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-rw-r--r--arch/powerpc/mm/hash64_64k.c333
1 files changed, 333 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
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index 000000000..3afa253d7
--- /dev/null
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -0,0 +1,333 @@
+/*
+ * 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>
+
+/*
+ * 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;
+}
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