diff options
Diffstat (limited to 'arch/powerpc/mm/hash64_4k.c')
| -rw-r--r-- | arch/powerpc/mm/hash64_4k.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hash64_4k.c b/arch/powerpc/mm/hash64_4k.c new file mode 100644 index 000000000000..47d1b26effc6 --- /dev/null +++ b/arch/powerpc/mm/hash64_4k.c @@ -0,0 +1,123 @@ +/* + * 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) +{ + 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 & _PAGE_BUSY)) + return 0; + /* If PTE permissions don't match, take page fault */ + if (unlikely(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 _PAGE_COMBO + */ + new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED; + if (access & _PAGE_RW) + new_pte |= _PAGE_DIRTY; + } while (old_pte != __cmpxchg_u64((unsigned long *)ptep, + old_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); + + 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 & _PAGE_HASHPTE)) { + /* + * There MIGHT be an HPTE for this pte + */ + hash = hpt_hash(vpn, shift, ssize); + if (old_pte & _PAGE_F_SECOND) + hash = ~hash; + slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; + slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT; + + if (ppc_md.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_4K, + MMU_PAGE_4K, ssize, flags) == -1) + old_pte &= ~_PAGE_HPTEFLAGS; + } + + if (likely(!(old_pte & _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 = ppc_md.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 = ppc_md.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; + ppc_md.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) | _PAGE_HASHPTE; + new_pte |= (slot << _PAGE_F_GIX_SHIFT) & (_PAGE_F_SECOND | _PAGE_F_GIX); + } + *ptep = __pte(new_pte & ~_PAGE_BUSY); + return 0; +} |