[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 230 insertions, 147 deletions

diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 174d14576c28..d96bcfe4c6f6 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -9,6 +9,9 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+
+#undef DEBUG_LOW
+
 #include <linux/spinlock.h>
 #include <linux/bitops.h>
 #include <linux/threads.h>
@@ -22,11 +25,84 @@
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
 #include <asm/cputable.h>
+#include <asm/udbg.h>
+
+#ifdef DEBUG_LOW
+#define DBG_LOW(fmt...) udbg_printf(fmt)
+#else
+#define DBG_LOW(fmt...)
+#endif
 
 #define HPTE_LOCK_BIT 3
 
 static DEFINE_SPINLOCK(native_tlbie_lock);
 
+static inline void __tlbie(unsigned long va, unsigned int psize)
+{
+	unsigned int penc;
+
+	/* clear top 16 bits, non SLS segment */
+	va &= ~(0xffffULL << 48);
+
+	switch (psize) {
+	case MMU_PAGE_4K:
+		va &= ~0xffful;
+		asm volatile("tlbie %0,0" : : "r" (va) : "memory");
+		break;
+	default:
+		penc = mmu_psize_defs[psize].penc;
+		va &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
+		va |= (0x7f >> (8 - penc)) << 12;
+		asm volatile("tlbie %0,1" : : "r" (va) : "memory");
+		break;
+	}
+}
+
+static inline void __tlbiel(unsigned long va, unsigned int psize)
+{
+	unsigned int penc;
+
+	/* clear top 16 bits, non SLS segment */
+	va &= ~(0xffffULL << 48);
+
+	switch (psize) {
+	case MMU_PAGE_4K:
+		va &= ~0xffful;
+		asm volatile(".long 0x7c000224 | (%0 << 11) | (0 << 21)"
+			     : : "r"(va) : "memory");
+		break;
+	default:
+		penc = mmu_psize_defs[psize].penc;
+		va &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
+		va |= (0x7f >> (8 - penc)) << 12;
+		asm volatile(".long 0x7c000224 | (%0 << 11) | (1 << 21)"
+			     : : "r"(va) : "memory");
+		break;
+	}
+
+}
+
+static inline void tlbie(unsigned long va, int psize, int local)
+{
+	unsigned int use_local = local && cpu_has_feature(CPU_FTR_TLBIEL);
+	int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
+
+	if (use_local)
+		use_local = mmu_psize_defs[psize].tlbiel;
+	if (lock_tlbie && !use_local)
+		spin_lock(&native_tlbie_lock);
+	asm volatile("ptesync": : :"memory");
+	if (use_local) {
+		__tlbiel(va, psize);
+		asm volatile("ptesync": : :"memory");
+	} else {
+		__tlbie(va, psize);
+		asm volatile("eieio; tlbsync; ptesync": : :"memory");
+	}
+	if (lock_tlbie && !use_local)
+		spin_unlock(&native_tlbie_lock);
+}
+
 static inline void native_lock_hpte(hpte_t *hptep)
 {
 	unsigned long *word = &hptep->v;
@@ -48,13 +124,19 @@ static inline void native_unlock_hpte(hpte_t *hptep)
 }
 
 long native_hpte_insert(unsigned long hpte_group, unsigned long va,
-			unsigned long prpn, unsigned long vflags,
-			unsigned long rflags)
+			unsigned long pa, unsigned long rflags,
+			unsigned long vflags, int psize)
 {
 	hpte_t *hptep = htab_address + hpte_group;
 	unsigned long hpte_v, hpte_r;
 	int i;
 
+	if (!(vflags & HPTE_V_BOLTED)) {
+		DBG_LOW("    insert(group=%lx, va=%016lx, pa=%016lx,"
+			" rflags=%lx, vflags=%lx, psize=%d)\n",
+			hpte_group, va, pa, rflags, vflags, psize);
+	}
+
 	for (i = 0; i < HPTES_PER_GROUP; i++) {
 		if (! (hptep->v & HPTE_V_VALID)) {
 			/* retry with lock held */
@@ -70,10 +152,13 @@ long native_hpte_insert(unsigned long hpte_group, unsigned long va,
 	if (i == HPTES_PER_GROUP)
 		return -1;
 
-	hpte_v = (va >> 23) << HPTE_V_AVPN_SHIFT | vflags | HPTE_V_VALID;
-	if (vflags & HPTE_V_LARGE)
-		va &= ~(1UL << HPTE_V_AVPN_SHIFT);
-	hpte_r = (prpn << HPTE_R_RPN_SHIFT) | rflags;
+	hpte_v = hpte_encode_v(va, psize) | vflags | HPTE_V_VALID;
+	hpte_r = hpte_encode_r(pa, psize) | rflags;
+
+	if (!(vflags & HPTE_V_BOLTED)) {
+		DBG_LOW(" i=%x hpte_v=%016lx, hpte_r=%016lx\n",
+			i, hpte_v, hpte_r);
+	}
 
 	hptep->r = hpte_r;
 	/* Guarantee the second dword is visible before the valid bit */
@@ -96,6 +181,8 @@ static long native_hpte_remove(unsigned long hpte_group)
 	int slot_offset;
 	unsigned long hpte_v;
 
+	DBG_LOW("    remove(group=%lx)\n", hpte_group);
+
 	/* pick a random entry to start at */
 	slot_offset = mftb() & 0x7;
 
@@ -126,34 +213,51 @@ static long native_hpte_remove(unsigned long hpte_group)
 	return i;
 }
 
-static inline void set_pp_bit(unsigned long pp, hpte_t *addr)
+static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
+				 unsigned long va, int psize, int local)
 {
-	unsigned long old;
-	unsigned long *p = &addr->r;
-
-	__asm__ __volatile__(
-	"1:	ldarx	%0,0,%3\n\
-		rldimi	%0,%2,0,61\n\
-		stdcx.	%0,0,%3\n\
-		bne	1b"
-	: "=&r" (old), "=m" (*p)
-	: "r" (pp), "r" (p), "m" (*p)
-	: "cc");
+	hpte_t *hptep = htab_address + slot;
+	unsigned long hpte_v, want_v;
+	int ret = 0;
+
+	want_v = hpte_encode_v(va, psize);
+
+	DBG_LOW("    update(va=%016lx, avpnv=%016lx, hash=%016lx, newpp=%x)",
+		va, want_v & HPTE_V_AVPN, slot, newpp);
+
+	native_lock_hpte(hptep);
+
+	hpte_v = hptep->v;
+
+	/* Even if we miss, we need to invalidate the TLB */
+	if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID)) {
+		DBG_LOW(" -> miss\n");
+		native_unlock_hpte(hptep);
+		ret = -1;
+	} else {
+		DBG_LOW(" -> hit\n");
+		/* Update the HPTE */
+		hptep->r = (hptep->r & ~(HPTE_R_PP | HPTE_R_N)) |
+			(newpp & (HPTE_R_PP | HPTE_R_N));
+		native_unlock_hpte(hptep);
+	}
+
+	/* Ensure it is out of the tlb too. */
+	tlbie(va, psize, local);
+
+	return ret;
 }
 
-/*
- * Only works on small pages. Yes its ugly to have to check each slot in
- * the group but we only use this during bootup.
- */
-static long native_hpte_find(unsigned long vpn)
+static long native_hpte_find(unsigned long va, int psize)
 {
 	hpte_t *hptep;
 	unsigned long hash;
 	unsigned long i, j;
 	long slot;
-	unsigned long hpte_v;
+	unsigned long want_v, hpte_v;
 
-	hash = hpt_hash(vpn, 0);
+	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;
@@ -161,7 +265,7 @@ static long native_hpte_find(unsigned long vpn)
 			hptep = htab_address + slot;
 			hpte_v = hptep->v;
 
-			if ((HPTE_V_AVPN_VAL(hpte_v) == (vpn >> 11))
+			if (HPTE_V_COMPARE(hpte_v, want_v)
 			    && (hpte_v & HPTE_V_VALID)
 			    && ( !!(hpte_v & HPTE_V_SECONDARY) == j)) {
 				/* HPTE matches */
@@ -177,127 +281,101 @@ static long native_hpte_find(unsigned long vpn)
 	return -1;
 }
 
-static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
-				 unsigned long va, int large, int local)
-{
-	hpte_t *hptep = htab_address + slot;
-	unsigned long hpte_v;
-	unsigned long avpn = va >> 23;
-	int ret = 0;
-
-	if (large)
-		avpn &= ~1;
-
-	native_lock_hpte(hptep);
-
-	hpte_v = hptep->v;
-
-	/* Even if we miss, we need to invalidate the TLB */
-	if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
-	    || !(hpte_v & HPTE_V_VALID)) {
-		native_unlock_hpte(hptep);
-		ret = -1;
-	} else {
-		set_pp_bit(newpp, hptep);
-		native_unlock_hpte(hptep);
-	}
-
-	/* Ensure it is out of the tlb too */
-	if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
-		tlbiel(va);
-	} else {
-		int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
-
-		if (lock_tlbie)
-			spin_lock(&native_tlbie_lock);
-		tlbie(va, large);
-		if (lock_tlbie)
-			spin_unlock(&native_tlbie_lock);
-	}
-
-	return ret;
-}
-
 /*
  * Update the page protection bits. Intended to be used to create
  * guard pages for kernel data structures on pages which are bolted
  * in the HPT. Assumes pages being operated on will not be stolen.
- * Does not work on large pages.
  *
  * No need to lock here because we should be the only user.
  */
-static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea)
+static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
+				       int psize)
 {
-	unsigned long vsid, va, vpn, flags = 0;
+	unsigned long vsid, va;
 	long slot;
 	hpte_t *hptep;
-	int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
 
 	vsid = get_kernel_vsid(ea);
 	va = (vsid << 28) | (ea & 0x0fffffff);
-	vpn = va >> PAGE_SHIFT;
 
-	slot = native_hpte_find(vpn);
+	slot = native_hpte_find(va, psize);
 	if (slot == -1)
 		panic("could not find page to bolt\n");
 	hptep = htab_address + slot;
 
-	set_pp_bit(newpp, hptep);
+	/* Update the HPTE */
+	hptep->r = (hptep->r & ~(HPTE_R_PP | HPTE_R_N)) |
+		(newpp & (HPTE_R_PP | HPTE_R_N));
 
-	/* Ensure it is out of the tlb too */
-	if (lock_tlbie)
-		spin_lock_irqsave(&native_tlbie_lock, flags);
-	tlbie(va, 0);
-	if (lock_tlbie)
-		spin_unlock_irqrestore(&native_tlbie_lock, flags);
+	/* Ensure it is out of the tlb too. */
+	tlbie(va, psize, 0);
 }
 
 static void native_hpte_invalidate(unsigned long slot, unsigned long va,
-				    int large, int local)
+				   int psize, int local)
 {
 	hpte_t *hptep = htab_address + slot;
 	unsigned long hpte_v;
-	unsigned long avpn = va >> 23;
+	unsigned long want_v;
 	unsigned long flags;
-	int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
-
-	if (large)
-		avpn &= ~1;
 
 	local_irq_save(flags);
-	native_lock_hpte(hptep);
 
+	DBG_LOW("    invalidate(va=%016lx, hash: %x)\n", va, slot);
+
+	want_v = hpte_encode_v(va, psize);
+	native_lock_hpte(hptep);
 	hpte_v = hptep->v;
 
 	/* Even if we miss, we need to invalidate the TLB */
-	if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
-	    || !(hpte_v & HPTE_V_VALID)) {
+	if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
 		native_unlock_hpte(hptep);
-	} else {
+	else
 		/* Invalidate the hpte. NOTE: this also unlocks it */
 		hptep->v = 0;
-	}
 
-	/* Invalidate the tlb */
-	if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
-		tlbiel(va);
-	} else {
-		if (lock_tlbie)
-			spin_lock(&native_tlbie_lock);
-		tlbie(va, large);
-		if (lock_tlbie)
-			spin_unlock(&native_tlbie_lock);
-	}
+	/* Invalidate the TLB */
+	tlbie(va, psize, local);
+
 	local_irq_restore(flags);
 }
 
 /*
+ * XXX This need fixing based on page size. It's only used by
+ * native_hpte_clear() for now which needs fixing too so they
+ * make a good pair...
+ */
+static unsigned long slot2va(unsigned long hpte_v, unsigned long slot)
+{
+	unsigned long avpn = HPTE_V_AVPN_VAL(hpte_v);
+	unsigned long va;
+
+	va = avpn << 23;
+
+	if (! (hpte_v & HPTE_V_LARGE)) {
+		unsigned long vpi, pteg;
+
+		pteg = slot / HPTES_PER_GROUP;
+		if (hpte_v & HPTE_V_SECONDARY)
+			pteg = ~pteg;
+
+		vpi = ((va >> 28) ^ pteg) & htab_hash_mask;
+
+		va |= vpi << PAGE_SHIFT;
+	}
+
+	return va;
+}
+
+/*
  * clear all mappings on kexec.  All cpus are in real mode (or they will
  * be when they isi), and we are the only one left.  We rely on our kernel
  * mapping being 0xC0's and the hardware ignoring those two real bits.
  *
  * TODO: add batching support when enabled.  remember, no dynamic memory here,
  * athough there is the control page available...
+ *
+ * XXX FIXME: 4k only for now !
  */
 static void native_hpte_clear(void)
 {
@@ -327,7 +405,7 @@ static void native_hpte_clear(void)
 
 		if (hpte_v & HPTE_V_VALID) {
 			hptep->v = 0;
-			tlbie(slot2va(hpte_v, slot), hpte_v & HPTE_V_LARGE);
+			tlbie(slot2va(hpte_v, slot), MMU_PAGE_4K, 0);
 		}
 	}
 
@@ -335,59 +413,59 @@ static void native_hpte_clear(void)
 	local_irq_restore(flags);
 }
 
+/*
+ * Batched hash table flush, we batch the tlbie's to avoid taking/releasing
+ * the lock all the time
+ */
 static void native_flush_hash_range(unsigned long number, int local)
 {
-	unsigned long va, vpn, hash, secondary, slot, flags, avpn;
-	int i, j;
+	unsigned long va, hash, index, hidx, shift, slot;
 	hpte_t *hptep;
 	unsigned long hpte_v;
+	unsigned long want_v;
+	unsigned long flags;
+	real_pte_t pte;
 	struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
-	unsigned long large = batch->large;
+	unsigned long psize = batch->psize;
+	int i;
 
 	local_irq_save(flags);
 
-	j = 0;
 	for (i = 0; i < number; i++) {
-		va = batch->vaddr[j];
-		if (large)
-			vpn = va >> HPAGE_SHIFT;
-		else
-			vpn = va >> PAGE_SHIFT;
-		hash = hpt_hash(vpn, large);
-		secondary = (pte_val(batch->pte[i]) & _PAGE_SECONDARY) >> 15;
-		if (secondary)
-			hash = ~hash;
-		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
-		slot += (pte_val(batch->pte[i]) & _PAGE_GROUP_IX) >> 12;
-
-		hptep = htab_address + slot;
-
-		avpn = va >> 23;
-		if (large)
-			avpn &= ~0x1UL;
-
-		native_lock_hpte(hptep);
-
-		hpte_v = hptep->v;
-
-		/* Even if we miss, we need to invalidate the TLB */
-		if ((HPTE_V_AVPN_VAL(hpte_v) != avpn)
-		    || !(hpte_v & HPTE_V_VALID)) {
-			native_unlock_hpte(hptep);
-		} else {
-			/* Invalidate the hpte. NOTE: this also unlocks it */
-			hptep->v = 0;
-		}
-
-		j++;
+		va = batch->vaddr[i];
+		pte = batch->pte[i];
+
+		pte_iterate_hashed_subpages(pte, psize, va, index, shift) {
+			hash = hpt_hash(va, shift);
+			hidx = __rpte_to_hidx(pte, index);
+			if (hidx & _PTEIDX_SECONDARY)
+				hash = ~hash;
+			slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+			slot += hidx & _PTEIDX_GROUP_IX;
+			hptep = htab_address + slot;
+			want_v = hpte_encode_v(va, psize);
+			native_lock_hpte(hptep);
+			hpte_v = hptep->v;
+			if (!HPTE_V_COMPARE(hpte_v, want_v) ||
+			    !(hpte_v & HPTE_V_VALID))
+				native_unlock_hpte(hptep);
+			else
+				hptep->v = 0;
+		} pte_iterate_hashed_end();
 	}
 
-	if (cpu_has_feature(CPU_FTR_TLBIEL) && !large && local) {
+	if (cpu_has_feature(CPU_FTR_TLBIEL) &&
+	    mmu_psize_defs[psize].tlbiel && local) {
 		asm volatile("ptesync":::"memory");
-
-		for (i = 0; i < j; i++)
-			__tlbiel(batch->vaddr[i]);
-
+		for (i = 0; i < number; i++) {
+			va = batch->vaddr[i];
+			pte = batch->pte[i];
+
+			pte_iterate_hashed_subpages(pte, psize, va, index,
+						    shift) {
+				__tlbiel(va, psize);
+			} pte_iterate_hashed_end();
+		}
 		asm volatile("ptesync":::"memory");
 	} else {
 		int lock_tlbie = !cpu_has_feature(CPU_FTR_LOCKLESS_TLBIE);
@@ -396,10 +474,15 @@ static void native_flush_hash_range(unsigned long number, int local)
 			spin_lock(&native_tlbie_lock);
 
 		asm volatile("ptesync":::"memory");
-
-		for (i = 0; i < j; i++)
-			__tlbie(batch->vaddr[i], large);
-
+		for (i = 0; i < number; i++) {
+			va = batch->vaddr[i];
+			pte = batch->pte[i];
+
+			pte_iterate_hashed_subpages(pte, psize, va, index,
+						    shift) {
+				__tlbie(va, psize);
+			} pte_iterate_hashed_end();
+		}
 		asm volatile("eieio; tlbsync; ptesync":::"memory");
 
 		if (lock_tlbie)