From patchwork Tue Jun 11 01:12:14 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 17754 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-gh0-f199.google.com (mail-gh0-f199.google.com [209.85.160.199]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id 0C95B25DFB for ; Tue, 11 Jun 2013 01:12:58 +0000 (UTC) Received: by mail-gh0-f199.google.com with SMTP id g14sf4333859ghb.2 for ; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:x-beenthere:x-forwarded-to:x-forwarded-for :delivered-to:from:to:cc:subject:date:message-id:x-mailer :in-reply-to:references:x-gm-message-state:x-original-sender :x-original-authentication-results:precedence:mailing-list:list-id :x-google-group-id:list-post:list-help:list-archive:list-unsubscribe; bh=apRm20ShvwcJ3/ZOjygS2wg+nYnXbgw2ONFhX4P7xY8=; b=M0b0WccTPV1SYdYXeI2+1uvTj/6iRToXcDvM4LESKIB8RLk3cWabR9Do5DwzANZILn 5tGvuB7znoOuyP87RPpzZmId3FIn90uuIjcW02KU5iQII30otNZdWHR/+xcwYevBgI5e ra280/wcLqCWt0P5xPyNLcF6qZ9IVQuovRYGIKvzdOPQMfQqVP8Vp+GQlnOn7AkGZlXz uPmmcolu8yp/hPziSvrW7bd9yqQVS3crQqlp33rV570hvS6qiKi+SkqpvZGlOJ17dRaP IXt7BWFBG6KQEvtNzkvNW3TmK9CFkxwIN1Z1a6Eo/yxyXg5mCx1ttrADTfWrra2GS/iK KVMQ== X-Received: by 10.224.53.198 with SMTP id n6mr9769063qag.2.1370913177667; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) MIME-Version: 1.0 X-BeenThere: patchwork-forward@linaro.org Received: by 10.49.122.5 with SMTP id lo5ls2930432qeb.27.gmail; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) X-Received: by 10.52.18.137 with SMTP id w9mr6088449vdd.50.1370913177469; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) Received: from mail-ve0-x22c.google.com (mail-ve0-x22c.google.com [2607:f8b0:400c:c01::22c]) by mx.google.com with ESMTPS id sc6si6144721vdc.86.2013.06.10.18.12.57 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 10 Jun 2013 18:12:57 -0700 (PDT) Received-SPF: neutral (google.com: 2607:f8b0:400c:c01::22c is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) client-ip=2607:f8b0:400c:c01::22c; Received: by mail-ve0-f172.google.com with SMTP id jz10so5327551veb.17 for ; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) X-Received: by 10.220.170.72 with SMTP id c8mr7261453vcz.14.1370913177307; Mon, 10 Jun 2013 18:12:57 -0700 (PDT) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patches@linaro.org Received: by 10.221.10.206 with SMTP id pb14csp89606vcb; Mon, 10 Jun 2013 18:12:56 -0700 (PDT) X-Received: by 10.66.37.43 with SMTP id v11mr16148037paj.108.1370913175978; Mon, 10 Jun 2013 18:12:55 -0700 (PDT) Received: from mail-pa0-x231.google.com (mail-pa0-x231.google.com [2607:f8b0:400e:c03::231]) by mx.google.com with ESMTPS id tr9si5805704pbc.283.2013.06.10.18.12.55 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 10 Jun 2013 18:12:55 -0700 (PDT) Received-SPF: neutral (google.com: 2607:f8b0:400e:c03::231 is neither permitted nor denied by best guess record for domain of john.stultz@linaro.org) client-ip=2607:f8b0:400e:c03::231; Received: by mail-pa0-f49.google.com with SMTP id ld11so2077380pab.8 for ; Mon, 10 Jun 2013 18:12:55 -0700 (PDT) X-Received: by 10.67.5.168 with SMTP id cn8mr16574282pad.119.1370913175584; Mon, 10 Jun 2013 18:12:55 -0700 (PDT) Received: from localhost.localdomain (c-67-170-153-23.hsd1.or.comcast.net. [67.170.153.23]) by mx.google.com with ESMTPSA id qe10sm9802489pbb.2.2013.06.10.18.12.54 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 10 Jun 2013 18:12:55 -0700 (PDT) From: John Stultz To: minchan@kernel.org Cc: dgiani@mozilla.com, John Stultz Subject: [PATCH 08/13] vrange: Send SIGBUS when user try to access purged page Date: Mon, 10 Jun 2013 18:12:14 -0700 Message-Id: <1370913139-9320-9-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1370913139-9320-1-git-send-email-john.stultz@linaro.org> References: <1370913139-9320-1-git-send-email-john.stultz@linaro.org> X-Gm-Message-State: ALoCoQneiAn+kwAWLX1LldO4RO0NR0PULrwo/kCpvx5U7MZUkAsfX+4PtVFeOMxFk8aEdMCODTiB X-Original-Sender: john.stultz@linaro.org X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 2607:f8b0:400c:c01::22c is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , From: Minchan Kim By vrange(2) semantic, user should see SIGBUG if he try to access purged page without vrange(...VRANGE_NOVOLATILE). This patch implements it. I reused PSE bit for quick prototype without enough considering so need time to see what's empty bit and I am surely missing many places to handle vrange pte bit. I should investigate all of pte handling places, especially pte_none case. TODO Signed-off-by: Minchan Kim Signed-off-by: John Stultz --- arch/x86/include/asm/pgtable_types.h | 2 ++ include/asm-generic/pgtable.h | 11 +++++++++++ include/linux/vrange.h | 2 ++ mm/memory.c | 23 +++++++++++++++++++++-- mm/vrange.c | 24 +++++++++++++++++++++++- 5 files changed, 59 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index e642300..d7ea6a0 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -64,6 +64,8 @@ #define _PAGE_FILE (_AT(pteval_t, 1) << _PAGE_BIT_FILE) #define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE) +#define _PAGE_VRANGE _PAGE_BIT_PSE + /* * _PAGE_NUMA indicates that this page will trigger a numa hinting * minor page fault to gather numa placement statistics (see diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index a59ff51..91e8f6f 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -479,6 +479,17 @@ static inline unsigned long my_zero_pfn(unsigned long addr) #ifdef CONFIG_MMU +static inline pte_t pte_mkvrange(pte_t pte) +{ + pte = pte_set_flags(pte, _PAGE_VRANGE); + return pte_clear_flags(pte, _PAGE_PRESENT); +} + +static inline int pte_vrange(pte_t pte) +{ + return ((pte_flags(pte) | _PAGE_PRESENT) == _PAGE_VRANGE); +} + #ifndef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_trans_huge(pmd_t pmd) { diff --git a/include/linux/vrange.h b/include/linux/vrange.h index cbb609a..75754d1 100644 --- a/include/linux/vrange.h +++ b/include/linux/vrange.h @@ -41,6 +41,8 @@ int discard_vpage(struct page *page); bool vrange_address(struct mm_struct *mm, unsigned long start, unsigned long end); +extern bool is_purged_vrange(struct mm_struct *mm, unsigned long address); + #else static inline void vrange_init(void) {}; diff --git a/mm/memory.c b/mm/memory.c index 6dc1882..f9bc45c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -59,6 +59,7 @@ #include #include #include +#include #include #include @@ -841,7 +842,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, /* pte contains position in swap or file, so copy. */ if (unlikely(!pte_present(pte))) { - if (!pte_file(pte)) { + if (!pte_file(pte) && !pte_vrange(pte)) { swp_entry_t entry = pte_to_swp_entry(pte); if (swap_duplicate(entry) < 0) @@ -1181,7 +1182,7 @@ again: if (pte_file(ptent)) { if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) print_bad_pte(vma, addr, ptent, NULL); - } else { + } else if (!pte_vrange(ptent)) { swp_entry_t entry = pte_to_swp_entry(ptent); if (!non_swap_entry(entry)) @@ -3716,9 +3717,27 @@ int handle_pte_fault(struct mm_struct *mm, return do_linear_fault(mm, vma, address, pte, pmd, flags, entry); } +anon: return do_anonymous_page(mm, vma, address, pte, pmd, flags); } + + if (unlikely(pte_vrange(entry))) { + if (!is_purged_vrange(mm, address)) { + /* zap pte */ + ptl = pte_lockptr(mm, pmd); + spin_lock(ptl); + if (unlikely(!pte_same(*pte, entry))) + goto unlock; + flush_cache_page(vma, address, pte_pfn(*pte)); + ptep_clear_flush(vma, address, pte); + pte_unmap_unlock(pte, ptl); + goto anon; + } + + return VM_FAULT_SIGBUS; + } + if (pte_file(entry)) return do_nonlinear_fault(mm, vma, address, pte, pmd, flags, entry); diff --git a/mm/vrange.c b/mm/vrange.c index 3589d10..603057e 100644 --- a/mm/vrange.c +++ b/mm/vrange.c @@ -477,7 +477,9 @@ int try_to_discard_one(struct page *page, struct vm_area_struct *vma, present = pte_present(*pte); flush_cache_page(vma, address, page_to_pfn(page)); - pteval = ptep_clear_flush(vma, address, pte); + + ptep_clear_flush(vma, address, pte); + pteval = pte_mkvrange(*pte); update_hiwater_rss(mm); dec_mm_counter(mm, MM_ANONPAGES); @@ -491,6 +493,7 @@ int try_to_discard_one(struct page *page, struct vm_area_struct *vma, BUG_ON(1); } + set_pte_at(mm, address, pte, pteval); pte_unmap_unlock(pte, ptl); mmu_notifier_invalidate_page(mm, address); ret = 1; @@ -588,3 +591,22 @@ int discard_vpage(struct page *page) return 0; } +bool is_purged_vrange(struct mm_struct *mm, unsigned long address) +{ + struct vrange_root *vroot = &mm->vroot; + struct interval_tree_node *node; + struct vrange *range; + bool ret = false; + + vrange_lock(vroot); + node = interval_tree_iter_first(&vroot->v_rb, address, + address + PAGE_SIZE - 1); + if (node) { + range = container_of(node, struct vrange, node); + if (range->purged) + ret = true; + } + vrange_unlock(vroot); + return ret; +} +