# SPDX-License-Identifier: GPL-2.0-only menu "Kexec and crash features" config CRASH_RESERVE	bool config VMCORE_INFO	bool config KEXEC_CORE	bool config KEXEC_ELF	bool config HAVE_IMA_KEXEC	bool config KEXEC	bool "Enable kexec system call"	depends on ARCH_SUPPORTS_KEXEC	select KEXEC_CORE	help	  kexec is a system call that implements the ability to shutdown your	  current kernel, and to start another kernel. It is like a reboot	  but it is independent of the system firmware. And like a reboot	  you can start any kernel with it, not just Linux. 	  The name comes from the similarity to the exec system call. 	  It is an ongoing process to be certain the hardware in a machine	  is properly shutdown, so do not be surprised if this code does not	  initially work for you. As of this writing the exact hardware	  interface is strongly in flux, so no good recommendation can be	  made. config KEXEC_FILE	bool "Enable kexec file based system call"	depends on ARCH_SUPPORTS_KEXEC_FILE	select CRYPTO_LIB_SHA256	select KEXEC_CORE	help	  This is new version of kexec system call. This system call is	  file based and takes file descriptors as system call argument	  for kernel and initramfs as opposed to list of segments as	  accepted by kexec system call. config KEXEC_SIG	bool "Verify kernel signature during kexec_file_load() syscall"	depends on ARCH_SUPPORTS_KEXEC_SIG	depends on KEXEC_FILE	help	  This option makes the kexec_file_load() syscall check for a valid	  signature of the kernel image. The image can still be loaded without	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if	  there's a signature that we can check, then it must be valid. 	  In addition to this option, you need to enable signature	  verification for the corresponding kernel image type being	  loaded in order for this to work. config KEXEC_SIG_FORCE	bool "Require a valid signature in kexec_file_load() syscall"	depends on ARCH_SUPPORTS_KEXEC_SIG_FORCE	depends on KEXEC_SIG	help	  This option makes kernel signature verification mandatory for	  the kexec_file_load() syscall. config KEXEC_IMAGE_VERIFY_SIG	bool "Enable Image signature verification support (ARM)"	default ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG	depends on ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG	depends on KEXEC_SIG	depends on EFI && SIGNED_PE_FILE_VERIFICATION	help	  Enable Image signature verification support. config KEXEC_BZIMAGE_VERIFY_SIG	bool "Enable bzImage signature verification support"	depends on ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG	depends on KEXEC_SIG	depends on SIGNED_PE_FILE_VERIFICATION	select SYSTEM_TRUSTED_KEYRING	help	  Enable bzImage signature verification support. config KEXEC_JUMP	bool "kexec jump"	depends on ARCH_SUPPORTS_KEXEC_JUMP	depends on KEXEC && HIBERNATION	help	  Jump between original kernel and kexeced kernel and invoke	  code in physical address mode via KEXEC config CRASH_DUMP	bool "kernel crash dumps"	default ARCH_DEFAULT_CRASH_DUMP	depends on ARCH_SUPPORTS_CRASH_DUMP	depends on KEXEC_CORE	select VMCORE_INFO	select CRASH_RESERVE	help	  Generate crash dump after being started by kexec.	  This should be normally only set in special crash dump kernels	  which are loaded in the main kernel with kexec-tools into	  a specially reserved region and then later executed after	  a crash by kdump/kexec. The crash dump kernel must be compiled	  to a memory address not used by the main kernel or BIOS using	  PHYSICAL_START, or it must be built as a relocatable image	  (CONFIG_RELOCATABLE=y).	  For more details see Documentation/admin-guide/kdump/kdump.rst 	  For s390, this option also enables zfcpdump.	  See also <file:Documentation/arch/s390/zfcpdump.rst> config CRASH_DM_CRYPT	bool "Support saving crash dump to dm-crypt encrypted volume"	depends on KEXEC_FILE	depends on CRASH_DUMP	depends on DM_CRYPT	depends on KEYS	help	  With this option enabled, user space can intereact with	  /sys/kernel/config/crash_dm_crypt_keys to make the dm crypt keys	  persistent for the dump-capture kernel. config CRASH_DM_CRYPT_CONFIGS	def_tristate CRASH_DM_CRYPT	select CONFIGFS_FS	help	  CRASH_DM_CRYPT cannot directly select CONFIGFS_FS, because that	  is required to be built-in. config CRASH_DUMP_KUNIT_TEST	tristate "Unit Tests for kernel crash dumps" if !KUNIT_ALL_TESTS	depends on CRASH_DUMP && KUNIT	default KUNIT_ALL_TESTS	help	  This option builds KUnit unit tests for kernel crash dumps. The unit	  tests will be used to verify the correctness of covered functions and	  also prevent any regression. 	  If unsure, say N. config CRASH_HOTPLUG	bool "Update the crash elfcorehdr on system configuration changes"	default y	depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG)	depends on ARCH_SUPPORTS_CRASH_HOTPLUG	help	  Enable direct update to the crash elfcorehdr (which contains	  the list of CPUs and memory regions to be dumped upon a crash)	  in response to hot plug/unplug or online/offline of CPUs or	  memory. This is a much more advanced approach than userspace	  attempting that. 	  If unsure, say Y. config CRASH_MAX_MEMORY_RANGES	int "Specify the maximum number of memory regions for the elfcorehdr"	default 8192	depends on CRASH_HOTPLUG	help	  For the kexec_file_load() syscall path, specify the maximum number of	  memory regions that the elfcorehdr buffer/segment can accommodate.	  These regions are obtained via walk_system_ram_res(); eg. the	  'System RAM' entries in /proc/iomem.	  This value is combined with NR_CPUS_DEFAULT and multiplied by	  sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/	  segment size.	  The value 8192, for example, covers a (sparsely populated) 1TiB system	  consisting of 128MiB memblocks, while resulting in an elfcorehdr	  memory buffer/segment size under 1MiB. This represents a sane choice	  to accommodate both baremetal and virtual machine configurations. 	  For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of	  the computation behind the value provided through the	  /sys/kernel/crash_elfcorehdr_size attribute. endmenu