From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755338Ab0HDSbk (ORCPT ); Wed, 4 Aug 2010 14:31:40 -0400 Received: from claw.goop.org ([74.207.240.146]:59398 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754029Ab0HDSbj (ORCPT ); Wed, 4 Aug 2010 14:31:39 -0400 Message-ID: <4C59B205.5020505@goop.org> Date: Wed, 04 Aug 2010 11:31:33 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.1 MIME-Version: 1.0 To: "H. Peter Anvin" CC: the arch/x86 maintainers , Linux Kernel Mailing List , Dave McCracken , Thomas Gleixner , Ingo Molnar Subject: Re: [PATCH] x86/hugetlb: use set_pmd for huge pte operations References: <4C4DE5BF.1030603@goop.org> In-Reply-To: <4C4DE5BF.1030603@goop.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2010 12:45 PM, Jeremy Fitzhardinge wrote: Ping? I was about to send this to Linus, but I realized that I hadn't got any x86 acks on it. Any comments/complaints? Thanks, J > > On x86, a huge pte is logically a pte, but structurally a pmd. Among > other issues, pmds and ptes overload some flags for multiple uses (PAT > vs PSE), so it is necessary to know which structural level a pagetable > entry is in order interpret it properly. > > When huge pages are used within a paravirtualized system, it is therefore > appropriate to use the pmd set of function to operate on them, so that > the hypervisor can correctly validate the update. > > [ Add fix for 32-bit non-PAE with two-level pagetable - Jeremy ] > > Signed-off-by: Dave McCracken > Signed-off-by: Jeremy Fitzhardinge > > diff --git a/arch/x86/include/asm/hugetlb.h > b/arch/x86/include/asm/hugetlb.h > index 439a9ac..bf88684 100644 > --- a/arch/x86/include/asm/hugetlb.h > +++ b/arch/x86/include/asm/hugetlb.h > @@ -36,16 +36,28 @@ static inline void hugetlb_free_pgd_range(struct > mmu_gather *tlb, > free_pgd_range(tlb, addr, end, floor, ceiling); > } > > +static inline pte_t huge_ptep_get(pte_t *ptep) > +{ > + return *ptep; > +} > + > static inline void set_huge_pte_at(struct mm_struct *mm, unsigned > long addr, > pte_t *ptep, pte_t pte) > { > - set_pte_at(mm, addr, ptep, pte); > +#if PAGETABLE_LEVELS>= 3 > + set_pmd((pmd_t *)ptep, native_make_pmd(native_pte_val(pte))); > +#else > + set_pgd((pgd_t *)ptep, native_make_pgd(native_pte_val(pte))); > +#endif > } > > static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, > unsigned long addr, pte_t *ptep) > { > - return ptep_get_and_clear(mm, addr, ptep); > + pte_t pte = huge_ptep_get(ptep); > + > + set_huge_pte_at(mm, addr, ptep, __pte(0)); > + return pte; > } > > static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, > @@ -66,19 +78,25 @@ static inline pte_t huge_pte_wrprotect(pte_t pte) > static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, > unsigned long addr, pte_t *ptep) > { > - ptep_set_wrprotect(mm, addr, ptep); > + pte_t pte = huge_ptep_get(ptep); > + > + pte = pte_wrprotect(pte); > + set_huge_pte_at(mm, addr, ptep, pte); > } > > static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma, > unsigned long addr, pte_t *ptep, > pte_t pte, int dirty) > { > - return ptep_set_access_flags(vma, addr, ptep, pte, dirty); > -} > + pte_t oldpte = huge_ptep_get(ptep); > + int changed = !pte_same(oldpte, pte); > > -static inline pte_t huge_ptep_get(pte_t *ptep) > -{ > - return *ptep; > + if (changed&& dirty) { > + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); > + flush_tlb_page(vma, addr); > + } > + > + return changed; > } > > static inline int arch_prepare_hugepage(struct page *page) > > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >