1# SPDX-License-Identifier: GPL-2.0-only 2 3menu "Kexec and crash features" 4 5config CRASH_RESERVE 6 bool 7 8config VMCORE_INFO 9 bool 10 11config KEXEC_CORE 12 bool 13 14config KEXEC_ELF 15 bool 16 17config HAVE_IMA_KEXEC 18 bool 19 20config KEXEC 21 bool "Enable kexec system call" 22 depends on ARCH_SUPPORTS_KEXEC 23 select KEXEC_CORE 24 help 25 kexec is a system call that implements the ability to shutdown your 26 current kernel, and to start another kernel. It is like a reboot 27 but it is independent of the system firmware. And like a reboot 28 you can start any kernel with it, not just Linux. 29 30 The name comes from the similarity to the exec system call. 31 32 It is an ongoing process to be certain the hardware in a machine 33 is properly shutdown, so do not be surprised if this code does not 34 initially work for you. As of this writing the exact hardware 35 interface is strongly in flux, so no good recommendation can be 36 made. 37 38config KEXEC_FILE 39 bool "Enable kexec file based system call" 40 depends on ARCH_SUPPORTS_KEXEC_FILE 41 select CRYPTO_LIB_SHA256 42 select KEXEC_CORE 43 help 44 This is new version of kexec system call. This system call is 45 file based and takes file descriptors as system call argument 46 for kernel and initramfs as opposed to list of segments as 47 accepted by kexec system call. 48 49config KEXEC_SIG 50 bool "Verify kernel signature during kexec_file_load() syscall" 51 depends on ARCH_SUPPORTS_KEXEC_SIG 52 depends on KEXEC_FILE 53 help 54 This option makes the kexec_file_load() syscall check for a valid 55 signature of the kernel image. The image can still be loaded without 56 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 57 there's a signature that we can check, then it must be valid. 58 59 In addition to this option, you need to enable signature 60 verification for the corresponding kernel image type being 61 loaded in order for this to work. 62 63config KEXEC_SIG_FORCE 64 bool "Require a valid signature in kexec_file_load() syscall" 65 depends on ARCH_SUPPORTS_KEXEC_SIG_FORCE 66 depends on KEXEC_SIG 67 help 68 This option makes kernel signature verification mandatory for 69 the kexec_file_load() syscall. 70 71config KEXEC_IMAGE_VERIFY_SIG 72 bool "Enable Image signature verification support (ARM)" 73 default ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG 74 depends on ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG 75 depends on KEXEC_SIG 76 depends on EFI && SIGNED_PE_FILE_VERIFICATION 77 help 78 Enable Image signature verification support. 79 80config KEXEC_BZIMAGE_VERIFY_SIG 81 bool "Enable bzImage signature verification support" 82 depends on ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 83 depends on KEXEC_SIG 84 depends on SIGNED_PE_FILE_VERIFICATION 85 select SYSTEM_TRUSTED_KEYRING 86 help 87 Enable bzImage signature verification support. 88 89config KEXEC_JUMP 90 bool "kexec jump" 91 depends on ARCH_SUPPORTS_KEXEC_JUMP 92 depends on KEXEC && HIBERNATION 93 help 94 Jump between original kernel and kexeced kernel and invoke 95 code in physical address mode via KEXEC 96 97config KEXEC_HANDOVER 98 bool "kexec handover" 99 depends on ARCH_SUPPORTS_KEXEC_HANDOVER && ARCH_SUPPORTS_KEXEC_FILE 100 select MEMBLOCK_KHO_SCRATCH 101 select KEXEC_FILE 102 select DEBUG_FS 103 select LIBFDT 104 select CMA 105 help 106 Allow kexec to hand over state across kernels by generating and 107 passing additional metadata to the target kernel. This is useful 108 to keep data or state alive across the kexec. For this to work, 109 both source and target kernels need to have this option enabled. 110 111config CRASH_DUMP 112 bool "kernel crash dumps" 113 default ARCH_DEFAULT_CRASH_DUMP 114 depends on ARCH_SUPPORTS_CRASH_DUMP 115 depends on KEXEC_CORE 116 select VMCORE_INFO 117 select CRASH_RESERVE 118 help 119 Generate crash dump after being started by kexec. 120 This should be normally only set in special crash dump kernels 121 which are loaded in the main kernel with kexec-tools into 122 a specially reserved region and then later executed after 123 a crash by kdump/kexec. The crash dump kernel must be compiled 124 to a memory address not used by the main kernel or BIOS using 125 PHYSICAL_START, or it must be built as a relocatable image 126 (CONFIG_RELOCATABLE=y). 127 For more details see Documentation/admin-guide/kdump/kdump.rst 128 129 For s390, this option also enables zfcpdump. 130 See also <file:Documentation/arch/s390/zfcpdump.rst> 131 132config CRASH_DM_CRYPT 133 bool "Support saving crash dump to dm-crypt encrypted volume" 134 depends on KEXEC_FILE 135 depends on CRASH_DUMP 136 depends on DM_CRYPT 137 depends on KEYS 138 help 139 With this option enabled, user space can intereact with 140 /sys/kernel/config/crash_dm_crypt_keys to make the dm crypt keys 141 persistent for the dump-capture kernel. 142 143config CRASH_DM_CRYPT_CONFIGS 144 def_tristate CRASH_DM_CRYPT 145 select CONFIGFS_FS 146 help 147 CRASH_DM_CRYPT cannot directly select CONFIGFS_FS, because that 148 is required to be built-in. 149 150config CRASH_HOTPLUG 151 bool "Update the crash elfcorehdr on system configuration changes" 152 default y 153 depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG) 154 depends on ARCH_SUPPORTS_CRASH_HOTPLUG 155 help 156 Enable direct update to the crash elfcorehdr (which contains 157 the list of CPUs and memory regions to be dumped upon a crash) 158 in response to hot plug/unplug or online/offline of CPUs or 159 memory. This is a much more advanced approach than userspace 160 attempting that. 161 162 If unsure, say Y. 163 164config CRASH_MAX_MEMORY_RANGES 165 int "Specify the maximum number of memory regions for the elfcorehdr" 166 default 8192 167 depends on CRASH_HOTPLUG 168 help 169 For the kexec_file_load() syscall path, specify the maximum number of 170 memory regions that the elfcorehdr buffer/segment can accommodate. 171 These regions are obtained via walk_system_ram_res(); eg. the 172 'System RAM' entries in /proc/iomem. 173 This value is combined with NR_CPUS_DEFAULT and multiplied by 174 sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/ 175 segment size. 176 The value 8192, for example, covers a (sparsely populated) 1TiB system 177 consisting of 128MiB memblocks, while resulting in an elfcorehdr 178 memory buffer/segment size under 1MiB. This represents a sane choice 179 to accommodate both baremetal and virtual machine configurations. 180 181 For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of 182 the computation behind the value provided through the 183 /sys/kernel/crash_elfcorehdr_size attribute. 184 185endmenu 186