powerpc: Decode the pte-lp-encoding bits correctly.

We look at both the segment base page size and actual page size and store
the pte-lp-encodings in an array per base page size.

We also update all relevant functions to take actual page size argument
so that we can use the correct PTE LP encoding in HPTE. This should also
get the basic Multiple Page Size per Segment (MPSS) support. This is needed
to enable THP on ppc64.

[Fixed PR KVM build --BenH]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 81 insertions, 44 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 1ed4419c533..cd75d68a730 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -126,7 +126,7 @@ static struct mmu_psize_def mmu_psize_defaults_old[] = {
 	[MMU_PAGE_4K] = {
 		.shift	= 12,
 		.sllp	= 0,
-		.penc	= 0,
+		.penc   = {[MMU_PAGE_4K] = 0, [1 ... MMU_PAGE_COUNT - 1] = -1},
 		.avpnm	= 0,
 		.tlbiel = 0,
 	},
@@ -140,14 +140,15 @@ static struct mmu_psize_def mmu_psize_defaults_gp[] = {
 	[MMU_PAGE_4K] = {
 		.shift	= 12,
 		.sllp	= 0,
-		.penc	= 0,
+		.penc   = {[MMU_PAGE_4K] = 0, [1 ... MMU_PAGE_COUNT - 1] = -1},
 		.avpnm	= 0,
 		.tlbiel = 1,
 	},
 	[MMU_PAGE_16M] = {
 		.shift	= 24,
 		.sllp	= SLB_VSID_L,
-		.penc	= 0,
+		.penc   = {[0 ... MMU_PAGE_16M - 1] = -1, [MMU_PAGE_16M] = 0,
+			    [MMU_PAGE_16M + 1 ... MMU_PAGE_COUNT - 1] = -1 },
 		.avpnm	= 0x1UL,
 		.tlbiel = 0,
 	},
@@ -209,7 +210,7 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 
 		BUG_ON(!ppc_md.hpte_insert);
 		ret = ppc_md.hpte_insert(hpteg, vpn, paddr, tprot,
-					 HPTE_V_BOLTED, psize, ssize);
+					 HPTE_V_BOLTED, psize, psize, ssize);
 
 		if (ret < 0)
 			break;
@@ -276,6 +277,30 @@ static void __init htab_init_seg_sizes(void)
 	of_scan_flat_dt(htab_dt_scan_seg_sizes, NULL);
 }
 
+static int __init get_idx_from_shift(unsigned int shift)
+{
+	int idx = -1;
+
+	switch (shift) {
+	case 0xc:
+		idx = MMU_PAGE_4K;
+		break;
+	case 0x10:
+		idx = MMU_PAGE_64K;
+		break;
+	case 0x14:
+		idx = MMU_PAGE_1M;
+		break;
+	case 0x18:
+		idx = MMU_PAGE_16M;
+		break;
+	case 0x22:
+		idx = MMU_PAGE_16G;
+		break;
+	}
+	return idx;
+}
+
 static int __init htab_dt_scan_page_sizes(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
@@ -295,60 +320,61 @@ static int __init htab_dt_scan_page_sizes(unsigned long node,
 		size /= 4;
 		cur_cpu_spec->mmu_features &= ~(MMU_FTR_16M_PAGE);
 		while(size > 0) {
-			unsigned int shift = prop[0];
+			unsigned int base_shift = prop[0];
 			unsigned int slbenc = prop[1];
 			unsigned int lpnum = prop[2];
-			unsigned int lpenc = 0;
 			struct mmu_psize_def *def;
-			int idx = -1;
+			int idx, base_idx;
 
 			size -= 3; prop += 3;
-			while(size > 0 && lpnum) {
-				if (prop[0] == shift)
-					lpenc = prop[1];
-				prop += 2; size -= 2;
-				lpnum--;
+			base_idx = get_idx_from_shift(base_shift);
+			if (base_idx < 0) {
+				/*
+				 * skip the pte encoding also
+				 */
+				prop += lpnum * 2; size -= lpnum * 2;
+				continue;
 			}
-			switch(shift) {
-			case 0xc:
-				idx = MMU_PAGE_4K;
-				break;
-			case 0x10:
-				idx = MMU_PAGE_64K;
-				break;
-			case 0x14:
-				idx = MMU_PAGE_1M;
-				break;
-			case 0x18:
-				idx = MMU_PAGE_16M;
+			def = &mmu_psize_defs[base_idx];
+			if (base_idx == MMU_PAGE_16M)
 				cur_cpu_spec->mmu_features |= MMU_FTR_16M_PAGE;
-				break;
-			case 0x22:
-				idx = MMU_PAGE_16G;
-				break;
-			}
-			if (idx < 0)
-				continue;
-			def = &mmu_psize_defs[idx];
-			def->shift = shift;
-			if (shift <= 23)
+
+			def->shift = base_shift;
+			if (base_shift <= 23)
 				def->avpnm = 0;
 			else
-				def->avpnm = (1 << (shift - 23)) - 1;
+				def->avpnm = (1 << (base_shift - 23)) - 1;
 			def->sllp = slbenc;
-			def->penc = lpenc;
-			/* We don't know for sure what's up with tlbiel, so
+			/*
+			 * We don't know for sure what's up with tlbiel, so
 			 * for now we only set it for 4K and 64K pages
 			 */
-			if (idx == MMU_PAGE_4K || idx == MMU_PAGE_64K)
+			if (base_idx == MMU_PAGE_4K || base_idx == MMU_PAGE_64K)
 				def->tlbiel = 1;
 			else
 				def->tlbiel = 0;
 
-			DBG(" %d: shift=%02x, sllp=%04lx, avpnm=%08lx, "
-			    "tlbiel=%d, penc=%d\n",
-			    idx, shift, def->sllp, def->avpnm, def->tlbiel,
-			    def->penc);
+			while (size > 0 && lpnum) {
+				unsigned int shift = prop[0];
+				int penc  = prop[1];
+
+				prop += 2; size -= 2;
+				lpnum--;
+
+				idx = get_idx_from_shift(shift);
+				if (idx < 0)
+					continue;
+
+				if (penc == -1)
+					pr_err("Invalid penc for base_shift=%d "
+					       "shift=%d\n", base_shift, shift);
+
+				def->penc[idx] = penc;
+				DBG(" %d: shift=%02x, sllp=%04lx, "
+				    "avpnm=%08lx, tlbiel=%d, penc=%d\n",
+				    idx, shift, def->sllp, def->avpnm,
+				    def->tlbiel, def->penc[idx]);
+			}
 		}
 		return 1;
 	}
@@ -397,10 +423,21 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
 }
 #endif /* CONFIG_HUGETLB_PAGE */
 
+static void mmu_psize_set_default_penc(void)
+{
+	int bpsize, apsize;
+	for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++)
+		for (apsize = 0; apsize < MMU_PAGE_COUNT; apsize++)
+			mmu_psize_defs[bpsize].penc[apsize] = -1;
+}
+
 static void __init htab_init_page_sizes(void)
 {
 	int rc;
 
+	/* se the invalid penc to -1 */
+	mmu_psize_set_default_penc();
+
 	/* Default to 4K pages only */
 	memcpy(mmu_psize_defs, mmu_psize_defaults_old,
 	       sizeof(mmu_psize_defaults_old));
@@ -1243,7 +1280,7 @@ repeat:
 
 	/* Insert into the hash table, primary slot */
 	slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, vflags,
-				  psize, ssize);
+				  psize, psize, ssize);
 
 	/* Primary is full, try the secondary */
 	if (unlikely(slot == -1)) {
@@ -1251,7 +1288,7 @@ repeat:
 			      HPTES_PER_GROUP) & ~0x7UL;
 		slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags,
 					  vflags | HPTE_V_SECONDARY,
-					  psize, ssize);
+					  psize, psize, ssize);
 		if (slot == -1) {
 			if (mftb() & 0x1)
 				hpte_group = ((hash & htab_hash_mask) *