powerpc: Hugetlb for BookE

Enable hugepages on Freescale BookE processors.  This allows the kernel to
use huge TLB entries to map pages, which can greatly reduce the number of
TLB misses and the amount of TLB thrashing experienced by applications with
large memory footprints.  Care should be taken when using this on FSL
processors, as the number of large TLB entries supported by the core is low
(16-64) on current processors.

The supported set of hugepage sizes include 4m, 16m, 64m, 256m, and 1g.
Page sizes larger than the max zone size are called "gigantic" pages and
must be allocated on the command line (and cannot be deallocated).

This is currently only fully implemented for Freescale 32-bit BookE
processors, but there is some infrastructure in the code for
64-bit BooKE.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/mmu-book3e.h b/arch/powerpc/include/asm/mmu-book3e.h
index 3ea0f9a259d8..0260ea5ec3c2 100644
--- a/arch/powerpc/include/asm/mmu-book3e.h
+++ b/arch/powerpc/include/asm/mmu-book3e.h
@@ -66,6 +66,7 @@
 #define MAS2_M                  0x00000004
 #define MAS2_G                  0x00000002
 #define MAS2_E                  0x00000001
+#define MAS2_WIMGE_MASK         0x0000001f
 #define MAS2_EPN_MASK(size)             (~0 << (size + 10))
 #define MAS2_VAL(addr, size, flags)     ((addr) & MAS2_EPN_MASK(size) | (flags))
 
@@ -80,6 +81,7 @@
 #define MAS3_SW                 0x00000004
 #define MAS3_UR                 0x00000002
 #define MAS3_SR                 0x00000001
+#define MAS3_BAP_MASK           0x0000003f
 #define MAS3_SPSIZE             0x0000003e
 #define MAS3_SPSIZE_SHIFT       1
 
@@ -212,6 +214,11 @@ typedef struct {
         unsigned int    id;
         unsigned int    active;
         unsigned long   vdso_base;
+#ifdef CONFIG_PPC_MM_SLICES
+        u64 low_slices_psize;   /* SLB page size encodings */
+        u64 high_slices_psize;  /* 4 bits per slice for now */
+        u16 user_psize;         /* page size index */
+#endif
 } mm_context_t;
 
 /* Page size definitions, common between 32 and 64-bit