1 # SPDX-License-Identifier: GPL-2.0-only 2 3 menu "Kexec and crash features" 4 5 config CRASH_RESERVE 6 bool 7 8 config VMCORE_INFO 9 bool 10 11 config KEXEC_CORE 12 bool 13 14 config KEXEC_ELF 15 bool 16 17 config HAVE_IMA_KEXEC 18 bool 19 20 config 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 38 config KEXEC_FILE 39 bool "Enable kexec file based system call" 40 depends on ARCH_SUPPORTS_KEXEC_FILE 41 select CRYPTO 42 select CRYPTO_SHA256 43 select KEXEC_CORE 44 help 45 This is new version of kexec system call. This system call is 46 file based and takes file descriptors as system call argument 47 for kernel and initramfs as opposed to list of segments as 48 accepted by kexec system call. 49 50 config KEXEC_SIG 51 bool "Verify kernel signature during kexec_file_load() syscall" 52 depends on ARCH_SUPPORTS_KEXEC_SIG 53 depends on KEXEC_FILE 54 help 55 This option makes the kexec_file_load() syscall check for a valid 56 signature of the kernel image. The image can still be loaded without 57 a valid signature unless you also enable KEXEC_SIG_FORCE, though if 58 there's a signature that we can check, then it must be valid. 59 60 In addition to this option, you need to enable signature 61 verification for the corresponding kernel image type being 62 loaded in order for this to work. 63 64 config KEXEC_SIG_FORCE 65 bool "Require a valid signature in kexec_file_load() syscall" 66 depends on ARCH_SUPPORTS_KEXEC_SIG_FORCE 67 depends on KEXEC_SIG 68 help 69 This option makes kernel signature verification mandatory for 70 the kexec_file_load() syscall. 71 72 config KEXEC_IMAGE_VERIFY_SIG 73 bool "Enable Image signature verification support (ARM)" 74 default ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG 75 depends on ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG 76 depends on KEXEC_SIG 77 depends on EFI && SIGNED_PE_FILE_VERIFICATION 78 help 79 Enable Image signature verification support. 80 81 config KEXEC_BZIMAGE_VERIFY_SIG 82 bool "Enable bzImage signature verification support" 83 depends on ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG 84 depends on KEXEC_SIG 85 depends on SIGNED_PE_FILE_VERIFICATION 86 select SYSTEM_TRUSTED_KEYRING 87 help 88 Enable bzImage signature verification support. 89 90 config KEXEC_JUMP 91 bool "kexec jump" 92 depends on ARCH_SUPPORTS_KEXEC_JUMP 93 depends on KEXEC && HIBERNATION 94 help 95 Jump between original kernel and kexeced kernel and invoke 96 code in physical address mode via KEXEC 97 98 config CRASH_DUMP 99 bool "kernel crash dumps" 100 default y 101 depends on ARCH_SUPPORTS_CRASH_DUMP 102 depends on KEXEC_CORE 103 select VMCORE_INFO 104 select CRASH_RESERVE 105 help 106 Generate crash dump after being started by kexec. 107 This should be normally only set in special crash dump kernels 108 which are loaded in the main kernel with kexec-tools into 109 a specially reserved region and then later executed after 110 a crash by kdump/kexec. The crash dump kernel must be compiled 111 to a memory address not used by the main kernel or BIOS using 112 PHYSICAL_START, or it must be built as a relocatable image 113 (CONFIG_RELOCATABLE=y). 114 For more details see Documentation/admin-guide/kdump/kdump.rst 115 116 For s390, this option also enables zfcpdump. 117 See also <file:Documentation/arch/s390/zfcpdump.rst> 118 119 config CRASH_HOTPLUG 120 bool "Update the crash elfcorehdr on system configuration changes" 121 default y 122 depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG) 123 depends on ARCH_SUPPORTS_CRASH_HOTPLUG 124 help 125 Enable direct update to the crash elfcorehdr (which contains 126 the list of CPUs and memory regions to be dumped upon a crash) 127 in response to hot plug/unplug or online/offline of CPUs or 128 memory. This is a much more advanced approach than userspace 129 attempting that. 130 131 If unsure, say Y. 132 133 config CRASH_MAX_MEMORY_RANGES 134 int "Specify the maximum number of memory regions for the elfcorehdr" 135 default 8192 136 depends on CRASH_HOTPLUG 137 help 138 For the kexec_file_load() syscall path, specify the maximum number of 139 memory regions that the elfcorehdr buffer/segment can accommodate. 140 These regions are obtained via walk_system_ram_res(); eg. the 141 'System RAM' entries in /proc/iomem. 142 This value is combined with NR_CPUS_DEFAULT and multiplied by 143 sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/ 144 segment size. 145 The value 8192, for example, covers a (sparsely populated) 1TiB system 146 consisting of 128MiB memblocks, while resulting in an elfcorehdr 147 memory buffer/segment size under 1MiB. This represents a sane choice 148 to accommodate both baremetal and virtual machine configurations. 149 150 For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of 151 the computation behind the value provided through the 152 /sys/kernel/crash_elfcorehdr_size attribute. 153 154 endmenu
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