/* * Copyright IBM Corporation, 2015 * Author Aneesh Kumar K.V * * 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 #include #include /* * 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; }