powerpc/mm: Convert 4k hash insert to C
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>
diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
new file mode 100644
index 0000000..9ffeae2
--- /dev/null
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -0,0 +1,202 @@
+/*
+ * 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)
+{
+ real_pte_t rpte;
+ unsigned long *hidxp;
+ unsigned long hpte_group;
+ unsigned int subpg_index;
+ unsigned long rflags, pa, hidx;
+ unsigned long old_pte, new_pte, subpg_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_COMBO;
+ if (access & _PAGE_RW)
+ new_pte |= _PAGE_DIRTY;
+ } while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
+ old_pte, new_pte));
+ /*
+ * Handle the subpage protection bits
+ */
+ subpg_pte = new_pte & ~subpg_prot;
+ /*
+ * 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 = subpg_pte & _PAGE_USER;
+ if ((subpg_pte & _PAGE_USER) && !((subpg_pte & _PAGE_RW) &&
+ (subpg_pte & _PAGE_DIRTY)))
+ rflags |= 0x1;
+ /*
+ * _PAGE_EXEC -> HW_NO_EXEC since it's inverted
+ */
+ rflags |= ((subpg_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 |= (subpg_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+ _PAGE_COHERENT | _PAGE_GUARDED));
+
+ 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);
+ /*
+ *None of the sub 4k page is hashed
+ */
+ if (!(old_pte & _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 & _PAGE_COMBO)) {
+ flush_hash_page(vpn, rpte, MMU_PAGE_64K, ssize, flags);
+ old_pte &= ~_PAGE_HPTE_SUB;
+ goto htab_insert_hpte;
+ }
+ /*
+ * Check for sub page valid and update
+ */
+ if (__rpte_sub_valid(rpte, subpg_index)) {
+ int ret;
+
+ hash = hpt_hash(vpn, shift, ssize);
+ hidx = __rpte_to_hidx(rpte, subpg_index);
+ if (hidx & _PTEIDX_SECONDARY)
+ hash = ~hash;
+ slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+ slot += hidx & _PTEIDX_GROUP_IX;
+
+ ret = ppc_md.hpte_updatepp(slot, 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 & ~_PAGE_BUSY);
+ return 0;
+ }
+
+htab_insert_hpte:
+ /*
+ * handle _PAGE_4K_PFN case
+ */
+ if (old_pte & _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) & ~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;
+ }
+ /*
+ * Insert slot number & secondary bit in PTE second half,
+ * clear _PAGE_BUSY and set appropriate HPTE slot bit
+ * Since we have _PAGE_BUSY set on ptep, we can be sure
+ * nobody is undating hidx.
+ */
+ hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
+ /* __real_pte use pte_val() any idea why ? FIXME!! */
+ rpte.hidx &= ~(0xfUL << (subpg_index << 2));
+ *hidxp = rpte.hidx | (slot << (subpg_index << 2));
+ new_pte |= (_PAGE_HPTE_SUB0 >> subpg_index);
+ /*
+ * check __real_pte for details on matching smp_rmb()
+ */
+ smp_wmb();
+ *ptep = __pte(new_pte & ~_PAGE_BUSY);
+ return 0;
+}