forked from luck/tmp_suning_uos_patched
powerpc/book3s64/hash: Use the pte_t address from the caller
Don't fetch the pte value using lockless page table walk. Instead use the value from the caller. hash_preload is called with ptl lock held. So it is safe to use the pte_t address directly. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200505071729.54912-6-aneesh.kumar@linux.ibm.com
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@ -1546,14 +1546,11 @@ static bool should_hash_preload(struct mm_struct *mm, unsigned long ea)
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}
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#endif
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static void hash_preload(struct mm_struct *mm, unsigned long ea,
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static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea,
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bool is_exec, unsigned long trap)
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{
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int hugepage_shift;
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unsigned long vsid;
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pgd_t *pgdir;
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pte_t *ptep;
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unsigned long flags;
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int rc, ssize, update_flags = 0;
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unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0);
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@ -1575,30 +1572,18 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea,
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vsid = get_user_vsid(&mm->context, ea, ssize);
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if (!vsid)
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return;
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/*
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* Hash doesn't like irqs. Walking linux page table with irq disabled
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* saves us from holding multiple locks.
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*/
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local_irq_save(flags);
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/*
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* THP pages use update_mmu_cache_pmd. We don't do
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* hash preload there. Hence can ignore THP here
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*/
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ptep = find_current_mm_pte(pgdir, ea, NULL, &hugepage_shift);
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if (!ptep)
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goto out_exit;
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WARN_ON(hugepage_shift);
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#ifdef CONFIG_PPC_64K_PAGES
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/* If either H_PAGE_4K_PFN or cache inhibited is set (and we are on
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* a 64K kernel), then we don't preload, hash_page() will take
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* care of it once we actually try to access the page.
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* That way we don't have to duplicate all of the logic for segment
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* page size demotion here
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* Called with PTL held, hence can be sure the value won't change in
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* between.
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*/
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if ((pte_val(*ptep) & H_PAGE_4K_PFN) || pte_ci(*ptep))
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goto out_exit;
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return;
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#endif /* CONFIG_PPC_64K_PAGES */
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/* Is that local to this CPU ? */
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@ -1623,8 +1608,6 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea,
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mm_ctx_user_psize(&mm->context),
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mm_ctx_user_psize(&mm->context),
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pte_val(*ptep));
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out_exit:
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local_irq_restore(flags);
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}
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/*
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@ -1675,7 +1658,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
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return;
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}
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hash_preload(vma->vm_mm, address, is_exec, trap);
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hash_preload(vma->vm_mm, ptep, address, is_exec, trap);
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}
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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