_memory_store);
> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
> 0644, fadump_register_show,
> fadump_register_store);
>
> +static struct kobj_attribute release_attr = __ATTR(release_mem,
> + 0200, NULL,
> + fadump_release_memory_store);
> +static struct kobj_attribute enable_attr = __ATTR(enabled,
> + 0444, fadump_enabled_show,
> + NULL);
> +static struct kobj_attribute register_attr = __ATTR(registered,
> + 0644, fadump_register_show,
> + fadump_register_store);
> +
> DEFINE_SHOW_ATTRIBUTE(fadump_region);
>
> static void fadump_init_files(void)
> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
> struct dentry *debugfs_file;
> int rc = 0;
>
> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
> + if (!fadump_kobj) {
> + pr_err("failed to create fadump kobject\n");
> + return;
> + }
> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
> if (rc)
> printk(KERN_ERR "fadump: unable to create sysfs file"
> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
> printk(KERN_ERR "fadump: unable to create sysfs file"
> " fadump_release_mem (%d)\n", rc);
> }
> + /* Replicating the following sysfs attributes under FADump kobject.
> + *
> + * - fadump_enabled -> enabled
> + * - fadump_registered -> registered
> + * - fadump_release_mem -> release_mem
> + */
> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
> + if (rc)
> + pr_err("unable to create enabled sysfs file (%d)\n",
> + rc);
> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
> + if (rc)
> + pr_err("unable to create registered sysfs file (%d)\n",
> + rc);
> + if (fw_dump.dump_active) {
> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
> + if (rc)
> + pr_err("unable to create release_mem sysfs file (%d)\n",
> + rc);
> + }
> return;
> }
Hello,
wouldn't it make more sense to create the files in the new location and
add a symlink at the old location?
Also your error messages aren't really readeable. Without the fadump_
prefix it's not clear what's going on here. Perhaps quoting the file
name and saying fadump somewhere in the message would be useful.
Thanks
Michal
On 11/9/19 6:29 PM, Michal Suchánek wrote:
> On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote:
>> As the number of FADump sysfs files increases it is hard to manage all of
>> them inside /sys/kernel directory. It's better to have all the FADump
>> related sysfs files in a dedicated directory /sys/kernel/fadump. But in
>> order to maintain the backward compatibility the /sys/kernel/fadump_*
>> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
>> removed in future.
>>
>> As the FADump sysfs files are now part of dedicated directory there is no
>> need to prefix their name with fadump_, hence sysfs file names are also
>> updated. For example fadump_enabled sysfs file is now referred as enabled.
>>
>> Also consolidate ABI documentation for all the FADump sysfs files in a
>> single file Documentation/ABI/testing/sysfs-kernel-fadump.
>>
>> Signed-off-by: Sourabh Jain <[email protected]>
>> ---
>> Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
>> arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++
>> arch/powerpc/platforms/powernv/opal-core.c | 10 +++--
>> 3 files changed, 86 insertions(+), 3 deletions(-)
>> 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..a77f1a5ba389
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
>> @@ -0,0 +1,41 @@
>> +What: /sys/kernel/fadump/*
>> +Date: Nov 2019
>> +Contact: [email protected]
>> +Description:
>> + The /sys/kernel/fadump/* is a collection of FADump sysfs
>> + file provide information about the configuration status
>> + of Firmware Assisted Dump (FADump).
>> +
>> +What: /sys/kernel/fadump/enabled
>> +Date: Nov 2019
>> +Contact: [email protected]
>> +Description: read only
>> + Primarily used to identify whether the FADump is enabled in
>> + the kernel or not.
>> +User: Kdump service
>> +
>> +What: /sys/kernel/fadump/registered
>> +Date: Nov 2019
>> +Contact: [email protected]
>> +Description: read/write
>> + Helps to control the dump collect feature from userspace.
>> + Setting 1 to this file enables the system to collect the
>> + dump and 0 to disable it.
>> +User: Kdump service
>> +
>> +What: /sys/kernel/fadump/release_mem
>> +Date: Nov 2019
>> +Contact: [email protected]
>> +Description: write only
>> + This is a special sysfs file and only available when
>> + the system is booted to capture the vmcore using FADump.
>> + It is used to release the memory reserved by FADump to
>> + save the crash dump.
>> +
>> +What: /sys/kernel/fadump/release_opalcore
>> +Date: Nov 2019
>> +Contact: [email protected]
>> +Description: write only
>> + The sysfs file is available when the system is booted to
>> + collect the dump on OPAL based machine. It used to release
>> + the memory used to collect the opalcore.
>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>> index ed59855430b9..a9591def0c84 100644
>> --- a/arch/powerpc/kernel/fadump.c
>> +++ b/arch/powerpc/kernel/fadump.c
>> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
>> return 0;
>> }
>>
>> +struct kobject *fadump_kobj;
>> +EXPORT_SYMBOL_GPL(fadump_kobj);
>> +
>> static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
>> 0200, NULL,
>> fadump_release_memory_store);
>> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
>> 0644, fadump_register_show,
>> fadump_register_store);
>>
>> +static struct kobj_attribute release_attr = __ATTR(release_mem,
>> + 0200, NULL,
>> + fadump_release_memory_store);
>> +static struct kobj_attribute enable_attr = __ATTR(enabled,
>> + 0444, fadump_enabled_show,
>> + NULL);
>> +static struct kobj_attribute register_attr = __ATTR(registered,
>> + 0644, fadump_register_show,
>> + fadump_register_store);
>> +
>> DEFINE_SHOW_ATTRIBUTE(fadump_region);
>>
>> static void fadump_init_files(void)
>> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
>> struct dentry *debugfs_file;
>> int rc = 0;
>>
>> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
>> + if (!fadump_kobj) {
>> + pr_err("failed to create fadump kobject\n");
>> + return;
>> + }
>> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
>> if (rc)
>> printk(KERN_ERR "fadump: unable to create sysfs file"
>> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
>> printk(KERN_ERR "fadump: unable to create sysfs file"
>> " fadump_release_mem (%d)\n", rc);
>> }
>> + /* Replicating the following sysfs attributes under FADump kobject.
>> + *
>> + * - fadump_enabled -> enabled
>> + * - fadump_registered -> registered
>> + * - fadump_release_mem -> release_mem
>> + */
>> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
>> + if (rc)
>> + pr_err("unable to create enabled sysfs file (%d)\n",
>> + rc);
>> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
>> + if (rc)
>> + pr_err("unable to create registered sysfs file (%d)\n",
>> + rc);
>> + if (fw_dump.dump_active) {
>> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
>> + if (rc)
>> + pr_err("unable to create release_mem sysfs file (%d)\n",
>> + rc);
>> + }
>> return;
>> }
> Hello,
>
I’m so sorry for taking this long to write you back.
> wouldn't it make more sense to create the files in the new location and
> add a symlink at the old location?
There are APIs which allow to create a symlink for an entire kobject but
I did not find a way to create symlink of an individual sysfs file.
Do you have any approach in mind to achieve the same?
> Also your error messages aren't really readeable. Without the fadump_
> prefix it's not clear what's going on here. Perhaps quoting the file
> name and saying fadump somewhere in the message would be useful.
The pr_err function will prefix the error message with fadump: string.
I think that will solve the above issue.
Thanks,
Sourabh Jain
Hi Sourabh,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on v5.4-rc8 next-20191122]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Sourabh-Jain/reorganize-and-add-FADump-sysfs-files/20191110-091753
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-rhel-kconfig (attached as .config)
compiler: powerpc64le-linux-gcc (GCC) 7.4.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.4.0 make.cross ARCH=powerpc
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <[email protected]>
All errors (new ones prefixed by >>):
arch/powerpc/platforms/powernv/opal-core.c: In function 'opalcore_init':
>> arch/powerpc/platforms/powernv/opal-core.c:632:25: error: 'fadump_kobj' undeclared (first use in this function); did you mean 'fadump_ops'?
rc = sysfs_create_file(fadump_kobj, &opalcore_rel_attr.attr);
^~~~~~~~~~~
fadump_ops
arch/powerpc/platforms/powernv/opal-core.c:632:25: note: each undeclared identifier is reported only once for each function it appears in
vim +632 arch/powerpc/platforms/powernv/opal-core.c
591
592 static struct kobj_attribute opalcore_rel_attr = __ATTR(release_opalcore,
593 0200, NULL,
594 fadump_release_opalcore_store);
595
596 static int __init opalcore_init(void)
597 {
598 int rc = -1;
599
600 opalcore_config_init();
601
602 if (oc_conf == NULL)
603 return rc;
604
605 create_opalcore();
606
607 /*
608 * If oc_conf->opalcorebuf= is set in the 2nd kernel,
609 * then capture the dump.
610 */
611 if (!(is_opalcore_usable())) {
612 pr_err("Failed to export /sys/firmware/opal/core\n");
613 opalcore_cleanup();
614 return rc;
615 }
616
617 /* Set OPAL core file size */
618 opal_core_attr.size = oc_conf->opalcore_size;
619
620 /* Export OPAL core sysfs file */
621 rc = sysfs_create_bin_file(opal_kobj, &opal_core_attr);
622 if (rc != 0) {
623 pr_err("Failed to export /sys/firmware/opal/core\n");
624 opalcore_cleanup();
625 return rc;
626 }
627
628 /*
629 * Originally fadump_release_opalcore sysfs was part of kernel_kobj
630 * later moved to fadump_kobj and renamed to release_opalcore.
631 */
> 632 rc = sysfs_create_file(fadump_kobj, &opalcore_rel_attr.attr);
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/[email protected] Intel Corporation
On Sat, Nov 16, 2019 at 08:07:29PM +0530, Sourabh Jain wrote:
>
>
> On 11/9/19 6:29 PM, Michal Suchánek wrote:
> > On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote:
> >> As the number of FADump sysfs files increases it is hard to manage all of
> >> them inside /sys/kernel directory. It's better to have all the FADump
> >> related sysfs files in a dedicated directory /sys/kernel/fadump. But in
> >> order to maintain the backward compatibility the /sys/kernel/fadump_*
> >> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
> >> removed in future.
> >>
> >> As the FADump sysfs files are now part of dedicated directory there is no
> >> need to prefix their name with fadump_, hence sysfs file names are also
> >> updated. For example fadump_enabled sysfs file is now referred as enabled.
> >>
> >> Also consolidate ABI documentation for all the FADump sysfs files in a
> >> single file Documentation/ABI/testing/sysfs-kernel-fadump.
> >>
> >> Signed-off-by: Sourabh Jain <[email protected]>
> >> ---
> >> Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
> >> arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++
> >> arch/powerpc/platforms/powernv/opal-core.c | 10 +++--
> >> 3 files changed, 86 insertions(+), 3 deletions(-)
> >> 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..a77f1a5ba389
> >> --- /dev/null
> >> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
> >> @@ -0,0 +1,41 @@
> >> +What: /sys/kernel/fadump/*
> >> +Date: Nov 2019
> >> +Contact: [email protected]
> >> +Description:
> >> + The /sys/kernel/fadump/* is a collection of FADump sysfs
> >> + file provide information about the configuration status
> >> + of Firmware Assisted Dump (FADump).
> >> +
> >> +What: /sys/kernel/fadump/enabled
> >> +Date: Nov 2019
> >> +Contact: [email protected]
> >> +Description: read only
> >> + Primarily used to identify whether the FADump is enabled in
> >> + the kernel or not.
> >> +User: Kdump service
> >> +
> >> +What: /sys/kernel/fadump/registered
> >> +Date: Nov 2019
> >> +Contact: [email protected]
> >> +Description: read/write
> >> + Helps to control the dump collect feature from userspace.
> >> + Setting 1 to this file enables the system to collect the
> >> + dump and 0 to disable it.
> >> +User: Kdump service
> >> +
> >> +What: /sys/kernel/fadump/release_mem
> >> +Date: Nov 2019
> >> +Contact: [email protected]
> >> +Description: write only
> >> + This is a special sysfs file and only available when
> >> + the system is booted to capture the vmcore using FADump.
> >> + It is used to release the memory reserved by FADump to
> >> + save the crash dump.
> >> +
> >> +What: /sys/kernel/fadump/release_opalcore
> >> +Date: Nov 2019
> >> +Contact: [email protected]
> >> +Description: write only
> >> + The sysfs file is available when the system is booted to
> >> + collect the dump on OPAL based machine. It used to release
> >> + the memory used to collect the opalcore.
> >> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> >> index ed59855430b9..a9591def0c84 100644
> >> --- a/arch/powerpc/kernel/fadump.c
> >> +++ b/arch/powerpc/kernel/fadump.c
> >> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
> >> return 0;
> >> }
> >>
> >> +struct kobject *fadump_kobj;
> >> +EXPORT_SYMBOL_GPL(fadump_kobj);
> >> +
> >> static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
> >> 0200, NULL,
> >> fadump_release_memory_store);
> >> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
> >> 0644, fadump_register_show,
> >> fadump_register_store);
> >>
> >> +static struct kobj_attribute release_attr = __ATTR(release_mem,
> >> + 0200, NULL,
> >> + fadump_release_memory_store);
> >> +static struct kobj_attribute enable_attr = __ATTR(enabled,
> >> + 0444, fadump_enabled_show,
> >> + NULL);
> >> +static struct kobj_attribute register_attr = __ATTR(registered,
> >> + 0644, fadump_register_show,
> >> + fadump_register_store);
> >> +
> >> DEFINE_SHOW_ATTRIBUTE(fadump_region);
> >>
> >> static void fadump_init_files(void)
> >> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
> >> struct dentry *debugfs_file;
> >> int rc = 0;
> >>
> >> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
> >> + if (!fadump_kobj) {
> >> + pr_err("failed to create fadump kobject\n");
> >> + return;
> >> + }
> >> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
> >> if (rc)
> >> printk(KERN_ERR "fadump: unable to create sysfs file"
> >> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
> >> printk(KERN_ERR "fadump: unable to create sysfs file"
> >> " fadump_release_mem (%d)\n", rc);
> >> }
> >> + /* Replicating the following sysfs attributes under FADump kobject.
> >> + *
> >> + * - fadump_enabled -> enabled
> >> + * - fadump_registered -> registered
> >> + * - fadump_release_mem -> release_mem
> >> + */
> >> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
> >> + if (rc)
> >> + pr_err("unable to create enabled sysfs file (%d)\n",
> >> + rc);
> >> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
> >> + if (rc)
> >> + pr_err("unable to create registered sysfs file (%d)\n",
> >> + rc);
> >> + if (fw_dump.dump_active) {
> >> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
> >> + if (rc)
> >> + pr_err("unable to create release_mem sysfs file (%d)\n",
> >> + rc);
> >> + }
> >> return;
> >> }
> > Hello,
> >
>
> I’m so sorry for taking this long to write you back.
>
> > wouldn't it make more sense to create the files in the new location and
> > add a symlink at the old location?
>
> There are APIs which allow to create a symlink for an entire kobject but
> I did not find a way to create symlink of an individual sysfs file.
>
> Do you have any approach in mind to achieve the same?
There is at least one example of plain symlink:
find /sys -type l -xtype f
/sys/kernel/security/evm
If there is no interface to do one sanely duplicationg the files is
better than nothing.
Thanks
Michal
On 11/25/19 12:10 AM, Michal Suchánek wrote:
> On Sat, Nov 16, 2019 at 08:07:29PM +0530, Sourabh Jain wrote:
>>
>>
>> On 11/9/19 6:29 PM, Michal Suchánek wrote:
>>> On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote:
>>>> As the number of FADump sysfs files increases it is hard to manage all of
>>>> them inside /sys/kernel directory. It's better to have all the FADump
>>>> related sysfs files in a dedicated directory /sys/kernel/fadump. But in
>>>> order to maintain the backward compatibility the /sys/kernel/fadump_*
>>>> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
>>>> removed in future.
>>>>
>>>> As the FADump sysfs files are now part of dedicated directory there is no
>>>> need to prefix their name with fadump_, hence sysfs file names are also
>>>> updated. For example fadump_enabled sysfs file is now referred as enabled.
>>>>
>>>> Also consolidate ABI documentation for all the FADump sysfs files in a
>>>> single file Documentation/ABI/testing/sysfs-kernel-fadump.
>>>>
>>>> Signed-off-by: Sourabh Jain <[email protected]>
>>>> ---
>>>> Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
>>>> arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++
>>>> arch/powerpc/platforms/powernv/opal-core.c | 10 +++--
>>>> 3 files changed, 86 insertions(+), 3 deletions(-)
>>>> 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..a77f1a5ba389
>>>> --- /dev/null
>>>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
>>>> @@ -0,0 +1,41 @@
>>>> +What: /sys/kernel/fadump/*
>>>> +Date: Nov 2019
>>>> +Contact: [email protected]
>>>> +Description:
>>>> + The /sys/kernel/fadump/* is a collection of FADump sysfs
>>>> + file provide information about the configuration status
>>>> + of Firmware Assisted Dump (FADump).
>>>> +
>>>> +What: /sys/kernel/fadump/enabled
>>>> +Date: Nov 2019
>>>> +Contact: [email protected]
>>>> +Description: read only
>>>> + Primarily used to identify whether the FADump is enabled in
>>>> + the kernel or not.
>>>> +User: Kdump service
>>>> +
>>>> +What: /sys/kernel/fadump/registered
>>>> +Date: Nov 2019
>>>> +Contact: [email protected]
>>>> +Description: read/write
>>>> + Helps to control the dump collect feature from userspace.
>>>> + Setting 1 to this file enables the system to collect the
>>>> + dump and 0 to disable it.
>>>> +User: Kdump service
>>>> +
>>>> +What: /sys/kernel/fadump/release_mem
>>>> +Date: Nov 2019
>>>> +Contact: [email protected]
>>>> +Description: write only
>>>> + This is a special sysfs file and only available when
>>>> + the system is booted to capture the vmcore using FADump.
>>>> + It is used to release the memory reserved by FADump to
>>>> + save the crash dump.
>>>> +
>>>> +What: /sys/kernel/fadump/release_opalcore
>>>> +Date: Nov 2019
>>>> +Contact: [email protected]
>>>> +Description: write only
>>>> + The sysfs file is available when the system is booted to
>>>> + collect the dump on OPAL based machine. It used to release
>>>> + the memory used to collect the opalcore.
>>>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>>>> index ed59855430b9..a9591def0c84 100644
>>>> --- a/arch/powerpc/kernel/fadump.c
>>>> +++ b/arch/powerpc/kernel/fadump.c
>>>> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
>>>> return 0;
>>>> }
>>>>
>>>> +struct kobject *fadump_kobj;
>>>> +EXPORT_SYMBOL_GPL(fadump_kobj);
>>>> +
>>>> static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
>>>> 0200, NULL,
>>>> fadump_release_memory_store);
>>>> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
>>>> 0644, fadump_register_show,
>>>> fadump_register_store);
>>>>
>>>> +static struct kobj_attribute release_attr = __ATTR(release_mem,
>>>> + 0200, NULL,
>>>> + fadump_release_memory_store);
>>>> +static struct kobj_attribute enable_attr = __ATTR(enabled,
>>>> + 0444, fadump_enabled_show,
>>>> + NULL);
>>>> +static struct kobj_attribute register_attr = __ATTR(registered,
>>>> + 0644, fadump_register_show,
>>>> + fadump_register_store);
>>>> +
>>>> DEFINE_SHOW_ATTRIBUTE(fadump_region);
>>>>
>>>> static void fadump_init_files(void)
>>>> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
>>>> struct dentry *debugfs_file;
>>>> int rc = 0;
>>>>
>>>> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
>>>> + if (!fadump_kobj) {
>>>> + pr_err("failed to create fadump kobject\n");
>>>> + return;
>>>> + }
>>>> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
>>>> if (rc)
>>>> printk(KERN_ERR "fadump: unable to create sysfs file"
>>>> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
>>>> printk(KERN_ERR "fadump: unable to create sysfs file"
>>>> " fadump_release_mem (%d)\n", rc);
>>>> }
>>>> + /* Replicating the following sysfs attributes under FADump kobject.
>>>> + *
>>>> + * - fadump_enabled -> enabled
>>>> + * - fadump_registered -> registered
>>>> + * - fadump_release_mem -> release_mem
>>>> + */
>>>> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create enabled sysfs file (%d)\n",
>>>> + rc);
>>>> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create registered sysfs file (%d)\n",
>>>> + rc);
>>>> + if (fw_dump.dump_active) {
>>>> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create release_mem sysfs file (%d)\n",
>>>> + rc);
>>>> + }
>>>> return;
>>>> }
>>> Hello,
>>>
>>
>> I’m so sorry for taking this long to write you back.
>>
>>> wouldn't it make more sense to create the files in the new location and
>>> add a symlink at the old location?
>>
>> There are APIs which allow to create a symlink for an entire kobject but
>> I did not find a way to create symlink of an individual sysfs file.
>>
>> Do you have any approach in mind to achieve the same?
>
> There is at least one example of plain symlink:
>
> find /sys -type l -xtype f
> /sys/kernel/security/evm
Yes, there are APIs available in debugfs and securityfs that allow creatinga symlink of sysfs files. But I did not find a generic API at sysfs level tocreate symlink.
Let's wait for others to put in their view on this. Meanwhile, I'll start
exploring how we can replace the older FADump sysfs files with symlink.
Thanks,
Sourabh Jain
>>>> DEFINE_SHOW_ATTRIBUTE(fadump_region);
>>>>
>>>> static void fadump_init_files(void)
>>>> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
>>>> struct dentry *debugfs_file;
>>>> int rc = 0;
>>>>
>>>> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
>>>> + if (!fadump_kobj) {
>>>> + pr_err("failed to create fadump kobject\n");
>>>> + return;
>>>> + }
>>>> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
>>>> if (rc)
>>>> printk(KERN_ERR "fadump: unable to create sysfs file"
>>>> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
>>>> printk(KERN_ERR "fadump: unable to create sysfs file"
>>>> " fadump_release_mem (%d)\n", rc);
>>>> }
>>>> + /* Replicating the following sysfs attributes under FADump kobject.
>>>> + *
>>>> + * - fadump_enabled -> enabled
>>>> + * - fadump_registered -> registered
>>>> + * - fadump_release_mem -> release_mem
>>>> + */
>>>> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create enabled sysfs file (%d)\n",
>>>> + rc);
>>>> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create registered sysfs file (%d)\n",
>>>> + rc);
>>>> + if (fw_dump.dump_active) {
>>>> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
>>>> + if (rc)
>>>> + pr_err("unable to create release_mem sysfs file (%d)\n",
>>>> + rc);
>>>> + }
>>>> return;
>>>> }
>>> Hello,
>>>
>>
>> I’m so sorry for taking this long to write you back.
>>
>>> wouldn't it make more sense to create the files in the new location and
>>> add a symlink at the old location?
>>
>> There are APIs which allow to create a symlink for an entire kobject but
>> I did not find a way to create symlink of an individual sysfs file.
>>
>> Do you have any approach in mind to achieve the same?
>
> There is at least one example of plain symlink:
>
> find /sys -type l -xtype f
> /sys/kernel/security/evm
>
> If there is no interface to do one sanely duplicationg the files is
> better than nothing.
Hello Michal,
I found a function (__compat_only_sysfs_link_entry_to_kobj) that adds a symlink
to a kobject.
But the problem is __compat_only_sysfs_link_entry_to_kobj function keeps the
symlink file name similar to sysfs file and has no option to change it.
We can't use the __compat_only_sysfs_link_entry_to_kobj function directly because
our symlink file name must be different from the target file name.
fadump_enabled -> fadump/enabled
But the good thing is we can tweak the __compat_only_sysfs_link_entry_to_kobj
function and allow the caller to change the sysmlink file name.
So I am writing a separate patch that adds a wrapper function around the __compat_only_sysfs_link_entry_to_kobj function which will allow to have a custom symlink file name.
Thanks,
Sourabh Jain