On Thu, Apr 28, 2016 at 2:58 PM, Russell King <rmk+kernel at arm.linux.org.uk> wrote: > kexec physical addresses are the boot-time view of the system. For > certain ARM systems (such as Keystone 2), the boot view of the system > does not match the kernel's view of the system: the boot view uses a > special alias in the lower 4GB of the physical address space. > > To cater for these kinds of setups, we need to translate between the > boot view physical addresses and the normal kernel view physical > addresses. This patch extracts the current transation points into > linux/kexec.h, and allows an architecture to override the functions. > > Due to the translations required, we unfortunately end up with six > translation functions, which are reduced down to four that the > architecture can override. > > Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk> I must be missing something when I am thinking that, had we passed arch_phys_to_idmap_offset to user space, this patch would not have been needed, and things would have been more simpler. Please help me to understand why passing arch_phys_to_idmap_offset to user space would not be a good idea. ~Pratyush
