1 files changed, 333 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_64k.c b/arch/powerpc/mm/book3s64/hash_64k.c
new file mode 100644
index 000000000000..7084ce2951e6
--- /dev/null
+++ b/arch/powerpc/mm/book3s64/hash_64k.c
@@ -0,0 +1,333 @@
+/*
+ * Copyright IBM Corporation, 2015
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/mm.h>
+#include <asm/machdep.h>
+#include <asm/mmu.h>
+
+/*
+ * Return true, if the entry has a slot value which
+ * the software considers as invalid.
+ */
+static inline bool hpte_soft_invalid(unsigned long hidx)
+{
+	return ((hidx & 0xfUL) == 0xfUL);
+}
+
+/*
+ * index from 0 - 15
+ */
+bool __rpte_sub_valid(real_pte_t rpte, unsigned long index)
+{
+	return !(hpte_soft_invalid(__rpte_to_hidx(rpte, index)));
+}
+
+int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
+		   pte_t *ptep, unsigned long trap, unsigned long flags,
+		   int ssize, int subpg_prot)
+{
+	real_pte_t rpte;
+	unsigned long hpte_group;
+	unsigned int subpg_index;
+	unsigned long rflags, pa;
+	unsigned long old_pte, new_pte, subpg_pte;
+	unsigned long vpn, hash, slot, gslot;
+	unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift;
+
+	/*
+	 * atomically mark the linux large page PTE busy and dirty
+	 */
+	do {
+		pte_t pte = READ_ONCE(*ptep);
+
+		old_pte = pte_val(pte);
+		/* If PTE busy, retry the access */
+		if (unlikely(old_pte & H_PAGE_BUSY))
+			return 0;
+		/* If PTE permissions don't match, take page fault */
+		if (unlikely(!check_pte_access(access, old_pte)))
+			return 1;
+		/*
+		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
+		 * a write access. Since this is 4K insert of 64K page size
+		 * also add H_PAGE_COMBO
+		 */
+		new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED | H_PAGE_COMBO;
+		if (access & _PAGE_WRITE)
+			new_pte |= _PAGE_DIRTY;
+	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
+
+	/*
+	 * Handle the subpage protection bits
+	 */
+	subpg_pte = new_pte & ~subpg_prot;
+	rflags = htab_convert_pte_flags(subpg_pte);
+
+	if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+
+		/*
+		 * No CPU has hugepages but lacks no execute, so we
+		 * don't need to worry about that case
+		 */
+		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
+	}
+
+	subpg_index = (ea & (PAGE_SIZE - 1)) >> shift;
+	vpn  = hpt_vpn(ea, vsid, ssize);
+	rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE);
+	/*
+	 *None of the sub 4k page is hashed
+	 */
+	if (!(old_pte & H_PAGE_HASHPTE))
+		goto htab_insert_hpte;
+	/*
+	 * Check if the pte was already inserted into the hash table
+	 * as a 64k HW page, and invalidate the 64k HPTE if so.
+	 */
+	if (!(old_pte & H_PAGE_COMBO)) {
+		flush_hash_page(vpn, rpte, MMU_PAGE_64K, ssize, flags);
+		/*
+		 * clear the old slot details from the old and new pte.
+		 * On hash insert failure we use old pte value and we don't
+		 * want slot information there if we have a insert failure.
+		 */
+		old_pte &= ~H_PAGE_HASHPTE;
+		new_pte &= ~H_PAGE_HASHPTE;
+		goto htab_insert_hpte;
+	}
+	/*
+	 * Check for sub page valid and update
+	 */
+	if (__rpte_sub_valid(rpte, subpg_index)) {
+		int ret;
+
+		gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte,
+					   subpg_index);
+		ret = mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn,
+						 MMU_PAGE_4K, MMU_PAGE_4K,
+						 ssize, flags);
+
+		/*
+		 * If we failed because typically the HPTE wasn't really here
+		 * we try an insertion.
+		 */
+		if (ret == -1)
+			goto htab_insert_hpte;
+
+		*ptep = __pte(new_pte & ~H_PAGE_BUSY);
+		return 0;
+	}
+
+htab_insert_hpte:
+
+	/*
+	 * Initialize all hidx entries to invalid value, the first time
+	 * the PTE is about to allocate a 4K HPTE.
+	 */
+	if (!(old_pte & H_PAGE_COMBO))
+		rpte.hidx = INVALID_RPTE_HIDX;
+
+	/*
+	 * handle H_PAGE_4K_PFN case
+	 */
+	if (old_pte & H_PAGE_4K_PFN) {
+		/*
+		 * All the sub 4k page have the same
+		 * physical address.
+		 */
+		pa = pte_pfn(__pte(old_pte)) << HW_PAGE_SHIFT;
+	} else {
+		pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+		pa += (subpg_index << shift);
+	}
+	hash = hpt_hash(vpn, shift, ssize);
+repeat:
+	hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+
+	/* Insert into the hash table, primary slot */
+	slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0,
+					MMU_PAGE_4K, MMU_PAGE_4K, ssize);
+	/*
+	 * Primary is full, try the secondary
+	 */
+	if (unlikely(slot == -1)) {
+		bool soft_invalid;
+
+		hpte_group = (~hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa,
+						rflags, HPTE_V_SECONDARY,
+						MMU_PAGE_4K, MMU_PAGE_4K,
+						ssize);
+
+		soft_invalid = hpte_soft_invalid(slot);
+		if (unlikely(soft_invalid)) {
+			/*
+			 * We got a valid slot from a hardware point of view.
+			 * but we cannot use it, because we use this special
+			 * value; as defined by hpte_soft_invalid(), to track
+			 * invalid slots. We cannot use it. So invalidate it.
+			 */
+			gslot = slot & _PTEIDX_GROUP_IX;
+			mmu_hash_ops.hpte_invalidate(hpte_group + gslot, vpn,
+						     MMU_PAGE_4K, MMU_PAGE_4K,
+						     ssize, 0);
+		}
+
+		if (unlikely(slot == -1 || soft_invalid)) {
+			/*
+			 * For soft invalid slot, let's ensure that we release a
+			 * slot from the primary, with the hope that we will
+			 * acquire that slot next time we try. This will ensure
+			 * that we do not get the same soft-invalid slot.
+			 */
+			if (soft_invalid || (mftb() & 0x1))
+				hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+
+			mmu_hash_ops.hpte_remove(hpte_group);
+			/*
+			 * FIXME!! Should be try the group from which we removed ?
+			 */
+			goto repeat;
+		}
+	}
+	/*
+	 * Hypervisor failure. Restore old pte and return -1
+	 * similar to __hash_page_*
+	 */
+	if (unlikely(slot == -2)) {
+		*ptep = __pte(old_pte);
+		hash_failure_debug(ea, access, vsid, trap, ssize,
+				   MMU_PAGE_4K, MMU_PAGE_4K, old_pte);
+		return -1;
+	}
+
+	new_pte |= pte_set_hidx(ptep, rpte, subpg_index, slot, PTRS_PER_PTE);
+	new_pte |= H_PAGE_HASHPTE;
+
+	*ptep = __pte(new_pte & ~H_PAGE_BUSY);
+	return 0;
+}
+
+int __hash_page_64K(unsigned long ea, unsigned long access,
+		    unsigned long vsid, pte_t *ptep, unsigned long trap,
+		    unsigned long flags, int ssize)
+{
+	real_pte_t rpte;
+	unsigned long hpte_group;
+	unsigned long rflags, pa;
+	unsigned long old_pte, new_pte;
+	unsigned long vpn, hash, slot;
+	unsigned long shift = mmu_psize_defs[MMU_PAGE_64K].shift;
+
+	/*
+	 * atomically mark the linux large page PTE busy and dirty
+	 */
+	do {
+		pte_t pte = READ_ONCE(*ptep);
+
+		old_pte = pte_val(pte);
+		/* If PTE busy, retry the access */
+		if (unlikely(old_pte & H_PAGE_BUSY))
+			return 0;
+		/* If PTE permissions don't match, take page fault */
+		if (unlikely(!check_pte_access(access, old_pte)))
+			return 1;
+		/*
+		 * Check if PTE has the cache-inhibit bit set
+		 * If so, bail out and refault as a 4k page
+		 */
+		if (!mmu_has_feature(MMU_FTR_CI_LARGE_PAGE) &&
+		    unlikely(pte_ci(pte)))
+			return 0;
+		/*
+		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
+		 * a write access.
+		 */
+		new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED;
+		if (access & _PAGE_WRITE)
+			new_pte |= _PAGE_DIRTY;
+	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
+
+	rflags = htab_convert_pte_flags(new_pte);
+	rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE);
+
+	if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
+
+	vpn  = hpt_vpn(ea, vsid, ssize);
+	if (unlikely(old_pte & H_PAGE_HASHPTE)) {
+		unsigned long gslot;
+
+		/*
+		 * There MIGHT be an HPTE for this pte
+		 */
+		gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0);
+		if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_64K,
+					       MMU_PAGE_64K, ssize,
+					       flags) == -1)
+			old_pte &= ~_PAGE_HPTEFLAGS;
+	}
+
+	if (likely(!(old_pte & H_PAGE_HASHPTE))) {
+
+		pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+		hash = hpt_hash(vpn, shift, ssize);
+
+repeat:
+		hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+
+		/* Insert into the hash table, primary slot */
+		slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0,
+						MMU_PAGE_64K, MMU_PAGE_64K,
+						ssize);
+		/*
+		 * Primary is full, try the secondary
+		 */
+		if (unlikely(slot == -1)) {
+			hpte_group = (~hash & htab_hash_mask) * HPTES_PER_GROUP;
+			slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa,
+							rflags,
+							HPTE_V_SECONDARY,
+							MMU_PAGE_64K,
+							MMU_PAGE_64K, ssize);
+			if (slot == -1) {
+				if (mftb() & 0x1)
+					hpte_group = (hash & htab_hash_mask) *
+							HPTES_PER_GROUP;
+				mmu_hash_ops.hpte_remove(hpte_group);
+				/*
+				 * FIXME!! Should be try the group from which we removed ?
+				 */
+				goto repeat;
+			}
+		}
+		/*
+		 * Hypervisor failure. Restore old pte and return -1
+		 * similar to __hash_page_*
+		 */
+		if (unlikely(slot == -2)) {
+			*ptep = __pte(old_pte);
+			hash_failure_debug(ea, access, vsid, trap, ssize,
+					   MMU_PAGE_64K, MMU_PAGE_64K, old_pte);
+			return -1;
+		}
+
+		new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE;
+		new_pte |= pte_set_hidx(ptep, rpte, 0, slot, PTRS_PER_PTE);
+	}
+	*ptep = __pte(new_pte & ~H_PAGE_BUSY);
+	return 0;
+}