Subject: [PATCH v6 02/14] x86/kexec: refactor for kernel/Kconfig.kexec

From: Eric DeVolder <[email-masked]>
Date: Wed, 12 Jul 2023 12:15:33 -0400

The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.

Signed-off-by: Eric DeVolder <[email-masked]>
---
 arch/x86/Kconfig | 92 ++++++++++--------------------------------------
 1 file changed, 19 insertions(+), 73 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7422db409770..9767a343f7c2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2040,88 +2040,34 @@ config EFI_RUNTIME_MAP
 
 source "kernel/Kconfig.hz"
 
-config KEXEC
-	bool "kexec system call"
-	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 "kexec file based system call"
-	select KEXEC_CORE
-	select HAVE_IMA_KEXEC if IMA
-	depends on X86_64
-	depends on CRYPTO=y
-	depends on CRYPTO_SHA256=y
-	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 ARCH_SUPPORTS_KEXEC
+	def_bool y
 
-config ARCH_HAS_KEXEC_PURGATORY
-	def_bool KEXEC_FILE
+config ARCH_SUPPORTS_KEXEC_FILE
+	def_bool X86_64 && CRYPTO && CRYPTO_SHA256
 
-config KEXEC_SIG
-	bool "Verify kernel signature during kexec_file_load() syscall"
+config ARCH_SELECTS_KEXEC_FILE
+	def_bool y
 	depends on KEXEC_FILE
-	help
+	select HAVE_IMA_KEXEC if IMA
 
-	  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.
+config ARCH_HAS_KEXEC_PURGATORY
+	def_bool KEXEC_FILE
 
-	  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 ARCH_SUPPORTS_KEXEC_SIG
+	def_bool y
 
-config KEXEC_SIG_FORCE
-	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.
+config ARCH_SUPPORTS_KEXEC_SIG_FORCE
+	def_bool y
 
-config KEXEC_BZIMAGE_VERIFY_SIG
-	bool "Enable bzImage signature verification support"
-	depends on KEXEC_SIG
-	depends on SIGNED_PE_FILE_VERIFICATION
-	select SYSTEM_TRUSTED_KEYRING
-	help
-	  Enable bzImage signature verification support.
+config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
+	def_bool y
 
-config CRASH_DUMP
-	bool "kernel crash dumps"
-	depends on X86_64 || (X86_32 && HIGHMEM)
-	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
+config ARCH_SUPPORTS_KEXEC_JUMP
+	def_bool y
 
-config KEXEC_JUMP
-	bool "kexec jump"
-	depends on KEXEC && HIBERNATION
-	help
-	  Jump between original kernel and kexeced kernel and invoke
-	  code in physical address mode via KEXEC
+config ARCH_SUPPORTS_CRASH_DUMP
+	def_bool X86_64 || (X86_32 && HIGHMEM)
 
 config PHYSICAL_START
 	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
-- 
2.31.1