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Thu, 6 Nov 2025 04:51:32 +0000 (GMT) From: Sourabh Jain To: linux-kernel@vger.kernel.org Cc: Sourabh Jain , Aditya Gupta , Andrew Morton , Baoquan he , Dave Young , Hari Bathini , Jiri Bohac , Madhavan Srinivasan , Mahesh J Salgaonkar , Pingfan Liu , "Ritesh Harjani (IBM)" , Shivang Upadhyay , Vivek Goyal , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org Subject: [PATCH v2 4/5] kexec: document new kexec and kdump sysfs ABIs Date: Thu, 6 Nov 2025 10:21:06 +0530 Message-ID: <20251106045107.17813-5-sourabhjain@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251106045107.17813-1-sourabhjain@linux.ibm.com> References: <20251106045107.17813-1-sourabhjain@linux.ibm.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAxMDAyMSBTYWx0ZWRfX3RNIKR1bDv7z NvHOR8vbsi3hU2sVnRUY39IyPbRgOsQfK1xLBexK4u84isxJLAdmaIMZ2WSL/gyMqGPeLVBjcU5 zFL6gWATChXfEKZUPdkz77DcTP/+LK7eBAnO41EJUAwL5IP/Wkh7XiWaL9WbaooYhugFRVvvRn1 7RGaUY8N+rvSPZ/tU68x05Mjku7WIowkRXkL6IL6GHf+tQ/NDQPkDzeYG1BSZfrYDt2Jtq3iV+R Xp9NOQLQIy+UsRwFD2hoUnSxEEmSQzuc06arrfuIxzo+isZYjcdI95Oy+QWfrEXgMfqKmZNdw3F 12FhxeCe+125zFZEQGZ4wP1ngq7EQjr6uee0GH2dYQx/9U1PmSFAtI54jSopakvgiOYcS30ibSK b0qiM81rgMjDwVHOezXocQhKjhYkUg== X-Proofpoint-GUID: ZGIfCtVhTxvyie3433xx49AZvwfxYAsc X-Authority-Analysis: v=2.4 cv=OdCVzxTY c=1 sm=1 tr=0 ts=690c295e cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=Z4Rwk6OoAAAA:8 a=20KFwNOVAAAA:8 a=pGLkceISAAAA:8 a=voM4FWlXAAAA:8 a=JfrnYn6hAAAA:8 a=C7Xb30-FUlXqnvbFlGcA:9 a=HkZW87K1Qel5hWWM3VKY:22 a=IC2XNlieTeVoXbcui8wp:22 a=1CNFftbPRP8L7MoqJWF3:22 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: Wiqnz9uKC6LAu5BDpfjljqEFDbdsY3p0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-05_09,2025-11-03_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 adultscore=0 spamscore=0 suspectscore=0 impostorscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511010021 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 Cc: Andrew Morton Cc: Baoquan he Cc: Dave Young Cc: Hari Bathini Cc: Jiri Bohac Cc: Madhavan Srinivasan Cc: Mahesh J Salgaonkar Cc: Pingfan Liu Cc: Ritesh Harjani (IBM) Cc: Shivang Upadhyay Cc: Vivek Goyal Cc: linuxppc-dev@lists.ozlabs.org Cc: kexec@lists.infradead.org Signed-off-by: Sourabh Jain --- .../ABI/testing/sysfs-kernel-kexec-kdump | 51 +++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-kexec-kdump diff --git a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump new file mode 100644 index 000000000000..00c00f380fea --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump @@ -0,0 +1,51 @@ +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 -- 2.51.0