--- arch/arm/Kconfig

+++ arch/arm/Kconfig

@@ -20,6 +20,7 @@ config ARM

select HAVE_KERNEL_GZIP

select HAVE_KERNEL_LZO

select HAVE_KERNEL_LZMA

+ select HAVE_KERNEL_XZ

select HAVE_IRQ_WORK

select HAVE_PERF_EVENTS

select PERF_USE_VMALLOC

@@ -2025,6 +2026,36 @@ config ATAGS_PROC

Should the atags used to boot the kernel be exported in an "atags"

file in procfs. Useful with kexec.

+config KEXEC_HARDBOOT

+ bool "Support hard booting to a kexec kernel"

+ depends on KEXEC

+ help

+ Allows hard booting (i.e., with a full hardware reboot) to a kernel

+ previously loaded in memory by kexec. This works around the problem of

+ soft-booted kernel hangs due to improper device shutdown and/or

+ reinitialization. Support is comprised of two components:

+

+ First, a "hardboot" flag is added to the kexec syscall to force a hard

+ reboot in relocate_new_kernel() (which requires machine-specific assembly

+ code). This also requires the kexec userspace tool to load the kexec'd

+ kernel in memory region left untouched by the bootloader (i.e., not

+ explicitly cleared and not overwritten by the boot kernel). Just prior

+ to reboot, the kexec kernel arguments are stashed in a machine-specific

+ memory page that must also be preserved. Note that this hardboot page

+ need not be reserved during regular kernel execution.

+

+ Second, the zImage decompresor of the boot (bootloader-loaded) kernel is

+ modified to check the hardboot page for fresh kexec arguments, and if

+ present, attempts to jump to the kexec'd kernel preserved in memory.

+

+ Note that hardboot support is only required in the boot kernel and any

+ kernel capable of performing a hardboot kexec. It is _not_ required by a

+ kexec'd kernel.

+

+config KEXEC_HB_PAGE_ADDR

+ hex "Kexec hardboot page address"

+ depends on KEXEC_HARDBOOT

+

config CRASH_DUMP

bool "Build kdump crash kernel (EXPERIMENTAL)"

depends on EXPERIMENTAL