[POWERPC] Use 1TB segments

This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).

We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.

We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments.  That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.

Parts of this patch were originally written by Ben Herrenschmidt.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/asm-powerpc/tlbflush.h b/include/asm-powerpc/tlbflush.h
index 99a0439baa50..a022f806bb21 100644
--- a/include/asm-powerpc/tlbflush.h
+++ b/include/asm-powerpc/tlbflush.h
@@ -97,6 +97,7 @@ struct ppc64_tlb_batch {
 	real_pte_t		pte[PPC64_TLB_BATCH_NR];
 	unsigned long		vaddr[PPC64_TLB_BATCH_NR];
 	unsigned int		psize;
+	int			ssize;
 };
 DECLARE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
 
@@ -127,7 +128,7 @@ static inline void arch_leave_lazy_mmu_mode(void)
 
 
 extern void flush_hash_page(unsigned long va, real_pte_t pte, int psize,
-			    int local);
+			    int ssize, int local);
 extern void flush_hash_range(unsigned long number, int local);