| /* |
| * Copyright IBM Corporation, 2015 |
| * 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 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; |
| } |