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powerpc/fadump: Reorganize /sys/kernel/fadump_* sysfs files

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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 backward compatibility a
symlink has been added for every sysfs that has moved to new location.

As the FADump sysfs files are now part of a 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 <sourabhjain@linux.ibm.com>
Tested-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191211160910.21656-4-sourabhjain@linux.ibm.com
This commit is contained in:
Sourabh Jain 2019-12-11 21:39:07 +05:30 committed by Michael Ellerman
parent 9255782f70
commit d418b19f34
2 changed files with 118 additions and 34 deletions
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33
Documentation/ABI/testing/sysfs-kernel-fadump Normal file
View file

@ -0,0 +1,33 @@
What: /sys/kernel/fadump/*
Date: Dec 2019
Contact: linuxppc-dev@lists.ozlabs.org
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: Dec 2019
Contact: linuxppc-dev@lists.ozlabs.org
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: Dec 2019
Contact: linuxppc-dev@lists.ozlabs.org
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: Dec 2019
Contact: linuxppc-dev@lists.ozlabs.org
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.

119
arch/powerpc/kernel/fadump.c
View file

@ -36,6 +36,8 @@ static struct fw_dump fw_dump;
static void __init fadump_reserve_crash_area(u64 base);
struct kobject *fadump_kobj;
#ifndef CONFIG_PRESERVE_FA_DUMP
static DEFINE_MUTEX(fadump_mutex);
struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0 };
@ -1323,9 +1325,9 @@ static void fadump_invalidate_release_mem(void)
fw_dump.ops->fadump_init_mem_struct(&fw_dump);
}
static ssize_t fadump_release_memory_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
static ssize_t release_mem_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int input = -1;
@ -1350,23 +1352,33 @@ static ssize_t fadump_release_memory_store(struct kobject *kobj,
return count;
}
static ssize_t fadump_enabled_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
/* Release the reserved memory and disable the FADump */
static void unregister_fadump(void)
{
fadump_cleanup();
fadump_release_memory(fw_dump.reserve_dump_area_start,
fw_dump.reserve_dump_area_size);
fw_dump.fadump_enabled = 0;
kobject_put(fadump_kobj);
}
static ssize_t enabled_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
}
static ssize_t fadump_register_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
static ssize_t registered_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", fw_dump.dump_registered);
}
static ssize_t fadump_register_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
static ssize_t registered_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret = 0;
int input = -1;
@ -1418,15 +1430,17 @@ static int fadump_region_show(struct seq_file *m, void *private)
return 0;
}
static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
0200, NULL,
fadump_release_memory_store);
static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
0444, fadump_enabled_show,
NULL);
static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
0644, fadump_register_show,
fadump_register_store);
static struct kobj_attribute release_attr = __ATTR_WO(release_mem);
static struct kobj_attribute enable_attr = __ATTR_RO(enabled);
static struct kobj_attribute register_attr = __ATTR_RW(registered);
static struct attribute *fadump_attrs[] = {
&enable_attr.attr,
&register_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(fadump);
DEFINE_SHOW_ATTRIBUTE(fadump_region);
@ -1435,16 +1449,11 @@ static void fadump_init_files(void)
struct dentry *debugfs_file;
int rc = 0;
rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_enabled (%d)\n", rc);
rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_registered (%d)\n", rc);
fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
if (!fadump_kobj) {
pr_err("failed to create fadump kobject\n");
return;
}
debugfs_file = debugfs_create_file("fadump_region", 0444,
powerpc_debugfs_root, NULL,
&fadump_region_fops);
@ -1453,10 +1462,52 @@ static void fadump_init_files(void)
" fadump_region\n");
if (fw_dump.dump_active) {
rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr);
rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
if (rc)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_release_mem (%d)\n", rc);
pr_err("unable to create release_mem sysfs file (%d)\n",
rc);
}
rc = sysfs_create_groups(fadump_kobj, fadump_groups);
if (rc) {
pr_err("sysfs group creation failed (%d), unregistering FADump",
rc);
unregister_fadump();
return;
}
/*
* The FADump sysfs are moved from kernel_kobj to fadump_kobj need to
* create symlink at old location to maintain backward compatibility.
*
* - fadump_enabled -> fadump/enabled
* - fadump_registered -> fadump/registered
* - fadump_release_mem -> fadump/release_mem
*/
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
"enabled", "fadump_enabled");
if (rc) {
pr_err("unable to create fadump_enabled symlink (%d)", rc);
return;
}
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj,
"registered",
"fadump_registered");
if (rc) {
pr_err("unable to create fadump_registered symlink (%d)", rc);
sysfs_remove_link(kernel_kobj, "fadump_enabled");
return;
}
if (fw_dump.dump_active) {
rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj,
fadump_kobj,
"release_mem",
"fadump_release_mem");
if (rc)
pr_err("unable to create fadump_release_mem symlink (%d)",
rc);
}
return;
}