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 CRASH_DUMP 98 bool "kernel crash dumps" 99 default ARCH_DEFAULT_CRASH_DUMP 100 depends on ARCH_SUPPORTS_CRASH_DUMP 101 depends on KEXEC_CORE 102 select VMCORE_INFO 103 select CRASH_RESERVE 104 help 105 Generate crash dump after being started by kexec. 106 This should be normally only set in special crash dump kernels 107 which are loaded in the main kernel with kexec-tools into 108 a specially reserved region and then later executed after 109 a crash by kdump/kexec. The crash dump kernel must be compiled 110 to a memory address not used by the main kernel or BIOS using 111 PHYSICAL_START, or it must be built as a relocatable image 112 (CONFIG_RELOCATABLE=y). 113 For more details see Documentation/admin-guide/kdump/kdump.rst 114 115 For s390, this option also enables zfcpdump. 116 See also <file:Documentation/arch/s390/zfcpdump.rst> 117 118config CRASH_DM_CRYPT 119 bool "Support saving crash dump to dm-crypt encrypted volume" 120 depends on KEXEC_FILE 121 depends on CRASH_DUMP 122 depends on DM_CRYPT 123 depends on CONFIGFS_FS 124 help 125 With this option enabled, user space can intereact with 126 /sys/kernel/config/crash_dm_crypt_keys to make the dm crypt keys 127 persistent for the dump-capture kernel. 128 129config CRASH_HOTPLUG 130 bool "Update the crash elfcorehdr on system configuration changes" 131 default y 132 depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG) 133 depends on ARCH_SUPPORTS_CRASH_HOTPLUG 134 help 135 Enable direct update to the crash elfcorehdr (which contains 136 the list of CPUs and memory regions to be dumped upon a crash) 137 in response to hot plug/unplug or online/offline of CPUs or 138 memory. This is a much more advanced approach than userspace 139 attempting that. 140 141 If unsure, say Y. 142 143config CRASH_MAX_MEMORY_RANGES 144 int "Specify the maximum number of memory regions for the elfcorehdr" 145 default 8192 146 depends on CRASH_HOTPLUG 147 help 148 For the kexec_file_load() syscall path, specify the maximum number of 149 memory regions that the elfcorehdr buffer/segment can accommodate. 150 These regions are obtained via walk_system_ram_res(); eg. the 151 'System RAM' entries in /proc/iomem. 152 This value is combined with NR_CPUS_DEFAULT and multiplied by 153 sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/ 154 segment size. 155 The value 8192, for example, covers a (sparsely populated) 1TiB system 156 consisting of 128MiB memblocks, while resulting in an elfcorehdr 157 memory buffer/segment size under 1MiB. This represents a sane choice 158 to accommodate both baremetal and virtual machine configurations. 159 160 For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of 161 the computation behind the value provided through the 162 /sys/kernel/crash_elfcorehdr_size attribute. 163 164endmenu 165