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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 DBBC0C2BA2B for ; Thu, 9 Apr 2020 12:00:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B60D920768 for ; Thu, 9 Apr 2020 12:00:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726589AbgDIMA3 (ORCPT ); Thu, 9 Apr 2020 08:00:29 -0400 Received: from foss.arm.com ([217.140.110.172]:49250 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbgDIMA2 (ORCPT ); Thu, 9 Apr 2020 08:00:28 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0726730E; Thu, 9 Apr 2020 05:00:29 -0700 (PDT) Received: from [192.168.1.172] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EB4323F73D; Thu, 9 Apr 2020 05:00:27 -0700 (PDT) Subject: Re: [PATCH v2 1/6] arm64/vdso: use the fault callback to map vvar pages To: Andrei Vagin Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Dmitry Safonov References: <20200225073731.465270-1-avagin@gmail.com> <20200225073731.465270-2-avagin@gmail.com> From: Vincenzo Frascino Message-ID: Date: Thu, 9 Apr 2020 13:01:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200225073731.465270-2-avagin@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/25/20 7:37 AM, Andrei Vagin wrote: > This is required to support time namespaces where a time namespace data > page is different for each namespace. > > Signed-off-by: Andrei Vagin Reviewed-by: Vincenzo Frascino > --- > arch/arm64/kernel/vdso.c | 24 +++++++++++++++--------- > 1 file changed, 15 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c > index 354b11e27c07..290c36d74e03 100644 > --- a/arch/arm64/kernel/vdso.c > +++ b/arch/arm64/kernel/vdso.c > @@ -114,28 +114,32 @@ static int __vdso_init(enum arch_vdso_type arch_index) > PAGE_SHIFT; > > /* Allocate the vDSO pagelist, plus a page for the data. */ > - vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages + 1, > + vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages, > sizeof(struct page *), > GFP_KERNEL); > if (vdso_pagelist == NULL) > return -ENOMEM; > > - /* Grab the vDSO data page. */ > - vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data)); > - > - > /* Grab the vDSO code pages. */ > pfn = sym_to_pfn(vdso_lookup[arch_index].vdso_code_start); > > for (i = 0; i < vdso_lookup[arch_index].vdso_pages; i++) > - vdso_pagelist[i + 1] = pfn_to_page(pfn + i); > + vdso_pagelist[i] = pfn_to_page(pfn + i); > > - vdso_lookup[arch_index].dm->pages = &vdso_pagelist[0]; > - vdso_lookup[arch_index].cm->pages = &vdso_pagelist[1]; > + vdso_lookup[arch_index].cm->pages = vdso_pagelist; > > return 0; > } > > +static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, > + struct vm_area_struct *vma, struct vm_fault *vmf) > +{ > + if (vmf->pgoff == 0) > + return vmf_insert_pfn(vma, vmf->address, > + sym_to_pfn(vdso_data)); > + return VM_FAULT_SIGBUS; > +} > + > static int __setup_additional_pages(enum arch_vdso_type arch_index, > struct mm_struct *mm, > struct linux_binprm *bprm, > @@ -155,7 +159,7 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index, > } > > ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, > - VM_READ|VM_MAYREAD, > + VM_READ|VM_MAYREAD|VM_PFNMAP, > vdso_lookup[arch_index].dm); > if (IS_ERR(ret)) > goto up_fail; > @@ -215,6 +219,7 @@ static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = { > #ifdef CONFIG_COMPAT_VDSO > { > .name = "[vvar]", > + .fault = vvar_fault, > }, > { > .name = "[vdso]", > @@ -396,6 +401,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm, > static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = { > { > .name = "[vvar]", > + .fault = vvar_fault, > }, > { > .name = "[vdso]", > -- Regards, Vincenzo