[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>

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 32f416175db10f9c6266ea48c56bf5b69becb952..590f1f67c87403df6db3f878c800a7c37bf992b4 100644 (file)
--- 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;