On Fri, Apr 29, 2016 at 08:44:29PM +0530, Pratyush Anand wrote: > 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. Sorry, I disagree. Even if we thought that passing the offset to userspace would be a good idea, it does nothing to solve each site in this patch. This patch would still be necessary. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
