On 2023/6/13 1:27, Eric DeVolder wrote:
> 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:
>
> - KEXEC
> - KEXEC_FILE
> - KEXEC_SIG
> - KEXEC_SIG_FORCE
> - KEXEC_BZIMAGE_VERIFY_SIG
> - KEXEC_JUMP
> - CRASH_DUMP
>
> 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.devol...@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
> -
> -config HAVE_IMA_KEXEC
> - bool
> -
> config ARCH_HAS_SUBPAGE_FAULTS
> bool
> help
> 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
> config TRACEPOINTS
> bool
>
> +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
> +
> +config HAVE_IMA_KEXEC
> + bool
> +
> +config KEXEC
> + bool "Enable kexec system call"
> + default ARCH_DEFAULT_KEXEC
> + 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.
"kernel. It is like", "firmware. And like"
A few more spaces, I don't know the original author's intention, perhaps can be
removed.
> +
> + 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"
> + depends on KEXEC_FILE && MODULE_SIG_FORMAT
I see that there is no "depends on MODULE_SIG_FORMAT" on x86 and arm64.
> + help
> +
This blank line can be deleted.
> + 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.
> +
> +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 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
> + (CONFIG_RELOCATABLE=y).
> + For more details see Documentation/admin-guide/kdump/kdump.rst
> +
> + For s390, this option also enables zfcpdump.
> + See also <file:Documentation/s390/zfcpdump.rst>
> +
> +endmenu
>
--
Regards,
Zhen Lei
