[PATCH v4 4/6] powerpc/powernv: move core and fadump_release_opalcore under new kobject

Sourabh Jain
2019-12-06T12:25:07Z

The /sys/firmware/opal/core and /sys/kernel/fadump_release_opalcore sysfs
files are used to export and release the OPAL memory on PowerNV platform.
let's organize them into a new kobject under /sys/firmware/opal/mpipl/
directory.

A symlink is added to maintain the backward compatibility for
/sys/firmware/opal/core sysfs file.

Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---
.../sysfs-kernel-fadump_release_opalcore | 2 ++
.../powerpc/firmware-assisted-dump.rst | 15 +++++----
arch/powerpc/platforms/powernv/opal-core.c | 31 ++++++++++++++-----
3 files changed, 34 insertions(+), 14 deletions(-)
rename Documentation/ABI/{testing => removed}/sysfs-kernel-fadump_release_opalcore (82%)

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..a8d46cd0f4e6 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/firmware/opal/mpipl/release_core.
+
What: /sys/kernel/fadump_release_opalcore
Date: Sep 2019
Contact: linuxppc-dev@lists.ozlabs.org
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index 0455a78486d5..345a3405206e 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -112,13 +112,13 @@ to ensure that crash data is preserved to process later.

-- On OPAL based machines (PowerNV), if the kernel is build with
CONFIG_OPAL_CORE=y, OPAL memory at the time of crash is also
- exported as /sys/firmware/opal/core file. This procfs file is
+ exported as /sys/firmware/opal/mpipl/core file. This procfs file is
helpful in debugging OPAL crashes with GDB. The kernel memory
used for exporting this procfs file can be released by echo'ing
- '1' to /sys/kernel/fadump_release_opalcore node.
+ '1' to /sys/firmware/opal/mpipl/release_core node.

e.g.
- # echo 1 > /sys/kernel/fadump_release_opalcore
+ # echo 1 > /sys/firmware/opal/mpipl/release_core

Implementation details:
-----------------------
@@ -283,14 +283,17 @@ 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/firmware/opal/mpipl/release_core
+
+ /sys/firmware/opal/mpipl/release_core

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
+ used by the kernel to export /sys/firmware/opal/mpipl/core file. To
release this memory, echo '1' to it:

- echo 1 > /sys/kernel/fadump_release_opalcore
+ echo 1 > /sys/firmware/opal/mpipl/release_core

Here is the list of files under powerpc debugfs:
(Assuming debugfs is mounted on /sys/kernel/debug directory.)
diff --git a/arch/powerpc/platforms/powernv/opal-core.c b/arch/powerpc/platforms/powernv/opal-core.c
index ed895d82c048..7fcc092d065e 100644
--- a/arch/powerpc/platforms/powernv/opal-core.c
+++ b/arch/powerpc/platforms/powernv/opal-core.c
@@ -589,7 +589,8 @@ static ssize_t fadump_release_opalcore_store(struct kobject *kobj,
return count;
}

-static struct kobj_attribute opalcore_rel_attr = __ATTR(fadump_release_opalcore,
+struct kobject *mpipl_kobj;
+static struct kobj_attribute opalcore_rel_attr = __ATTR(release_core,
0200, NULL,
fadump_release_opalcore_store);

@@ -609,7 +610,7 @@ static int __init opalcore_init(void)
* then capture the dump.
*/
if (!(is_opalcore_usable())) {
- pr_err("Failed to export /sys/firmware/opal/core\n");
+ pr_err("Failed to export /sys/firmware/opal/mpipl/core\n");
opalcore_cleanup();
return rc;
}
@@ -617,18 +618,32 @@ static int __init opalcore_init(void)
/* Set OPAL core file size */
opal_core_attr.size = oc_conf->opalcore_size;

+ mpipl_kobj = kobject_create_and_add("mpipl", opal_kobj);
+ if (!mpipl_kobj) {
+ pr_err("unable to create mpipl kobject\n");
+ return -ENOMEM;
+ }
+
/* Export OPAL core sysfs file */
- rc = sysfs_create_bin_file(opal_kobj, &opal_core_attr);
+ rc = sysfs_create_bin_file(mpipl_kobj, &opal_core_attr);
if (rc != 0) {
- pr_err("Failed to export /sys/firmware/opal/core\n");
+ pr_err("Failed to export /sys/firmware/opal/mpipl/core\n");
opalcore_cleanup();
return rc;
}
-
- rc = sysfs_create_file(kernel_kobj, &opalcore_rel_attr.attr);
+ /* The /sys/firmware/opal/core is moved to /sys/firmware/opal/mpipl/
+ * directory, need to create symlink at old location to maintain
+ * backward compatibility.
+ */
+ rc = create_sysfs_symlink_entry_to_kobj(opal_kobj, mpipl_kobj,
+ "core", NULL);
+ if (rc) {
+ pr_err("unable to create core symlink (%d)\n", rc);
+ return rc;
+ }
+ rc = sysfs_create_file(mpipl_kobj, &opalcore_rel_attr.attr);
if (rc) {
- pr_warn("unable to create sysfs file fadump_release_opalcore (%d)\n",
- rc);
+ pr_warn("unable to create sysfs file release_core (%d)\n", rc);
}

return 0;
--
2.17.2