/* * Copyright IBM Corporation, 2013 * 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 2.1 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))); /* * Make sure this is thp or devmap entry */ if (!(old_pmd & (H_PAGE_THP_HUGE | _PAGE_DEVMAP))) return 0; 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; }