/* * 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 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 & 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; if (access & _PAGE_WRITE) new_pte |= _PAGE_DIRTY; } while (!pte_xchg(ptep, __pte(old_pte), __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 = 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)) { /* * There MIGHT be an HPTE for this pte */ unsigned long gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0); if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_4K, MMU_PAGE_4K, 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_4K, MMU_PAGE_4K, 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_4K, MMU_PAGE_4K, 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_4K, MMU_PAGE_4K, 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; }