[Cbe-oss-dev] [PATCH] Fix large hash table allocation on Cell blades

[Michael Ellerman]

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 at ellerman.id.au>
---
 arch/powerpc/mm/hash_utils_64.c |    4 ++--
 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 32f4161..590f1f6 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;
 
-- 
1.5.2.rc1.1884.g59b20