[PATCH v5 3/3] kexec: document new kexec and kdump sysfs ABIs
From: Sourabh Jain <hidden>
Date: 2025-11-17 04:47:46
Also in:
kexec, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Add an ABI document for following kexec and kdump sysfs interface: - /sys/kernel/kexec/loaded - /sys/kernel/kexec/crash_loaded - /sys/kernel/kexec/crash_size - /sys/kernel/kexec/crash_elfcorehdr_size Cc: Aditya Gupta <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baoquan he <redacted> Cc: Dave Young <redacted> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Jiri Bohac <redacted> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mahesh J Salgaonkar <mahesh@linux.ibm.com> Cc: Pingfan Liu <redacted> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Shivang Upadhyay <redacted> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: kexec@lists.infradead.org Signed-off-by: Sourabh Jain <redacted> --- .../ABI/testing/sysfs-kernel-kexec-kdump | 52 +++++++++++++++++++ 1 file changed, 52 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump
index 7e5e528665db..f59051b5d96d 100644
--- a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump
+++ b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump@@ -1,3 +1,55 @@ +What: /sys/kernel/kexec/* +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: + The /sys/kernel/kexec/* directory contains sysfs files + that provide information about the configuration status + of kexec and kdump. + +What: /sys/kernel/kexec/loaded +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a new kernel image has been loaded + into memory using the kexec system call. It shows 1 if + a kexec image is present and ready to boot, or 0 if none + is loaded. +User: kexec tools, kdump service + +What: /sys/kernel/kexec/crash_loaded +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a crash (kdump) kernel is currently + loaded into memory. It shows 1 if a crash kernel has been + successfully loaded for panic handling, or 0 if no crash + kernel is present. +User: Kexec tools, Kdump service + +What: /sys/kernel/kexec/crash_size +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read/write + Shows the amount of memory reserved for loading the crash + (kdump) kernel. It reports the size, in bytes, of the + crash kernel area defined by the crashkernel= parameter. + This interface also allows reducing the crashkernel + reservation by writing a smaller value, and the reclaimed + space is added back to the system RAM. +User: Kdump service + +What: /sys/kernel/kexec/crash_elfcorehdr_size +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates the preferred size of the memory buffer for the + ELF core header used by the crash (kdump) kernel. It defines + how much space is needed to hold metadata about the crashed + system, including CPU and memory information. This information + is used by the user space utility kexec to support updating the + in-kernel kdump image during hotplug operations. +User: Kexec tools + What: /sys/kernel/kexec/crash_cma_ranges Date: Nov 2025 Contact: kexec@lists.infradead.org
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2.51.1