1 files changed, 124 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_4k.c b/arch/powerpc/mm/book3s64/hash_4k.c
new file mode 100644
index 000000000..7de1a8a0c
--- /dev/null
+++ b/arch/powerpc/mm/book3s64/hash_4k.c
@@ -0,0 +1,124 @@
+/*
+ * 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>
+
+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 long rflags, pa;
+	unsigned long old_pte, new_pte;
+	unsigned long vpn, hash, slot;
+	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;
+		if (access & _PAGE_WRITE)
+			new_pte |= _PAGE_DIRTY;
+	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
+
+	/*
+	 * PP bits. _PAGE_USER is already PP bit 0x2, so we only
+	 * need to add in 0x1 if it's a read-only user page
+	 */
+	rflags = htab_convert_pte_flags(new_pte, flags);
+	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)) {
+		/*
+		 * There MIGHT be an HPTE for this pte
+		 */
+		unsigned long gslot = pte_get_hash_gslot(vpn, shift, ssize,
+							 rpte, 0);
+
+		if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_4K,
+					       MMU_PAGE_4K, 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_4K, MMU_PAGE_4K, 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_4K,
+							MMU_PAGE_4K, 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_4K, MMU_PAGE_4K, 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;
+}