arch/powerpc/mm/hash_native_64.c - maze/linux - Git at Google

 /*
  * native hashtable management.
  *
  * SMP scalability work:
  *    Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * 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>
 #include <linux/smp.h>

 #include <asm/abs_addr.h>
 #include <asm/machdep.h>
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
 #include <asm/cputable.h>
 #include <asm/udbg.h>
 #include <asm/kexec.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 |= 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 |= 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(struct hash_pte *hptep)
 {
 	unsigned long *word = &hptep->v;

 	while (1) {
 		if (!test_and_set_bit(HPTE_LOCK_BIT, word))
 			break;
 		while(test_bit(HPTE_LOCK_BIT, word))
 			cpu_relax();
 	}
 }

 static inline void native_unlock_hpte(struct hash_pte *hptep)
 {
 	unsigned long *word = &hptep->v;

 	asm volatile("lwsync":::"memory");
 	clear_bit(HPTE_LOCK_BIT, word);
 }

 static long native_hpte_insert(unsigned long hpte_group, unsigned long va,
 			unsigned long pa, unsigned long rflags,
 			unsigned long vflags, int psize)
 {
 	struct hash_pte *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 */
 			native_lock_hpte(hptep);
 			if (! (hptep->v & HPTE_V_VALID))
 				break;
 			native_unlock_hpte(hptep);
 		}

 		hptep++;
 	}

 	if (i == HPTES_PER_GROUP)
 		return -1;

 	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 */
 	__asm__ __volatile__ ("eieio" : : : "memory");
 	/*
 	 * Now set the first dword including the valid bit
 	 * NOTE: this also unlocks the hpte
 	 */
 	hptep->v = hpte_v;

 	__asm__ __volatile__ ("ptesync" : : : "memory");

 	return i | (!!(vflags & HPTE_V_SECONDARY) << 3);
 }

 static long native_hpte_remove(unsigned long hpte_group)
 {
 	struct hash_pte *hptep;
 	int i;
 	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;

 	for (i = 0; i < HPTES_PER_GROUP; i++) {
 		hptep = htab_address + hpte_group + slot_offset;
 		hpte_v = hptep->v;

 		if ((hpte_v & HPTE_V_VALID) && !(hpte_v & HPTE_V_BOLTED)) {
 			/* retry with lock held */
 			native_lock_hpte(hptep);
 			hpte_v = hptep->v;
 			if ((hpte_v & HPTE_V_VALID)
 			    && !(hpte_v & HPTE_V_BOLTED))
 				break;
 			native_unlock_hpte(hptep);
 		}

 		slot_offset++;
 		slot_offset &= 0x7;
 	}

 	if (i == HPTES_PER_GROUP)
 		return -1;

 	/* Invalidate the hpte. NOTE: this also unlocks it */
 	hptep->v = 0;

 	return i;
 }

 static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
 				 unsigned long va, int psize, int local)
 {
 	struct hash_pte *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");
 		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 | HPTE_R_C));
 	}
 	native_unlock_hpte(hptep);

 	/* Ensure it is out of the tlb too. */
 	tlbie(va, psize, local);

 	return ret;
 }

 static long native_hpte_find(unsigned long va, int psize)
 {
 	struct hash_pte *hptep;
 	unsigned long hash;
 	unsigned long i, j;
 	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++) {
 			hptep = htab_address + slot;
 			hpte_v = hptep->v;

 			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;
 	}

 	return -1;
 }

 /*
  * 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.
  *
  * No need to lock here because we should be the only user.
  */
 static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
 				       int psize)
 {
 	unsigned long vsid, va;
 	long slot;
 	struct hash_pte *hptep;

 	vsid = get_kernel_vsid(ea);
 	va = (vsid << 28) | (ea & 0x0fffffff);

 	slot = native_hpte_find(va, psize);
 	if (slot == -1)
 		panic("could not find page to bolt\n");
 	hptep = htab_address + slot;

 	/* 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. */
 	tlbie(va, psize, 0);
 }

 static void native_hpte_invalidate(unsigned long slot, unsigned long va,
 				   int psize, int local)
 {
 	struct hash_pte *hptep = htab_address + slot;
 	unsigned long hpte_v;
 	unsigned long want_v;
 	unsigned long flags;

 	local_irq_save(flags);

 	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_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
 		native_unlock_hpte(hptep);
 	else
 		/* Invalidate the hpte. NOTE: this also unlocks it */
 		hptep->v = 0;

 	/* Invalidate the TLB */
 	tlbie(va, psize, local);

 	local_irq_restore(flags);
 }

 #define LP_SHIFT	12
 #define LP_BITS		8
 #define LP_MASK(i)	((0xFF >> (i)) << LP_SHIFT)

 static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
 			int *psize, unsigned long *va)
 {
 	unsigned long hpte_r = hpte->r;
 	unsigned long hpte_v = hpte->v;
 	unsigned long avpn;
 	int i, size, shift, penc;

 	if (!(hpte_v & HPTE_V_LARGE))
 		size = MMU_PAGE_4K;
 	else {
 		for (i = 0; i < LP_BITS; i++) {
 			if ((hpte_r & LP_MASK(i+1)) == LP_MASK(i+1))
 				break;
 		}
 		penc = LP_MASK(i+1) >> LP_SHIFT;
 		for (size = 0; size < MMU_PAGE_COUNT; size++) {

 			/* 4K pages are not represented by LP */
 			if (size == MMU_PAGE_4K)
 				continue;

 			/* valid entries have a shift value */
 			if (!mmu_psize_defs[size].shift)
 				continue;

 			if (penc == mmu_psize_defs[size].penc)
 				break;
 		}
 	}

 	/* This works for all page sizes, and for 256M and 1T segments */
 	shift = mmu_psize_defs[size].shift;
 	avpn = (HPTE_V_AVPN_VAL(hpte_v) & ~mmu_psize_defs[size].avpnm) << 23;

 	if (shift < 23) {
 		unsigned long vpi, vsid, pteg;

 		pteg = slot / HPTES_PER_GROUP;
 		if (hpte_v & HPTE_V_SECONDARY)
 			pteg = ~pteg;
 		switch (hpte_v >> HPTE_V_SSIZE_SHIFT) {
 		case MMU_SEGSIZE_256M:
 			vpi = ((avpn >> 28) ^ pteg) & htab_hash_mask;
 			break;
 		case MMU_SEGSIZE_1T:
 			vsid = avpn >> 40;
 			vpi = (vsid ^ (vsid << 25) ^ pteg) & htab_hash_mask;
 			break;
 		default:
 			avpn = vpi = size = 0;
 		}
 		avpn |= (vpi << mmu_psize_defs[size].shift);
 	}

 	*va = avpn;
 	*psize = size;
 }

 /*
  * 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...
  */
 static void native_hpte_clear(void)
 {
 	unsigned long slot, slots, flags;
 	struct hash_pte *hptep = htab_address;
 	unsigned long hpte_v, va;
 	unsigned long pteg_count;
 	int psize;

 	pteg_count = htab_hash_mask + 1;

 	local_irq_save(flags);

 	/* we take the tlbie lock and hold it.  Some hardware will
 	 * deadlock if we try to tlbie from two processors at once.
 	 */
 	spin_lock(&native_tlbie_lock);

 	slots = pteg_count * HPTES_PER_GROUP;

 	for (slot = 0; slot < slots; slot++, hptep++) {
 		/*
 		 * we could lock the pte here, but we are the only cpu
 		 * running,  right?  and for crash dump, we probably
 		 * don't want to wait for a maybe bad cpu.
 		 */
 		hpte_v = hptep->v;

 		/*
 		 * Call __tlbie() here rather than tlbie() since we
 		 * already hold the native_tlbie_lock.
 		 */
 		if (hpte_v & HPTE_V_VALID) {
 			hpte_decode(hptep, slot, &psize, &va);
 			hptep->v = 0;
 			__tlbie(va, psize);
 		}
 	}

 	asm volatile("eieio; tlbsync; ptesync":::"memory");
 	spin_unlock(&native_tlbie_lock);
 	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, hash, index, hidx, shift, slot;
 	struct hash_pte *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 psize = batch->psize;
 	int i;

 	local_irq_save(flags);

 	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);
 			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) &&
 	    mmu_psize_defs[psize].tlbiel && local) {
 		asm volatile("ptesync":::"memory");
 		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);

 		if (lock_tlbie)
 			spin_lock(&native_tlbie_lock);

 		asm volatile("ptesync":::"memory");
 		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)
 			spin_unlock(&native_tlbie_lock);
 	}

 	local_irq_restore(flags);
 }

 #ifdef CONFIG_PPC_PSERIES
 /* Disable TLB batching on nighthawk */
 static inline int tlb_batching_enabled(void)
 {
 	struct device_node *root = of_find_node_by_path("/");
 	int enabled = 1;

 	if (root) {
 		const char *model = of_get_property(root, "model", NULL);
 		if (model && !strcmp(model, "IBM,9076-N81"))
 			enabled = 0;
 		of_node_put(root);
 	}

 	return enabled;
 }
 #else
 static inline int tlb_batching_enabled(void)
 {
 	return 1;
 }
 #endif

 void __init hpte_init_native(void)
 {
 	ppc_md.hpte_invalidate	= native_hpte_invalidate;
 	ppc_md.hpte_updatepp	= native_hpte_updatepp;
 	ppc_md.hpte_updateboltedpp = native_hpte_updateboltedpp;
 	ppc_md.hpte_insert	= native_hpte_insert;
 	ppc_md.hpte_remove	= native_hpte_remove;
 	ppc_md.hpte_clear_all	= native_hpte_clear;
 	if (tlb_batching_enabled())
 		ppc_md.flush_hash_range = native_flush_hash_range;
 }
	/*
	* native hashtable management.
	*
	* SMP scalability work:
	* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* 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>
	#include <linux/smp.h>

	#include <asm/abs_addr.h>
	#include <asm/machdep.h>
	#include <asm/mmu.h>
	#include <asm/mmu_context.h>
	#include <asm/pgtable.h>
	#include <asm/tlbflush.h>
	#include <asm/tlb.h>
	#include <asm/cputable.h>
	#include <asm/udbg.h>
	#include <asm/kexec.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 \|= 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 \|= 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(struct hash_pte *hptep)
	{
	unsigned long *word = &hptep->v;

	while (1) {
	if (!test_and_set_bit(HPTE_LOCK_BIT, word))
	break;
	while(test_bit(HPTE_LOCK_BIT, word))
	cpu_relax();
	}
	}

	static inline void native_unlock_hpte(struct hash_pte *hptep)
	{
	unsigned long *word = &hptep->v;

	asm volatile("lwsync":::"memory");
	clear_bit(HPTE_LOCK_BIT, word);
	}

	static long native_hpte_insert(unsigned long hpte_group, unsigned long va,
	unsigned long pa, unsigned long rflags,
	unsigned long vflags, int psize)
	{
	struct hash_pte *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 */
	native_lock_hpte(hptep);
	if (! (hptep->v & HPTE_V_VALID))
	break;
	native_unlock_hpte(hptep);
	}

	hptep++;
	}

	if (i == HPTES_PER_GROUP)
	return -1;

	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 */
	__asm__ __volatile__ ("eieio" : : : "memory");
	/*
	* Now set the first dword including the valid bit
	* NOTE: this also unlocks the hpte
	*/
	hptep->v = hpte_v;

	__asm__ __volatile__ ("ptesync" : : : "memory");

	return i \| (!!(vflags & HPTE_V_SECONDARY) << 3);
	}

	static long native_hpte_remove(unsigned long hpte_group)
	{
	struct hash_pte *hptep;
	int i;
	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;

	for (i = 0; i < HPTES_PER_GROUP; i++) {
	hptep = htab_address + hpte_group + slot_offset;
	hpte_v = hptep->v;

	if ((hpte_v & HPTE_V_VALID) && !(hpte_v & HPTE_V_BOLTED)) {
	/* retry with lock held */
	native_lock_hpte(hptep);
	hpte_v = hptep->v;
	if ((hpte_v & HPTE_V_VALID)
	&& !(hpte_v & HPTE_V_BOLTED))
	break;
	native_unlock_hpte(hptep);
	}

	slot_offset++;
	slot_offset &= 0x7;
	}

	if (i == HPTES_PER_GROUP)
	return -1;

	/* Invalidate the hpte. NOTE: this also unlocks it */
	hptep->v = 0;

	return i;
	}

	static long native_hpte_updatepp(unsigned long slot, unsigned long newpp,
	unsigned long va, int psize, int local)
	{
	struct hash_pte *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");
	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 \| HPTE_R_C));
	}
	native_unlock_hpte(hptep);

	/* Ensure it is out of the tlb too. */
	tlbie(va, psize, local);

	return ret;
	}

	static long native_hpte_find(unsigned long va, int psize)
	{
	struct hash_pte *hptep;
	unsigned long hash;
	unsigned long i, j;
	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++) {
	hptep = htab_address + slot;
	hpte_v = hptep->v;

	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;
	}

	return -1;
	}

	/*
	* 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.
	*
	* No need to lock here because we should be the only user.
	*/
	static void native_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
	int psize)
	{
	unsigned long vsid, va;
	long slot;
	struct hash_pte *hptep;

	vsid = get_kernel_vsid(ea);
	va = (vsid << 28) \| (ea & 0x0fffffff);

	slot = native_hpte_find(va, psize);
	if (slot == -1)
	panic("could not find page to bolt\n");
	hptep = htab_address + slot;

	/* 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. */
	tlbie(va, psize, 0);
	}

	static void native_hpte_invalidate(unsigned long slot, unsigned long va,
	int psize, int local)
	{
	struct hash_pte *hptep = htab_address + slot;
	unsigned long hpte_v;
	unsigned long want_v;
	unsigned long flags;

	local_irq_save(flags);

	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_COMPARE(hpte_v, want_v) \|\| !(hpte_v & HPTE_V_VALID))
	native_unlock_hpte(hptep);
	else
	/* Invalidate the hpte. NOTE: this also unlocks it */
	hptep->v = 0;

	/* Invalidate the TLB */
	tlbie(va, psize, local);

	local_irq_restore(flags);
	}

	#define LP_SHIFT 12
	#define LP_BITS 8
	#define LP_MASK(i) ((0xFF >> (i)) << LP_SHIFT)

	static void hpte_decode(struct hash_pte *hpte, unsigned long slot,
	int psize, unsigned long va)
	{
	unsigned long hpte_r = hpte->r;
	unsigned long hpte_v = hpte->v;
	unsigned long avpn;
	int i, size, shift, penc;

	if (!(hpte_v & HPTE_V_LARGE))
	size = MMU_PAGE_4K;
	else {
	for (i = 0; i < LP_BITS; i++) {
	if ((hpte_r & LP_MASK(i+1)) == LP_MASK(i+1))
	break;
	}
	penc = LP_MASK(i+1) >> LP_SHIFT;
	for (size = 0; size < MMU_PAGE_COUNT; size++) {

	/* 4K pages are not represented by LP */
	if (size == MMU_PAGE_4K)
	continue;

	/* valid entries have a shift value */
	if (!mmu_psize_defs[size].shift)
	continue;

	if (penc == mmu_psize_defs[size].penc)
	break;
	}
	}

	/* This works for all page sizes, and for 256M and 1T segments */
	shift = mmu_psize_defs[size].shift;
	avpn = (HPTE_V_AVPN_VAL(hpte_v) & ~mmu_psize_defs[size].avpnm) << 23;

	if (shift < 23) {
	unsigned long vpi, vsid, pteg;

	pteg = slot / HPTES_PER_GROUP;
	if (hpte_v & HPTE_V_SECONDARY)
	pteg = ~pteg;
	switch (hpte_v >> HPTE_V_SSIZE_SHIFT) {
	case MMU_SEGSIZE_256M:
	vpi = ((avpn >> 28) ^ pteg) & htab_hash_mask;
	break;
	case MMU_SEGSIZE_1T:
	vsid = avpn >> 40;
	vpi = (vsid ^ (vsid << 25) ^ pteg) & htab_hash_mask;
	break;
	default:
	avpn = vpi = size = 0;
	}
	avpn \|= (vpi << mmu_psize_defs[size].shift);
	}

	*va = avpn;
	*psize = size;
	}

	/*
	* 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...
	*/
	static void native_hpte_clear(void)
	{
	unsigned long slot, slots, flags;
	struct hash_pte *hptep = htab_address;
	unsigned long hpte_v, va;
	unsigned long pteg_count;
	int psize;

	pteg_count = htab_hash_mask + 1;

	local_irq_save(flags);

	/* we take the tlbie lock and hold it. Some hardware will
	* deadlock if we try to tlbie from two processors at once.
	*/
	spin_lock(&native_tlbie_lock);

	slots = pteg_count * HPTES_PER_GROUP;

	for (slot = 0; slot < slots; slot++, hptep++) {
	/*
	* we could lock the pte here, but we are the only cpu
	* running, right? and for crash dump, we probably
	* don't want to wait for a maybe bad cpu.
	*/
	hpte_v = hptep->v;

	/*
	* Call __tlbie() here rather than tlbie() since we
	* already hold the native_tlbie_lock.
	*/
	if (hpte_v & HPTE_V_VALID) {
	hpte_decode(hptep, slot, &psize, &va);
	hptep->v = 0;
	__tlbie(va, psize);
	}
	}

	asm volatile("eieio; tlbsync; ptesync":::"memory");
	spin_unlock(&native_tlbie_lock);
	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, hash, index, hidx, shift, slot;
	struct hash_pte *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 psize = batch->psize;
	int i;

	local_irq_save(flags);

	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);
	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) &&
	mmu_psize_defs[psize].tlbiel && local) {
	asm volatile("ptesync":::"memory");
	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);

	if (lock_tlbie)
	spin_lock(&native_tlbie_lock);

	asm volatile("ptesync":::"memory");
	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)
	spin_unlock(&native_tlbie_lock);
	}

	local_irq_restore(flags);
	}

	#ifdef CONFIG_PPC_PSERIES
	/* Disable TLB batching on nighthawk */
	static inline int tlb_batching_enabled(void)
	{
	struct device_node *root = of_find_node_by_path("/");
	int enabled = 1;

	if (root) {
	const char *model = of_get_property(root, "model", NULL);
	if (model && !strcmp(model, "IBM,9076-N81"))
	enabled = 0;
	of_node_put(root);
	}

	return enabled;
	}
	#else
	static inline int tlb_batching_enabled(void)
	{
	return 1;
	}
	#endif

	void __init hpte_init_native(void)
	{
	ppc_md.hpte_invalidate = native_hpte_invalidate;
	ppc_md.hpte_updatepp = native_hpte_updatepp;
	ppc_md.hpte_updateboltedpp = native_hpte_updateboltedpp;
	ppc_md.hpte_insert = native_hpte_insert;
	ppc_md.hpte_remove = native_hpte_remove;
	ppc_md.hpte_clear_all = native_hpte_clear;
	if (tlb_batching_enabled())
	ppc_md.flush_hash_range = native_flush_hash_range;
	}