powerpc/fadump: sysfs for fadump memory reservation

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 <sourabhjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191211160910.21656-7-sourabhjain@linux.ibm.com
This commit is contained in:
Sourabh Jain 2019-12-11 21:39:10 +05:30 committed by Michael Ellerman
parent 3f5f1f22ef
commit d8e73458f3
3 changed files with 21 additions and 0 deletions

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@ -31,3 +31,10 @@ Description: write only
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/mem_reserved
Date: Dec 2019
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only
Provide information about the amount of memory reserved by
FADump to save the crash dump in bytes.

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@ -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

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@ -1369,6 +1369,13 @@ static ssize_t enabled_show(struct kobject *kobj,
return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
}
static ssize_t 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 registered_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
@ -1433,10 +1440,12 @@ static int fadump_region_show(struct seq_file *m, void *private)
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 kobj_attribute mem_reserved_attr = __ATTR_RO(mem_reserved);
static struct attribute *fadump_attrs[] = {
&enable_attr.attr,
&register_attr.attr,
&mem_reserved_attr.attr,
NULL,
};