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