[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, 49 insertions, 40 deletions

diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index ea327ca345c..9a455d46379 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -284,7 +284,7 @@ void vpa_init(int cpu)
 static long pSeries_lpar_hpte_insert(unsigned long hpte_group,
  			      unsigned long va, unsigned long pa,
  			      unsigned long rflags, unsigned long vflags,
- 			      int psize)
+			      int psize, int ssize)
 {
 	unsigned long lpar_rc;
 	unsigned long flags;
@@ -296,7 +296,7 @@ static long pSeries_lpar_hpte_insert(unsigned long hpte_group,
 			"rflags=%lx, vflags=%lx, psize=%d)\n",
 		hpte_group, va, pa, rflags, vflags, psize);
 
- 	hpte_v = hpte_encode_v(va, psize) | vflags | HPTE_V_VALID;
+	hpte_v = hpte_encode_v(va, psize, ssize) | vflags | HPTE_V_VALID;
 	hpte_r = hpte_encode_r(pa, psize) | rflags;
 
 	if (!(vflags & HPTE_V_BOLTED))
@@ -392,6 +392,22 @@ static void pSeries_lpar_hptab_clear(void)
 }
 
 /*
+ * This computes the AVPN and B fields of the first dword of a HPTE,
+ * for use when we want to match an existing PTE.  The bottom 7 bits
+ * of the returned value are zero.
+ */
+static inline unsigned long hpte_encode_avpn(unsigned long va, int psize,
+					     int ssize)
+{
+	unsigned long v;
+
+	v = (va >> 23) & ~(mmu_psize_defs[psize].avpnm);
+	v <<= HPTE_V_AVPN_SHIFT;
+	v |= ((unsigned long) ssize) << HPTE_V_SSIZE_SHIFT;
+	return v;
+}
+
+/*
  * NOTE: for updatepp ops we are fortunate that the linux "newpp" bits and
  * the low 3 bits of flags happen to line up.  So no transform is needed.
  * We can probably optimize here and assume the high bits of newpp are
@@ -400,18 +416,18 @@ static void pSeries_lpar_hptab_clear(void)
 static long pSeries_lpar_hpte_updatepp(unsigned long slot,
 				       unsigned long newpp,
 				       unsigned long va,
-				       int psize, int local)
+				       int psize, int ssize, int local)
 {
 	unsigned long lpar_rc;
 	unsigned long flags = (newpp & 7) | H_AVPN;
 	unsigned long want_v;
 
-	want_v = hpte_encode_v(va, psize);
+	want_v = hpte_encode_avpn(va, psize, ssize);
 
 	DBG_LOW("    update: avpnv=%016lx, hash=%016lx, f=%x, psize: %d ... ",
-		want_v & HPTE_V_AVPN, slot, flags, psize);
+		want_v, slot, flags, psize);
 
-	lpar_rc = plpar_pte_protect(flags, slot, want_v & HPTE_V_AVPN);
+	lpar_rc = plpar_pte_protect(flags, slot, want_v);
 
 	if (lpar_rc == H_NOT_FOUND) {
 		DBG_LOW("not found !\n");
@@ -444,32 +460,25 @@ static unsigned long pSeries_lpar_hpte_getword0(unsigned long slot)
 	return dword0;
 }
 
-static long pSeries_lpar_hpte_find(unsigned long va, int psize)
+static long pSeries_lpar_hpte_find(unsigned long va, int psize, int ssize)
 {
 	unsigned long hash;
-	unsigned long i, j;
+	unsigned long i;
 	long slot;
 	unsigned long want_v, hpte_v;
 
-	hash = hpt_hash(va, mmu_psize_defs[psize].shift);
-	want_v = hpte_encode_v(va, psize);
-
-	for (j = 0; j < 2; j++) {
-		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
-		for (i = 0; i < HPTES_PER_GROUP; i++) {
-			hpte_v = pSeries_lpar_hpte_getword0(slot);
-
-			if (HPTE_V_COMPARE(hpte_v, want_v)
-			    && (hpte_v & HPTE_V_VALID)
-			    && (!!(hpte_v & HPTE_V_SECONDARY) == j)) {
-				/* HPTE matches */
-				if (j)
-					slot = -slot;
-				return slot;
-			}
-			++slot;
-		}
-		hash = ~hash;
+	hash = hpt_hash(va, mmu_psize_defs[psize].shift, ssize);
+	want_v = hpte_encode_avpn(va, psize, ssize);
+
+	/* Bolted entries are always in the primary group */
+	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+	for (i = 0; i < HPTES_PER_GROUP; i++) {
+		hpte_v = pSeries_lpar_hpte_getword0(slot);
+
+		if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID))
+			/* HPTE matches */
+			return slot;
+		++slot;
 	}
 
 	return -1;
@@ -477,14 +486,14 @@ static long pSeries_lpar_hpte_find(unsigned long va, int psize)
 
 static void pSeries_lpar_hpte_updateboltedpp(unsigned long newpp,
 					     unsigned long ea,
-					     int psize)
+					     int psize, int ssize)
 {
 	unsigned long lpar_rc, slot, vsid, va, flags;
 
-	vsid = get_kernel_vsid(ea);
-	va = (vsid << 28) | (ea & 0x0fffffff);
+	vsid = get_kernel_vsid(ea, ssize);
+	va = hpt_va(ea, vsid, ssize);
 
-	slot = pSeries_lpar_hpte_find(va, psize);
+	slot = pSeries_lpar_hpte_find(va, psize, ssize);
 	BUG_ON(slot == -1);
 
 	flags = newpp & 7;
@@ -494,7 +503,7 @@ static void pSeries_lpar_hpte_updateboltedpp(unsigned long newpp,
 }
 
 static void pSeries_lpar_hpte_invalidate(unsigned long slot, unsigned long va,
-					 int psize, int local)
+					 int psize, int ssize, int local)
 {
 	unsigned long want_v;
 	unsigned long lpar_rc;
@@ -503,9 +512,8 @@ static void pSeries_lpar_hpte_invalidate(unsigned long slot, unsigned long va,
 	DBG_LOW("    inval : slot=%lx, va=%016lx, psize: %d, local: %d",
 		slot, va, psize, local);
 
-	want_v = hpte_encode_v(va, psize);
-	lpar_rc = plpar_pte_remove(H_AVPN, slot, want_v & HPTE_V_AVPN,
-				   &dummy1, &dummy2);
+	want_v = hpte_encode_avpn(va, psize, ssize);
+	lpar_rc = plpar_pte_remove(H_AVPN, slot, want_v, &dummy1, &dummy2);
 	if (lpar_rc == H_NOT_FOUND)
 		return;
 
@@ -533,18 +541,19 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
 	unsigned long va;
 	unsigned long hash, index, shift, hidx, slot;
 	real_pte_t pte;
-	int psize;
+	int psize, ssize;
 
 	if (lock_tlbie)
 		spin_lock_irqsave(&pSeries_lpar_tlbie_lock, flags);
 
 	psize = batch->psize;
+	ssize = batch->ssize;
 	pix = 0;
 	for (i = 0; i < number; i++) {
 		va = batch->vaddr[i];
 		pte = batch->pte[i];
 		pte_iterate_hashed_subpages(pte, psize, va, index, shift) {
-			hash = hpt_hash(va, shift);
+			hash = hpt_hash(va, shift, ssize);
 			hidx = __rpte_to_hidx(pte, index);
 			if (hidx & _PTEIDX_SECONDARY)
 				hash = ~hash;
@@ -552,11 +561,11 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
 			slot += hidx & _PTEIDX_GROUP_IX;
 			if (!firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
 				pSeries_lpar_hpte_invalidate(slot, va, psize,
-							     local);
+							     ssize, local);
 			} else {
 				param[pix] = HBR_REQUEST | HBR_AVPN | slot;
-				param[pix+1] = hpte_encode_v(va, psize) &
-					HPTE_V_AVPN;
+				param[pix+1] = hpte_encode_avpn(va, psize,
+								ssize);
 				pix += 2;
 				if (pix == 8) {
 					rc = plpar_hcall9(H_BULK_REMOVE, param,