| /* |
| * 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> |
| /* |
| * index from 0 - 15 |
| */ |
| bool __rpte_sub_valid(real_pte_t rpte, unsigned long index) |
| { |
| unsigned long g_idx; |
| unsigned long ptev = pte_val(rpte.pte); |
| |
| g_idx = (ptev & H_PAGE_COMBO_VALID) >> H_PAGE_F_GIX_SHIFT; |
| index = index >> 2; |
| if (g_idx & (0x1 << index)) |
| return true; |
| else |
| return false; |
| } |
| /* |
| * index from 0 - 15 |
| */ |
| static unsigned long mark_subptegroup_valid(unsigned long ptev, unsigned long index) |
| { |
| unsigned long g_idx; |
| |
| if (!(ptev & H_PAGE_COMBO)) |
| return ptev; |
| index = index >> 2; |
| g_idx = 0x1 << index; |
| |
| return ptev | (g_idx << H_PAGE_F_GIX_SHIFT); |
| } |
| |
| 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 *hidxp; |
| unsigned long hpte_group; |
| unsigned int subpg_index; |
| unsigned long rflags, pa, hidx; |
| unsigned long old_pte, new_pte, subpg_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 | 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); |
| /* |
| *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 | H_PAGE_F_GIX | H_PAGE_F_SECOND); |
| new_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND); |
| goto htab_insert_hpte; |
| } |
| /* |
| * Check for sub page valid and update |
| */ |
| if (__rpte_sub_valid(rpte, subpg_index)) { |
| int ret; |
| |
| hash = hpt_hash(vpn, shift, ssize); |
| hidx = __rpte_to_hidx(rpte, subpg_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, |
| 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: |
| /* |
| * 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) & ~0x7UL; |
| |
| /* 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) & ~0x7UL; |
| 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) & ~0x7UL; |
| 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; |
| } |
| /* |
| * Insert slot number & secondary bit in PTE second half, |
| * clear H_PAGE_BUSY and set appropriate HPTE slot bit |
| * Since we have H_PAGE_BUSY set on ptep, we can be sure |
| * nobody is undating hidx. |
| */ |
| hidxp = (unsigned long *)(ptep + PTRS_PER_PTE); |
| rpte.hidx &= ~(0xfUL << (subpg_index << 2)); |
| *hidxp = rpte.hidx | (slot << (subpg_index << 2)); |
| new_pte = mark_subptegroup_valid(new_pte, subpg_index); |
| new_pte |= H_PAGE_HASHPTE; |
| /* |
| * check __real_pte for details on matching smp_rmb() |
| */ |
| smp_wmb(); |
| *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) |
| { |
| 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); |
| |
| 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 |
| */ |
| hash = hpt_hash(vpn, shift, ssize); |
| if (old_pte & H_PAGE_F_SECOND) |
| hash = ~hash; |
| slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; |
| slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; |
| |
| if (mmu_hash_ops.hpte_updatepp(slot, 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) & ~0x7UL; |
| |
| /* 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) & ~0x7UL; |
| 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) & ~0x7UL; |
| 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 |= (slot << H_PAGE_F_GIX_SHIFT) & |
| (H_PAGE_F_SECOND | H_PAGE_F_GIX); |
| } |
| *ptep = __pte(new_pte & ~H_PAGE_BUSY); |
| return 0; |
| } |