[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 96843211cc5c..7f64f0464d44 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -554,12 +554,10 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 #ifdef CONFIG_PPC64
         if (cpu_has_feature(CPU_FTR_SLB)) {
                 unsigned long sp_vsid = get_kernel_vsid(sp);
+                unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 
                 sp_vsid <<= SLB_VSID_SHIFT;
-                sp_vsid |= SLB_VSID_KERNEL;
-                if (cpu_has_feature(CPU_FTR_16M_PAGE))
-                        sp_vsid |= SLB_VSID_L;
-
+                sp_vsid |= SLB_VSID_KERNEL | llp;
                 p->thread.ksp_vsid = sp_vsid;
         }