[PATCH v1 01/21] kexec: consolidate kexec and crash options into kernel/Kconfig.kexec

Eric DeVolder eric.devolder at oracle.com
Tue Jun 13 03:27:53 AEST 2023

The config options for kexec and crash features are consolidated
into new file kernel/Kconfig.kexec. Under the "General Setup" submenu
is a new submenu "Kexec and crash handling" where all the kexec and
crash options that were once in the arch-dependent submenu "Processor
type and features" are now consolidated.

The following options are impacted:


The three main options are KEXEC, KEXEC_FILE and CRASH_DUMP.

Architectures specify support of certain KEXEC and CRASH features with
similarly named new ARCH_HAS_<option> config options.

Architectures can utilize the new ARCH_SUPPORTS_<option> config
options to specify additional components when <option> is enabled.

To summarize, the ARCH_HAS_<option> permits the <option> to be
enabled, and the ARCH_SUPPORTS_<option> handles side effects (ie.
select statements).

Signed-off-by: Eric DeVolder <eric.devolder at oracle.com>
 arch/Kconfig         |  13 ------
 init/Kconfig         |   2 +
 kernel/Kconfig.kexec | 103 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 13 deletions(-)
 create mode 100644 kernel/Kconfig.kexec

diff --git a/arch/Kconfig b/arch/Kconfig
index 205fd23e0cad..a37730679730 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -11,19 +11,6 @@ source "arch/$(SRCARCH)/Kconfig"
 menu "General architecture-dependent options"
-config CRASH_CORE
-	bool
-config KEXEC_CORE
-	select CRASH_CORE
-	bool
-config KEXEC_ELF
-	bool
-	bool
diff --git a/init/Kconfig b/init/Kconfig
index 32c24950c4ce..4424447e23a5 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1917,6 +1917,8 @@ config BINDGEN_VERSION_TEXT
+source "kernel/Kconfig.kexec"
 endmenu		# General setup
 source "arch/Kconfig"
diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
new file mode 100644
index 000000000000..660048099865
--- /dev/null
+++ b/kernel/Kconfig.kexec
@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Kexec and crash features"
+config CRASH_CORE
+	bool
+config KEXEC_CORE
+	select CRASH_CORE
+	bool
+config KEXEC_ELF
+	bool
+	bool
+config KEXEC
+	bool "Enable kexec system call"
+	depends on ARCH_HAS_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_HAS_KEXEC_FILE
+	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 previous system call.
+config KEXEC_SIG
+	bool "Verify kernel signature during kexec_file_load() syscall"
+	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.
+	bool "Require a valid signature in kexec_file_load() syscall"
+	depends on KEXEC_SIG
+	help
+	  This option makes kernel signature verification mandatory for
+	  the kexec_file_load() syscall.
+	bool "Enable bzImage signature verification support"
+	depends on KEXEC_SIG
+	help
+	  Enable bzImage signature verification support.
+config KEXEC_JUMP
+	bool "kexec jump"
+	depends on KEXEC && HIBERNATION
+	depends on ARCH_HAS_KEXEC_JUMP
+	help
+	  Jump between original kernel and kexeced kernel and invoke
+	  code in physical address mode via KEXEC
+config CRASH_DUMP
+	bool "kernel crash dumps"
+	depends on ARCH_HAS_CRASH_DUMP
+	select KEXEC_CORE
+	select CRASH_CORE
+	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
+	  For more details see Documentation/admin-guide/kdump/kdump.rst
+	  For s390, this option also enables zfcpdump.
+	  See also <file:Documentation/s390/zfcpdump.rst>

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