[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, 13 insertions, 7 deletions

diff --git a/arch/powerpc/mm/tlb_64.c b/arch/powerpc/mm/tlb_64.c
index cbd34fc813ee..eafbca52bff9 100644
--- a/arch/powerpc/mm/tlb_64.c
+++ b/arch/powerpc/mm/tlb_64.c
@@ -132,6 +132,7 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 	struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
 	unsigned long vsid, vaddr;
 	unsigned int psize;
+	int ssize;
 	real_pte_t rpte;
 	int i;
 
@@ -161,11 +162,14 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 
 	/* Build full vaddr */
 	if (!is_kernel_addr(addr)) {
-		vsid = get_vsid(mm->context.id, addr);
+		ssize = user_segment_size(addr);
+		vsid = get_vsid(mm->context.id, addr, ssize);
 		WARN_ON(vsid == 0);
-	} else
-		vsid = get_kernel_vsid(addr);
-	vaddr = (vsid << 28 ) | (addr & 0x0fffffff);
+	} else {
+		vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+		ssize = mmu_kernel_ssize;
+	}
+	vaddr = hpt_va(addr, vsid, ssize);
 	rpte = __real_pte(__pte(pte), ptep);
 
 	/*
@@ -175,7 +179,7 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 	 * and decide to use local invalidates instead...
 	 */
 	if (!batch->active) {
-		flush_hash_page(vaddr, rpte, psize, 0);
+		flush_hash_page(vaddr, rpte, psize, ssize, 0);
 		return;
 	}
 
@@ -189,13 +193,15 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 	 * We also need to ensure only one page size is present in a given
 	 * batch
 	 */
-	if (i != 0 && (mm != batch->mm || batch->psize != psize)) {
+	if (i != 0 && (mm != batch->mm || batch->psize != psize ||
+		       batch->ssize != ssize)) {
 		__flush_tlb_pending(batch);
 		i = 0;
 	}
 	if (i == 0) {
 		batch->mm = mm;
 		batch->psize = psize;
+		batch->ssize = ssize;
 	}
 	batch->pte[i] = rpte;
 	batch->vaddr[i] = vaddr;
@@ -222,7 +228,7 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
 		local = 1;
 	if (i == 1)
 		flush_hash_page(batch->vaddr[0], batch->pte[0],
-				batch->psize, local);
+				batch->psize, batch->ssize, local);
 	else
 		flush_hash_range(i, local);
 	batch->index = 0;