[PATCH v3 02/13] x86/kexec: refactor for kernel/Kconfig.kexec

From: Eric DeVolder
Date: Mon Jun 26 2023 - 12:15:27 EST


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 <eric.devolder@xxxxxxxxxx>
---
arch/x86/Kconfig | 89 +++++++-----------------------------------------
1 file changed, 13 insertions(+), 76 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 53bab123a8ee..1afc6ca2986b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2043,88 +2043,25 @@ 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
-
- 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 KEXEC_SIG
- help
- This option makes kernel signature verification mandatory for
- the kexec_file_load() syscall.
+ select HAVE_IMA_KEXEC if IMA

-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_HAS_KEXEC_PURGATORY
+ def_bool KEXEC_FILE

-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