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124 lines
3.6 KiB
124 lines
3.6 KiB
/* |
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* Copyright IBM Corporation, 2015 |
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* Author Aneesh Kumar K.V <[email protected]> |
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* |
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* This program is free software; you can redistribute it and/or modify it |
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* under the terms of version 2 of the GNU Lesser General Public License |
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* as published by the Free Software Foundation. |
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* |
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* This program is distributed in the hope that it would be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
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* |
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*/ |
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#include <linux/mm.h> |
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#include <asm/machdep.h> |
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#include <asm/mmu.h> |
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int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, |
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pte_t *ptep, unsigned long trap, unsigned long flags, |
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int ssize, int subpg_prot) |
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{ |
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real_pte_t rpte; |
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unsigned long hpte_group; |
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unsigned long rflags, pa; |
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unsigned long old_pte, new_pte; |
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unsigned long vpn, hash, slot; |
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unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift; |
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/* |
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* atomically mark the linux large page PTE busy and dirty |
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*/ |
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do { |
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pte_t pte = READ_ONCE(*ptep); |
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old_pte = pte_val(pte); |
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/* If PTE busy, retry the access */ |
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if (unlikely(old_pte & H_PAGE_BUSY)) |
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return 0; |
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/* If PTE permissions don't match, take page fault */ |
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if (unlikely(!check_pte_access(access, old_pte))) |
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return 1; |
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/* |
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* Try to lock the PTE, add ACCESSED and DIRTY if it was |
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* a write access. Since this is 4K insert of 64K page size |
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* also add H_PAGE_COMBO |
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*/ |
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new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED; |
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if (access & _PAGE_WRITE) |
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new_pte |= _PAGE_DIRTY; |
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} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); |
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/* |
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* PP bits. _PAGE_USER is already PP bit 0x2, so we only |
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* need to add in 0x1 if it's a read-only user page |
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*/ |
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rflags = htab_convert_pte_flags(new_pte, flags); |
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rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE); |
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if (cpu_has_feature(CPU_FTR_NOEXECUTE) && |
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!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) |
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rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); |
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vpn = hpt_vpn(ea, vsid, ssize); |
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if (unlikely(old_pte & H_PAGE_HASHPTE)) { |
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/* |
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* There MIGHT be an HPTE for this pte |
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*/ |
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unsigned long gslot = pte_get_hash_gslot(vpn, shift, ssize, |
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rpte, 0); |
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if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_4K, |
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MMU_PAGE_4K, ssize, flags) == -1) |
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old_pte &= ~_PAGE_HPTEFLAGS; |
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} |
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if (likely(!(old_pte & H_PAGE_HASHPTE))) { |
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pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT; |
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hash = hpt_hash(vpn, shift, ssize); |
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repeat: |
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hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP; |
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/* Insert into the hash table, primary slot */ |
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slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0, |
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MMU_PAGE_4K, MMU_PAGE_4K, ssize); |
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/* |
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* Primary is full, try the secondary |
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*/ |
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if (unlikely(slot == -1)) { |
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hpte_group = (~hash & htab_hash_mask) * HPTES_PER_GROUP; |
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slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, |
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rflags, |
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HPTE_V_SECONDARY, |
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MMU_PAGE_4K, |
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MMU_PAGE_4K, ssize); |
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if (slot == -1) { |
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if (mftb() & 0x1) |
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hpte_group = (hash & htab_hash_mask) * |
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HPTES_PER_GROUP; |
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mmu_hash_ops.hpte_remove(hpte_group); |
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/* |
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* FIXME!! Should be try the group from which we removed ? |
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*/ |
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goto repeat; |
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} |
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} |
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/* |
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* Hypervisor failure. Restore old pte and return -1 |
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* similar to __hash_page_* |
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*/ |
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if (unlikely(slot == -2)) { |
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*ptep = __pte(old_pte); |
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hash_failure_debug(ea, access, vsid, trap, ssize, |
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MMU_PAGE_4K, MMU_PAGE_4K, old_pte); |
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return -1; |
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} |
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new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; |
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new_pte |= pte_set_hidx(ptep, rpte, 0, slot, PTRS_PER_PTE); |
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} |
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*ptep = __pte(new_pte & ~H_PAGE_BUSY); |
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return 0; |
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}
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