Commit 8852c07a authored by Sourabh Jain's avatar Sourabh Jain Committed by Michael Ellerman
Browse files

powerpc/powernv: Move core and fadump_release_opalcore under new kobject 



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: default avatarSourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191211160910.21656-5-sourabhjain@linux.ibm.com
parent d418b19f

Documentation/ABI/testing/sysfs-kernel-fadump_release_opalcore→Documentation/ABI/removed/sysfs-kernel-fadump_release_opalcore

+2 −0
Original line number Diff line number Diff line 
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

Documentation/powerpc/firmware-assisted-dump.rst

+9 −6
Original line number Diff line number Diff line
@@ -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.)

arch/powerpc/platforms/powernv/opal-core.c

+40 −15
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ static LIST_HEAD(opalcore_list); 
static struct opalcore_config *oc_conf;

static const struct opal_mpipl_fadump *opalc_metadata;

static const struct opal_mpipl_fadump *opalc_cpu_metadata;

struct kobject *mpipl_kobj;



/*

 * Set crashing CPU's signal to SIGUSR1. if the kernel is triggered
@@ -428,7 +429,7 @@ static void opalcore_cleanup(void) 
		return;



	/* Remove OPAL core sysfs file */

	sysfs_remove_bin_file(opal_kobj, &opal_core_attr);

	sysfs_remove_bin_file(mpipl_kobj, &opal_core_attr);

	oc_conf->ptload_phdr = NULL;

	oc_conf->ptload_cnt = 0;
@@ -563,7 +564,7 @@ error_out: 
	of_node_put(np);

}



static ssize_t fadump_release_opalcore_store(struct kobject *kobj,

static ssize_t release_core_store(struct kobject *kobj,

				  struct kobj_attribute *attr,

				  const char *buf, size_t count)

{
@@ -589,9 +590,23 @@ static ssize_t fadump_release_opalcore_store(struct kobject *kobj, 
	return count;

}



static struct kobj_attribute opalcore_rel_attr = __ATTR(fadump_release_opalcore,

						0200, NULL,

						fadump_release_opalcore_store);

static struct kobj_attribute opalcore_rel_attr = __ATTR_WO(release_core);



static struct attribute *mpipl_attr[] = {

	&opalcore_rel_attr.attr,

	NULL,

};



static struct bin_attribute *mpipl_bin_attr[] = {

	&opal_core_attr,

	NULL,



};



static struct attribute_group mpipl_group = {

	.attrs = mpipl_attr,

	.bin_attrs =  mpipl_bin_attr,

};



static int __init opalcore_init(void)

{
@@ -609,7 +624,7 @@ 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 +632,28 @@ 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);

	if (rc != 0) {

		pr_err("Failed to export /sys/firmware/opal/core\n");

	rc = sysfs_create_group(mpipl_kobj, &mpipl_group);

	if (rc) {

		pr_err("mpipl sysfs group creation failed (%d)", rc);

		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 = compat_only_sysfs_link_entry_to_kobj(opal_kobj, mpipl_kobj,

						  "core", NULL);

	if (rc) {

		pr_warn("unable to create sysfs file fadump_release_opalcore (%d)\n",

			rc);

		pr_err("unable to create core symlink (%d)\n", rc);

		return rc;

	}



	return 0;

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