[POWERPC] Fix large hash table allocation on Cell blades

My recent hack to allocate the hash table under 1GB on cell was poorly
tested, *cough*. It turns out on blades with large amounts of memory we
fail to allocate the hash table at all. This is because RTAS has been
instantiated just below 768MB, and 0-x MB are used by the kernel,
leaving no areas that are both large enough and also naturally-aligned.

For the cell IOMMU hack the page tables must be under 2GB, so use that
as the limit instead. This has been tested on real hardware and boots
happily.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 32f416175db1..590f1f67c874 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -506,10 +506,10 @@ void __init htab_initialize(void)
         } else {
                 /* Find storage for the HPT.  Must be contiguous in
                  * the absolute address space. On cell we want it to be
-                 * in the first 1 Gig.
+                 * in the first 2 Gig so we can use it for IOMMU hacks.
                  */
                 if (machine_is(cell))
-                        limit = 0x40000000;
+                        limit = 0x80000000;
                 else
                         limit = 0;