[PATCH 0/2] Export kdump crashkernel CMA ranges

[Sourabh Jain]

/sys/kernel/kexec_crash_cma_ranges to export all CMA regions reserved
for the crashkernel to user-space. This enables user-space tools
configuring kdump to determine the amount of memory reserved for the
crashkernel. When CMA is used for crashkernel allocation, tools can use
this information to warn users that attempting to capture user pages
while CMA reservation is active may lead to unreliable or incomplete
dump capture.

While adding documentation for the new sysfs interface, I realized that
there was no ABI document for the existing kexec and kdump sysfs
interfaces, so I added one.

The first patch adds the ABI documentation for the existing kexec and
kdump sysfs interfaces, and the second patch adds the
/sys/kernel/kexec_crash_cma_ranges sysfs interface along with its
corresponding ABI documentation.

*Seeking opinions*
There are already four kexec/kdump sysfs entries under /sys/kernel/,
and this patch series adds one more. Should we consider moving them to
a separate directory, such as /sys/kernel/kexec, to avoid polluting
/sys/kernel/? For backward compatibility, we can create symlinks at
the old locations for sometime and remove them in the future.

Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Baoquan he <bhe at redhat.com>
Cc: Jiri Bohac <jbohac at suse.cz>
Cc: Shivang Upadhyay <shivangu at linux.ibm.com>
Cc: linuxppc-dev at lists.ozlabs.org
Cc: kexec at lists.infradead.org

Sourabh Jain (2):
  Documentation/ABI: add kexec and kdump sysfs interface
  crash: export crashkernel CMA reservation to userspace

 .../ABI/testing/sysfs-kernel-kexec-kdump      | 53 +++++++++++++++++++
 kernel/ksysfs.c                               | 17 ++++++
 2 files changed, 70 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-kernel-kexec-kdump

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2.51.0