diff options
Diffstat (limited to 'kernel/arch/powerpc/mm/hugepage-hash64.c')
| -rw-r--r-- | kernel/arch/powerpc/mm/hugepage-hash64.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/mm/hugepage-hash64.c b/kernel/arch/powerpc/mm/hugepage-hash64.c new file mode 100644 index 000000000..43dafb9d6 --- /dev/null +++ b/kernel/arch/powerpc/mm/hugepage-hash64.c @@ -0,0 +1,195 @@ +/* + * Copyright IBM Corporation, 2013 + * 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 2.1 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 & _PAGE_BUSY)) + return 0; + /* If PMD is trans splitting retry the access */ + if (unlikely(old_pmd & _PAGE_SPLITTING)) + return 0; + /* If PMD permissions don't match, take page fault */ + if (unlikely(access & ~old_pmd)) + return 1; + /* + * Try to lock the PTE, add ACCESSED and DIRTY if it was + * a write access + */ + new_pmd = old_pmd | _PAGE_BUSY | _PAGE_ACCESSED; + if (access & _PAGE_RW) + new_pmd |= _PAGE_DIRTY; + } while (old_pmd != __cmpxchg_u64((unsigned long *)pmdp, + old_pmd, new_pmd)); + /* + * 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 = new_pmd & _PAGE_USER; + if ((new_pmd & _PAGE_USER) && !((new_pmd & _PAGE_RW) && + (new_pmd & _PAGE_DIRTY))) + rflags |= 0x1; + /* + * _PAGE_EXEC -> HW_NO_EXEC since it's inverted + */ + rflags |= ((new_pmd & _PAGE_EXEC) ? 0 : HPTE_R_N); + +#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 >= 4096); + + vpn = hpt_vpn(ea, vsid, ssize); + hash = hpt_hash(vpn, shift, 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 & _PAGE_HASHPTE) && !(old_pmd & _PAGE_COMBO)) + flush_hash_hugepage(vsid, ea, pmdp, MMU_PAGE_64K, + ssize, flags); + } + + valid = hpte_valid(hpte_slot_array, index); + if (valid) { + /* update the hpte bits */ + 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 = ppc_md.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; + + /* insert new entry */ + pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT; + new_pmd |= _PAGE_HASHPTE; + + /* Add in WIMG bits */ + rflags |= (new_pmd & (_PAGE_WRITETHRU | _PAGE_NO_CACHE | + _PAGE_GUARDED)); + /* + * enable the memory coherence always + */ + rflags |= HPTE_R_M; +repeat: + hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; + + /* Insert into the hash table, primary slot */ + slot = ppc_md.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) & ~0x7UL; + slot = ppc_md.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) & ~0x7UL; + + ppc_md.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 _PAGE_COMBO, if we are trying to hash it with + * base page size 4k. + */ + if (psize == MMU_PAGE_4K) + new_pmd |= _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 & ~_PAGE_BUSY); + return 0; +} |