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-rw-r--r--arch/powerpc/mm/hugepage-hash64.c185
1 files changed, 185 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
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index 000000000..01f213d2b
--- /dev/null
+++ b/arch/powerpc/mm/hugepage-hash64.c
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+/*
+ * Copyright IBM Corporation, 2013
+ * 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 2.1 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.
+ *
+ */
+
+/*
+ * PPC64 THP Support for hash based MMUs
+ */
+#include <linux/mm.h>
+#include <asm/machdep.h>
+
+int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
+ pmd_t *pmdp, unsigned long trap, unsigned long flags,
+ int ssize, unsigned int psize)
+{
+ unsigned int index, valid;
+ unsigned char *hpte_slot_array;
+ unsigned long rflags, pa, hidx;
+ unsigned long old_pmd, new_pmd;
+ int ret, lpsize = MMU_PAGE_16M;
+ unsigned long vpn, hash, shift, slot;
+
+ /*
+ * atomically mark the linux large page PMD busy and dirty
+ */
+ do {
+ pmd_t pmd = READ_ONCE(*pmdp);
+
+ old_pmd = pmd_val(pmd);
+ /* If PMD busy, retry the access */
+ if (unlikely(old_pmd & H_PAGE_BUSY))
+ return 0;
+ /* If PMD permissions don't match, take page fault */
+ if (unlikely(!check_pte_access(access, old_pmd)))
+ return 1;
+ /*
+ * Try to lock the PTE, add ACCESSED and DIRTY if it was
+ * a write access
+ */
+ new_pmd = old_pmd | H_PAGE_BUSY | _PAGE_ACCESSED;
+ if (access & _PAGE_WRITE)
+ new_pmd |= _PAGE_DIRTY;
+ } while (!pmd_xchg(pmdp, __pmd(old_pmd), __pmd(new_pmd)));
+
+ rflags = htab_convert_pte_flags(new_pmd);
+
+#if 0
+ if (!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);
+ }
+#endif
+ /*
+ * Find the slot index details for this ea, using base page size.
+ */
+ shift = mmu_psize_defs[psize].shift;
+ index = (ea & ~HPAGE_PMD_MASK) >> shift;
+ BUG_ON(index >= PTE_FRAG_SIZE);
+
+ vpn = hpt_vpn(ea, vsid, ssize);
+ hpte_slot_array = get_hpte_slot_array(pmdp);
+ if (psize == MMU_PAGE_4K) {
+ /*
+ * invalidate the old hpte entry if we have that mapped via 64K
+ * base page size. This is because demote_segment won't flush
+ * hash page table entries.
+ */
+ if ((old_pmd & H_PAGE_HASHPTE) && !(old_pmd & H_PAGE_COMBO)) {
+ flush_hash_hugepage(vsid, ea, pmdp, MMU_PAGE_64K,
+ ssize, flags);
+ /*
+ * With THP, we also clear the slot information with
+ * respect to all the 64K hash pte mapping the 16MB
+ * page. They are all invalid now. This make sure we
+ * don't find the slot valid when we fault with 4k
+ * base page size.
+ *
+ */
+ memset(hpte_slot_array, 0, PTE_FRAG_SIZE);
+ }
+ }
+
+ valid = hpte_valid(hpte_slot_array, index);
+ if (valid) {
+ /* update the hpte bits */
+ hash = hpt_hash(vpn, shift, ssize);
+ hidx = hpte_hash_index(hpte_slot_array, index);
+ if (hidx & _PTEIDX_SECONDARY)
+ hash = ~hash;
+ slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+ slot += hidx & _PTEIDX_GROUP_IX;
+
+ ret = mmu_hash_ops.hpte_updatepp(slot, rflags, vpn,
+ psize, lpsize, ssize, flags);
+ /*
+ * We failed to update, try to insert a new entry.
+ */
+ if (ret == -1) {
+ /*
+ * large pte is marked busy, so we can be sure
+ * nobody is looking at hpte_slot_array. hence we can
+ * safely update this here.
+ */
+ valid = 0;
+ hpte_slot_array[index] = 0;
+ }
+ }
+
+ if (!valid) {
+ unsigned long hpte_group;
+
+ hash = hpt_hash(vpn, shift, ssize);
+ /* insert new entry */
+ pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT;
+ new_pmd |= H_PAGE_HASHPTE;
+
+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,
+ psize, lpsize, 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,
+ psize, lpsize, ssize);
+ if (slot == -1) {
+ if (mftb() & 0x1)
+ hpte_group = (hash & htab_hash_mask) *
+ HPTES_PER_GROUP;
+
+ mmu_hash_ops.hpte_remove(hpte_group);
+ goto repeat;
+ }
+ }
+ /*
+ * Hypervisor failure. Restore old pmd and return -1
+ * similar to __hash_page_*
+ */
+ if (unlikely(slot == -2)) {
+ *pmdp = __pmd(old_pmd);
+ hash_failure_debug(ea, access, vsid, trap, ssize,
+ psize, lpsize, old_pmd);
+ return -1;
+ }
+ /*
+ * large pte is marked busy, so we can be sure
+ * nobody is looking at hpte_slot_array. hence we can
+ * safely update this here.
+ */
+ mark_hpte_slot_valid(hpte_slot_array, index, slot);
+ }
+ /*
+ * Mark the pte with H_PAGE_COMBO, if we are trying to hash it with
+ * base page size 4k.
+ */
+ if (psize == MMU_PAGE_4K)
+ new_pmd |= H_PAGE_COMBO;
+ /*
+ * The hpte valid is stored in the pgtable whose address is in the
+ * second half of the PMD. Order this against clearing of the busy bit in
+ * huge pmd.
+ */
+ smp_wmb();
+ *pmdp = __pmd(new_pmd & ~H_PAGE_BUSY);
+ return 0;
+}