Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
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