powerpc/mm: Convert 4k insert from asm to C

This is similar to 64K insert. May be we want to consolidate

Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/Makefile

@@ -14,11 +14,11 @@ obj-$(CONFIG_PPC_MMU_NOHASH)	+= mmu_context_nohash.o tlb_nohash.o \
 obj-$(CONFIG_PPC_BOOK3E)	+= tlb_low_$(CONFIG_WORD_SIZE)e.o
 hash64-$(CONFIG_PPC_NATIVE)	:= hash_native_64.o
 obj-$(CONFIG_PPC_STD_MMU_64)	+= hash_utils_64.o slb_low.o slb.o $(hash64-y)
-obj-$(CONFIG_PPC_STD_MMU_32)	+= ppc_mmu_32.o
-obj-$(CONFIG_PPC_STD_MMU)	+= hash_low_$(CONFIG_WORD_SIZE).o \
-				   tlb_hash$(CONFIG_WORD_SIZE).o \
+obj-$(CONFIG_PPC_STD_MMU_32)	+= ppc_mmu_32.o hash_low_32.o
+obj-$(CONFIG_PPC_STD_MMU)	+= tlb_hash$(CONFIG_WORD_SIZE).o \
 				   mmu_context_hash$(CONFIG_WORD_SIZE).o
 ifeq ($(CONFIG_PPC_STD_MMU_64),y)
+obj-$(CONFIG_PPC_4K_PAGES)	+= hash64_4k.o
 obj-$(CONFIG_PPC_64K_PAGES)	+= hash64_64k.o
 endif
 obj-$(CONFIG_PPC_ICSWX)		+= icswx.o

arch/powerpc/mm/hash64_4k.c

@@ -0,0 +1,139 @@
+/*
+ * Copyright IBM Corporation, 2015
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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)
+{
+	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 & _PAGE_BUSY))
+			return 0;
+		/* If PTE permissions don't match, take page fault */
+		if (unlikely(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 _PAGE_COMBO
+		 */
+		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE;
+		if (access & _PAGE_RW)
+			new_pte |= _PAGE_DIRTY;
+	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
+					  old_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 = new_pte & _PAGE_USER;
+	if ((new_pte & _PAGE_USER) && !((new_pte & _PAGE_RW) &&
+					(new_pte & _PAGE_DIRTY)))
+		rflags |= 0x1;
+	/*
+	 * _PAGE_EXEC -> HW_NO_EXEC since it's inverted
+	 */
+	rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
+	/*
+	 * Always add C and Memory coherence bit
+	 */
+	rflags |= HPTE_R_C | HPTE_R_M;
+	/*
+	 * Add in WIMG bits
+	 */
+	rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+				_PAGE_COHERENT | _PAGE_GUARDED));
+
+	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 & _PAGE_HASHPTE)) {
+		/*
+		 * There MIGHT be an HPTE for this pte
+		 */
+		hash = hpt_hash(vpn, shift, ssize);
+		if (old_pte & _PAGE_F_SECOND)
+			hash = ~hash;
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT;
+
+		if (ppc_md.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_4K,
+					 MMU_PAGE_4K, ssize, flags) == -1)
+			old_pte &= ~_PAGE_HPTEFLAGS;
+	}
+
+	if (likely(!(old_pte & _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) & ~0x7UL;
+
+		/* Insert into the hash table, primary slot */
+		slot = ppc_md.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) & ~0x7UL;
+			slot = ppc_md.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) & ~0x7UL;
+				ppc_md.hpte_remove(hpte_group);
+				/*
+				 * FIXME!! Should be try the group from which we removed ?
+				 */
+				goto repeat;
+			}
+		}
+		/*
+		 * Hypervisor failure. Restore old pmd 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) | _PAGE_HASHPTE;
+		new_pte |= (slot << _PAGE_F_GIX_SHIFT) & (_PAGE_F_SECOND | _PAGE_F_GIX);
+	}
+	*ptep = __pte(new_pte & ~_PAGE_BUSY);
+	return 0;
+}