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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 KEYS
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_DM_CRYPT_CONFIGS
130 def_tristate CRASH_DM_CRYPT
131 select CONFIGFS_FS
132 help
133 CRASH_DM_CRYPT cannot directly select CONFIGFS_FS, because that
134 is required to be built-in.
135
136config CRASH_DUMP_KUNIT_TEST
137 tristate "Unit Tests for kernel crash dumps" if !KUNIT_ALL_TESTS
138 depends on CRASH_DUMP && KUNIT
139 default KUNIT_ALL_TESTS
140 help
141 This option builds KUnit unit tests for kernel crash dumps. The unit
142 tests will be used to verify the correctness of covered functions and
143 also prevent any regression.
144
145 If unsure, say N.
146
147config CRASH_HOTPLUG
148 bool "Update the crash elfcorehdr on system configuration changes"
149 default y
150 depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG)
151 depends on ARCH_SUPPORTS_CRASH_HOTPLUG
152 help
153 Enable direct update to the crash elfcorehdr (which contains
154 the list of CPUs and memory regions to be dumped upon a crash)
155 in response to hot plug/unplug or online/offline of CPUs or
156 memory. This is a much more advanced approach than userspace
157 attempting that.
158
159 If unsure, say Y.
160
161config CRASH_MAX_MEMORY_RANGES
162 int "Specify the maximum number of memory regions for the elfcorehdr"
163 default 8192
164 depends on CRASH_HOTPLUG
165 help
166 For the kexec_file_load() syscall path, specify the maximum number of
167 memory regions that the elfcorehdr buffer/segment can accommodate.
168 These regions are obtained via walk_system_ram_res(); eg. the
169 'System RAM' entries in /proc/iomem.
170 This value is combined with NR_CPUS and multiplied by
171 sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/
172 segment size.
173 The value 8192, for example, covers a (sparsely populated) 1TiB system
174 consisting of 128MiB memblocks, while resulting in an elfcorehdr
175 memory buffer/segment size under 1MiB. This represents a sane choice
176 to accommodate both baremetal and virtual machine configurations.
177
178 For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of
179 the computation behind the value provided through the
180 /sys/kernel/crash_elfcorehdr_size attribute.
181
182endmenu