tree ff80abf80bdbae23fe8bd6e51967f11af3723b65
parent 00d1c5e05736f947687be27706bda01cec104e57
author Andi Kleen <ak@suse.de> 1208446845 +0200
committer Ingo Molnar <mingo@elte.hu> 1208446845 +0200

x86: do kernel direct mapping at boot using GB pages

The AMD Fam10h CPUs support new Gigabyte page table entry for
mapping 1GB at a time. Use this for the kernel direct mapping.

Only done for 64bit because i386 does not support GB page tables.

This only applies to the data portion of the direct mapping; the
kernel text mapping stays with 2MB pages because the AMD Fam10h
microarchitecture does not support GB ITLBs and AMD recommends
against using GB mappings for code.

Can be disabled with disable_gbpages on the kernel command line

[ tglx@linutronix.de: simplify enable code ]
[ Yinghai Lu <yinghai.lu@sun.com>: boot fix on 256 GB RAM ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>