[PATCH 0/3] kexec: refactor CONFIG_KEXEC/CONFIG_KEXEC_FILE Kconfig

[dyoung@redhat.com]

Previously Theodore Ts'o brought up an issue about kexec_load syscall bypassing
signature verification:
https://lkml.org/lkml/2015/6/14/280

Because we have two kexec load syscall, one kexec_load, another kexec_file_load,
the latter one was introduced by Vivek Goyal, it is mainly for supporting UEFI
secure boot. kexec_file_load verifies kernel signature, but even if with
CONFIG_KEXEC_VERIFY_SIG=y and CONFIG_KEXEC_FILE=y, kexec-tools still can use
old syscall and bypass signature verification.

KEXEC_FILE can also be used without UEFI, so kexec can always verify kernel
signature for security purpose. 

The suggestion in above thread is add a new Kconfig option for kexec common
code, here I use KEXEC_CORE, KEXEC and KEXEC_FILE select KEXEC_CORE so one can
compile only KEXEC_FILE without old kexec_load syscall.

There's checkpatch warnings and errors, I would like to send furthuer cleanup
patches after this series. Please let me know if you have other suggestions.
checkpatch errors are for cases such as assign a value to static variables.

PATCH 3/3 can be sort out from the series if people do not like. It is a
cleanup for a macro.

Below is the diffstat of the patches:
---
 arch/arm/Kconfig              |    4 
 arch/ia64/Kconfig             |    4 
 arch/m68k/Kconfig             |    4 
 arch/mips/Kconfig             |    4 
 arch/powerpc/Kconfig          |    4 
 arch/sh/Kconfig               |    4 
 arch/tile/Kconfig             |    4 
 arch/x86/Kconfig              |    6 
 arch/x86/boot/header.S        |    2 
 arch/x86/include/asm/kdebug.h |    5 
 arch/x86/kernel/Makefile      |    4 
 arch/x86/kernel/kvmclock.c    |    4 
 arch/x86/kernel/reboot.c      |    4 
 arch/x86/kernel/setup.c       |    2 
 arch/x86/kernel/vmlinux.lds.S |    2 
 arch/x86/kvm/vmx.c            |    8 
 arch/x86/platform/efi/efi.c   |    4 
 arch/x86/platform/uv/uv_nmi.c |    6 
 drivers/firmware/efi/Kconfig  |    2 
 drivers/pci/pci-driver.c      |    2 
 include/linux/kexec.h         |   12 
 init/initramfs.c              |    4 
 kernel/Makefile               |    2 
 kernel/events/core.c          |    2 
 kernel/kexec.c                | 2633 ------------------------------------------
 kernel/kexec_core.c           | 1594 +++++++++++++++++++++++++
 kernel/kexec_file.c           | 1044 ++++++++++++++++
 kernel/kexec_internal.h       |   22 
 kernel/ksysfs.c               |    6 
 kernel/printk/printk.c        |    2 
 kernel/reboot.c               |    2 
 kernel/sysctl.c               |    2 
 32 files changed, 2745 insertions(+), 2659 deletions(-)

Thanks
Dave