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Thu, 20 Aug 2026 10:13:56 +0000 (GMT) Received: from b315lp23.lnxne.boe (unknown [9.87.84.240]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 20 Aug 2026 10:13:55 +0000 (GMT) From: Joseph Cathcart To: linux-s390@vger.kernel.org, kexec@lists.infradead.org Cc: eoin.mcnamara@ibm.com, iii@de.ibm.com, Joseph Cathcart Subject: [PATCH v2] kexec-tools/s390: add --reuseinitrd support Date: Thu, 20 Aug 2026 12:13:50 +0200 Message-ID: <20260820101350.4413-1-josephc@linux.ibm.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=MthiLWae c=1 sm=1 tr=0 ts=6a86d36b cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=G9HDwhCky0EsxXTtCDsA:9 X-Proofpoint-ORIG-GUID: 2eRslKVqPphDN6aNAetcuRIAEXOjpOYx X-Proofpoint-GUID: 2eRslKVqPphDN6aNAetcuRIAEXOjpOYx X-Proofpoint-Spam-Info: AW1haW4tMjYwODIwMDA3MyBTYWx0ZWRfXzxRoQ0WXUXsz M8uiDzEURrkEouzSi8jWQ+p+5oX/5pv4E0mTCmvextEdty0FRJJbRmKz8G3UANO1SGakl4//hZi Ea+8L1PRcqDZ3+N0eX4rHXi0B24pIZY= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODIwMDA3MyBTYWx0ZWRfX6e4xZyQ2Pfsr ryKBE6be4x+6YS4gGBQKfsggNxLsyfT2GITYtL7+kukw5QDfny/48c0y4E+0ks1ak1qnsYS6PYG cQCWxVsLV473gNcTsOjcUjlQ9X4I63oN2hA27z1lETg22Us6QzKVazPrG3gPslfQ9PmvCCqY5fG LSnAw7xMwwvb1XXjI/oXNAIHlVVfaK+UEBW5hlJnaNLs1OU2jhy6c7iVxxX3+GERx9zj5THc3TK +Ccn9DIXz7Tc4k6P8oaBv9qVOhmcKsWybX9r9n2yJZiPkAlVXjEyc1AcI71TOCU38MaXJlQQH8A wqf1kNFQ7WhJijCvqk/1pQcPSbOW1/QNUdvEIe/0y6XPqNu+E3d3OuQSD+rrI0a+l8yWAl3fzRH zIdKHntBvhyYSYoX5QDm+RVg14YG416cFuOfVErwXZsyHT+XpkVP2rGppPZqEu/XiTPPOl0Wt76 gIQK/KQmGpU79hhxeUg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-19_06,2026-08-19_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 bulkscore=0 phishscore=0 clxscore=1015 spamscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608200073 Currently, the --reuseinitrd param is not supported on s390. This prevents testing kexec in environments such as virtme-ng, which by default does not store the initrd on disk. When --reuseinitrd is specified, fetch retained initrd memory range from /proc/iomem and fill new kernel parmarea directly with retained initrd base and size, rather than memory range of a new ramdisk. Add die() cases for when user uses --reuseinitrd: - in addition to --ramdisk or --initrd - while booting a crash kernel. - with kexec-file-load syscall (default syscall) - and no initrd entry is found in /proc/iomem Signed-off-by: Joseph Cathcart --- kexec/arch/s390/Makefile | 2 ++ kexec/arch/s390/kexec-image.c | 15 ++++++++++++++- kexec/arch/s390/kexec-s390.c | 14 ++++++++++++++ kexec/arch/s390/kexec-s390.h | 2 ++ 4 files changed, 32 insertions(+), 1 deletion(-) diff --git a/kexec/arch/s390/Makefile b/kexec/arch/s390/Makefile index fab3e68..17f9dc8 100644 --- a/kexec/arch/s390/Makefile +++ b/kexec/arch/s390/Makefile @@ -6,6 +6,8 @@ s390_KEXEC_SRCS += kexec/arch/s390/kexec-image.c s390_KEXEC_SRCS += kexec/arch/s390/kexec-elf-rel-s390.c s390_KEXEC_SRCS += kexec/arch/s390/crashdump-s390.c +s390_ARCH_REUSE_INITRD = + dist += kexec/arch/s390/Makefile $(s390_KEXEC_SRCS) \ kexec/arch/s390/kexec-s390.h \ kexec/arch/s390/include/arch/options.h diff --git a/kexec/arch/s390/kexec-image.c b/kexec/arch/s390/kexec-image.c index 69aaf96..a9e5442 100644 --- a/kexec/arch/s390/kexec-image.c +++ b/kexec/arch/s390/kexec-image.c @@ -78,6 +78,10 @@ int image_s390_load_file(int argc, char **argv, struct kexec_info *info) } } + if (reuse_initrd) + die("--reuseinitrd not supported with --kexec-file-syscall. " + "Please use --kexec-syscall\n"); + if (ramdisk) { info->initrd_fd = open(ramdisk, O_RDONLY); if (info->initrd_fd == -1) { @@ -104,7 +108,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf, char *rd_buffer; const char *ramdisk; off_t ramdisk_len; - unsigned int ramdisk_origin; + unsigned long long ramdisk_origin; int opt, ret = -1; if (info->file_mode) @@ -137,6 +141,12 @@ image_s390_load(int argc, char **argv, const char *kernel_buf, } } + if (ramdisk && reuse_initrd) + die("Can't specify --ramdisk or --initrd with --reuseinitrd\n"); + + if (reuse_initrd && (info->kexec_flags & KEXEC_ON_CRASH)) + die("Can't specify --reuseinitrd while booting a crash kernel\n"); + if (info->kexec_flags & KEXEC_ON_CRASH) { if (parse_iomem_single("Crash kernel\n", &crash_base, &crash_end)) @@ -165,6 +175,9 @@ image_s390_load(int argc, char **argv, const char *kernel_buf, ramdisk_origin = _ALIGN_UP(ramdisk_origin, 0x100000); add_segment_check(info, rd_buffer, ramdisk_len, ramdisk_origin, ramdisk_len); + } else if (reuse_initrd) { + ramdisk_origin = retained_initrd_base; + ramdisk_len = (off_t)retained_initrd_size; } if (info->kexec_flags & KEXEC_ON_CRASH) { if (load_crashdump_segments(info, crash_base, crash_end)) diff --git a/kexec/arch/s390/kexec-s390.c b/kexec/arch/s390/kexec-s390.c index 86c9fb8..fd0d87e 100644 --- a/kexec/arch/s390/kexec-s390.c +++ b/kexec/arch/s390/kexec-s390.c @@ -25,6 +25,20 @@ #include static struct memory_range memory_range[MAX_MEMORY_RANGES]; +unsigned long long retained_initrd_base, retained_initrd_size; +unsigned char reuse_initrd; + +void arch_reuse_initrd(void) +{ + uint64_t start, end; + + if (parse_iomem_single("initrd\n", &start, &end)) + die("Couldn't find initrd entry in /proc/iomem\n"); + + retained_initrd_base = (unsigned long long)start; + retained_initrd_size = (unsigned long long)end - retained_initrd_base + 1; + reuse_initrd = 1; +} /* * Read string from file diff --git a/kexec/arch/s390/kexec-s390.h b/kexec/arch/s390/kexec-s390.h index 6a99518..7e85976 100644 --- a/kexec/arch/s390/kexec-s390.h +++ b/kexec/arch/s390/kexec-s390.h @@ -34,5 +34,7 @@ extern int load_crashdump_segments(struct kexec_info *info, extern int get_memory_ranges_s390(struct memory_range range[], int *ranges, int with_crashk); extern int command_line_add(struct kexec_info *info, const char *str); +extern unsigned long long retained_initrd_base, retained_initrd_size; +extern unsigned char reuse_initrd; #endif /* KEXEC_S390_H */ -- 2.55.0 base commit: 29898e149feb5c615b3ab6313260d58315bf1d8d