From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33997C433ED for ; Fri, 9 Apr 2021 15:16:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05A1E610CF for ; Fri, 9 Apr 2021 15:16:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234057AbhDIPQs (ORCPT ); Fri, 9 Apr 2021 11:16:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234018AbhDIPQk (ORCPT ); Fri, 9 Apr 2021 11:16:40 -0400 Received: from mail-lf1-x12b.google.com (mail-lf1-x12b.google.com [IPv6:2a00:1450:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF029C061760 for ; Fri, 9 Apr 2021 08:16:25 -0700 (PDT) Received: by mail-lf1-x12b.google.com with SMTP id 12so10170895lfq.13 for ; Fri, 09 Apr 2021 08:16:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=2Z/yYSNAypvLdcknWdN0jFKSTVmGg2skM4f2irCe/+4=; b=F6WCL+h0/tP9in+fDqwT0cY3mMu3UVsk7LgdOGzIIy+irtGR0w2X9fIQdkSR7xRD8r qP/FA+1JIVvPJF8oaP10W0+t4M3RUjWjn9WFbABDNr8k5khi8T1y8jpPH9Uuuxp7jJQp li5UhFx16sJQYASv+x53DDCGLFxBuKWm4ncrsUyJ+s9Rd/Jld4NbDsr+ZIb351AKQCDI /Aw7CgUuxAfkKgkUgZEU/yBDqwNItOTV/h5C5u9vhJGK8p7SfQeWaob4fAnHSgxiwnTF S7UH1hSKQdncOqaMF1+rDkbOh1HBu2G+1tsKM+xL9G+Hu0cc6rT74yo8tFIyU1xbLTiv ZLnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=2Z/yYSNAypvLdcknWdN0jFKSTVmGg2skM4f2irCe/+4=; b=rJek8WRA7wIU6bSvOcAk/lAg3xOg+Vl5th5BQb6cvEKQoWi58VUpZ2uv1YbfFSkAzO NOEb3l4DFSIOBA5VKu+oO3K0jECWzh7j7G1vqIhvtl8qcEKaeG/xMHarSe+O9ThjZ1FR Uy5aw8mJLAYtGEeWEFy8/SUXNRtL0VIoH+u+2v7t8k2i7Qj58moxlHbbdJDLQZRGK55w 4wah4Mk8A5idEf/gpDnlmPqaEzYxcC+LVDZpIsV+iIhWFRYSjOO7FNFjNgJFnoQTyJzz TmOaOI7ky+aKrHd/tXWYTlLHwC0JzclHsd1AJnAsFcmtNB7gAfRLqLmUpyVphiVGhPnF Lslg== X-Gm-Message-State: AOAM531hKkUYxrHs2p70vy5XclAithBihqJFZltWdGts8RrDTBphX2fD e3NNT6uVjDfDeMkMXb1hyZ8Cjg== X-Google-Smtp-Source: ABdhPJxZOdHJXf6KM2DKtMXusgwm4xwoirT3CFK/2cTbRJYimDigKyBqA3B926lUdKv5znBu6nRu7A== X-Received: by 2002:a05:6512:c27:: with SMTP id z39mr10687224lfu.244.1617981384391; Fri, 09 Apr 2021 08:16:24 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id e11sm299296ljj.59.2021.04.09.08.16.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Apr 2021 08:16:23 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 35536102498; Fri, 9 Apr 2021 18:16:23 +0300 (+03) Date: Fri, 9 Apr 2021 18:16:23 +0300 From: "Kirill A. Shutemov" To: Yu-cheng Yu Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang , "Kirill A . Shutemov" Subject: Re: [PATCH v24 15/30] x86/mm: Update maybe_mkwrite() for shadow stack Message-ID: <20210409151623.ffydw3ckzbl7qboo@box.shutemov.name> References: <20210401221104.31584-1-yu-cheng.yu@intel.com> <20210401221104.31584-16-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210401221104.31584-16-yu-cheng.yu@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 01, 2021 at 03:10:49PM -0700, Yu-cheng Yu wrote: > When serving a page fault, maybe_mkwrite() makes a PTE writable if its vma > has VM_WRITE. > > A shadow stack vma has VM_SHADOW_STACK. Its PTEs have _PAGE_DIRTY, but not > _PAGE_WRITE. In fork(), _PAGE_DIRTY is cleared to cause copy-on-write, > and in the page fault handler, _PAGE_DIRTY is restored and the shadow stack > page is writable again. > > Introduce an x86 version of maybe_mkwrite(), which sets proper PTE bits > according to VM flags. > > Apply the same changes to maybe_pmd_mkwrite(). > > Signed-off-by: Yu-cheng Yu > Cc: Kees Cook > Cc: Kirill A. Shutemov > --- > v24: > - Instead of doing arch_maybe_mkwrite(), overwrite maybe*_mkwrite() with x86 > versions. > - Change VM_SHSTK to VM_SHADOW_STACK. > > arch/x86/include/asm/pgtable.h | 8 ++++++++ > arch/x86/mm/pgtable.c | 20 ++++++++++++++++++++ > include/linux/mm.h | 2 ++ > mm/huge_memory.c | 2 ++ > 4 files changed, 32 insertions(+) > > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h > index 46d9394b884f..51cdf14488b7 100644 > --- a/arch/x86/include/asm/pgtable.h > +++ b/arch/x86/include/asm/pgtable.h > @@ -1686,6 +1686,14 @@ static inline bool arch_faults_on_old_pte(void) > return false; > } > > +#define maybe_mkwrite maybe_mkwrite > +extern pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma); > + > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +#define maybe_pmd_mkwrite maybe_pmd_mkwrite > +extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ Move it next to other THP-depended stuff. Otherwise looks good to me: Reviewed-by: Kirill A. Shutemov -- Kirill A. Shutemov