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Fri, 14 Nov 2025 05:15:37 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F10272004B; Fri, 14 Nov 2025 05:15:35 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 84ABD20040; Fri, 14 Nov 2025 05:15:32 +0000 (GMT) Received: from li-4f5ba44c-27d4-11b2-a85c-a08f5b49eada.ibm.com.com (unknown [9.124.211.127]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 14 Nov 2025 05:15:32 +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 v4 4/5] kexec: document new kexec and kdump sysfs ABIs Date: Fri, 14 Nov 2025 10:45:03 +0530 Message-ID: <20251114051504.614937-5-sourabhjain@linux.ibm.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251114051504.614937-1-sourabhjain@linux.ibm.com> References: <20251114051504.614937-1-sourabhjain@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Y4Z0HWr1SrHzHy5SOcYxvgW9ijMU1kOo X-Authority-Analysis: v=2.4 cv=E9nAZKdl c=1 sm=1 tr=0 ts=6916bafe cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==: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-Spam-Details-Enc: AW1haW4tMjUxMTEzMDE3OSBTYWx0ZWRfX66rOMSOMECLQ WB+Yj2RaAKZwCWwd5fFsqQ1PDglrTwG+xBC3dtk7PNo8UXuTyuAujmqrxrn/e35UOV9U+VFG+Z4 cfAIXD83djUxDrtnpiH0Ke0HAJR5H76QQ+GSaxSI3EXwvdkw3OGvG5S+ho9pqXljepNirkzdRVu 5QNsr0/B3KJgkFJHqmt589HaMPzlEqu/SpBejgJXRJfzZCHTINbG/y56RmHStlQ7c+qIvWdDx9P f8xtuCHkAI18CxUh2Gtbi0Nn7unixDFrnE1LIqaFrU3u3uFJ1NPPvHbzKVFx9tV3TgDg2St8U+t Bg6T4SWst/Igd+6t0CtFxb5QhNmKar1C51GLrljOSJTnFVKmVGidP1Ut2VQMjsZciRl6x27kD6A 7bfce34cJK5I4ZJ+6pD7Rw6qcoheMw== X-Proofpoint-GUID: QcdouxTxhNkTuFpwKb7wixN58y4V_Y6G 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=2025-11-13_07,2025-11-13_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 impostorscore=0 malwarescore=0 clxscore=1015 priorityscore=1501 adultscore=0 lowpriorityscore=0 bulkscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511130179 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 -- 2.51.1