Messages in this thread | | | Subject | Re: [PATCH 6/6] x86: Fix stray A/D bit setting into non-present PTEs | From | Nadav Amit <> | Date | Thu, 30 Jun 2016 18:50:21 -0700 |
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Dave Hansen <dave@sr71.net> wrote:
> +pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, > + pte_t *ptep) > +{ > + struct mm_struct *mm = vma->vm_mm; > + pte_t pte; > + > + pte = ptep_get_and_clear(mm, address, ptep); > + if (pte_accessible(mm, pte)) { > + flush_tlb_page(vma, address); > + /* > + * Ensure that the compiler orders our set_pte() > + * after the flush_tlb_page() no matter what. > + */ > + barrier();
I don’t think such a barrier (after remote TLB flush) is needed. Eventually, if a remote flush takes place, you get csd_lock_wait() to be called, and then smp_rmb() is called (which is essentially a barrier() call on x86).
Regards, Nadav
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