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https://github.com/torvalds/linux
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75646c480f
Make sure we are operating on THP and hugetlb entries in the respective hash fault handling routines. No functional change in this patch. If we walked the table wrongly before, we will retry the access. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
124 lines
3.6 KiB
C
124 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later)
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*
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* Copyright (C) 2003 David Gibson, IBM Corporation.
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*
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* Based on the IA-32 version:
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* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/machdep.h>
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extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
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unsigned long pa, unsigned long rlags,
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unsigned long vflags, int psize, int ssize);
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int __hash_page_huge(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, unsigned int shift, unsigned int mmu_psize)
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{
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real_pte_t rpte;
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unsigned long vpn;
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unsigned long old_pte, new_pte;
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unsigned long rflags, pa, sz;
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long slot, offset;
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BUG_ON(shift != mmu_psize_defs[mmu_psize].shift);
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/* Search the Linux page table for a match with va */
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vpn = hpt_vpn(ea, vsid, ssize);
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/* At this point, we have a pte (old_pte) which can be used to build
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* or update an HPTE. There are 2 cases:
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*
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* 1. There is a valid (present) pte with no associated HPTE (this is
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* the most common case)
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* 2. There is a valid (present) pte with an associated HPTE. The
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* current values of the pp bits in the HPTE prevent access
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* because we are doing software DIRTY bit management and the
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* page is currently not DIRTY.
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*/
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do {
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old_pte = pte_val(*ptep);
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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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/* Try to lock the PTE, add ACCESSED and DIRTY if it was
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* a write access */
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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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/* Make sure this is a hugetlb entry */
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if (old_pte & (H_PAGE_THP_HUGE | _PAGE_DEVMAP))
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return 0;
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rflags = htab_convert_pte_flags(new_pte);
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if (unlikely(mmu_psize == MMU_PAGE_16G))
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offset = PTRS_PER_PUD;
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else
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offset = PTRS_PER_PMD;
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rpte = __real_pte(__pte(old_pte), ptep, offset);
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sz = ((1UL) << shift);
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if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
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/* No CPU has hugepages but lacks no execute, so we
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* don't need to worry about that case */
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rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
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/* Check if pte already has an hpte (case 2) */
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if (unlikely(old_pte & H_PAGE_HASHPTE)) {
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/* There MIGHT be an HPTE for this pte */
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unsigned long gslot;
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gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0);
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if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize,
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mmu_psize, 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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unsigned long hash = hpt_hash(vpn, shift, ssize);
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pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
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/* clear HPTE slot informations in new PTE */
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new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE;
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slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0,
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mmu_psize, ssize);
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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_psize, mmu_psize, old_pte);
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return -1;
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}
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new_pte |= pte_set_hidx(ptep, rpte, 0, slot, offset);
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}
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/*
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* No need to use ldarx/stdcx here
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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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