[PATCH 2.0.2] use /proc/iomem for map with "add_efi_memmap" kernel option

[Simon Horman]

On Wed, Apr 27, 2011 at 08:56:09AM -0400, Ben Romer wrote:
> This patch changes the behavior of the kexec loader when the
> "add_efi_memmap" option is present on the currently running kernel's
> command line, to read the kernel memory map from /proc/iomem instead
> of /sys/firmware/memmap. 
> 
> On EFI systems, sometimes the e820 table is missing or incomplete.
> Systems like these use the "add_efi_memmap" option to add EFI's memory
> table entries to the kernel's memory table to build a complete picture
> of the system's memory; however, using the option does not add these
> entries to the table used to populate /sys/firmware/memmap, which is
> meant to be a pristine original copy. 
> 
> The kexec loader uses the pristine memory map by default, which causes
> problems when the loader doesn't have a complete picture of the system
> and incorrectly loads the kernel or ramdisk in places that aren't
> actually usable. This change makes the kexec loader check the running
> kernel's command line for the "add_efi_memmap" option and if it finds
> it, will use the modified map instead of the original map.
> 
> signed-off-by: Benjamin Romer <benjamin.romer at unisys.com>

Thanks, applied.