x86: fix init_memory_mapping() to handle small ranges
x86: fix init_memory_mapping() to handle small ranges

Impact: fix failed EFI bootup in certain circumstances

Ying Huang found init_memory_mapping() has problem with small ranges
less than 2M when he tried to direct map the EFI runtime code out of
max_low_pfn_mapped.

It turns out we never considered that case and didn't check the range...

Reported-by: Ying Huang <b1ed892af366400004b51f70e40351e33707b6c4@intel.com>
Signed-off-by: Yinghai Lu <0674548f4d596393408a51d6287a76ebba2f42aa@kernel.org>
Cc: Brian Maly <bd72fa1ccf04c98ece22557a381bb8516812ab4e@redhat.com>
LKML-Reference: <b8789af904b2f88a40f3978d66ed70343c97e990@kernel.org>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs