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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACBC1C636CC for ; Mon, 13 Feb 2023 12:05:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 406B26B0071; Mon, 13 Feb 2023 07:05:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3B6B26B0074; Mon, 13 Feb 2023 07:05:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 27E226B007E; Mon, 13 Feb 2023 07:05:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 17B4F6B0071 for ; Mon, 13 Feb 2023 07:05:24 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id EDB9E1A1402 for ; Mon, 13 Feb 2023 12:05:23 +0000 (UTC) X-FDA: 80462138526.30.CCCD915 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf19.hostedemail.com (Postfix) with ESMTP id BCBEE1A0027 for ; Mon, 13 Feb 2023 12:05:21 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Xi/TasoE"; spf=pass (imf19.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1676289921; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=LWwnaVVkHZ3TxJmod/JcejUfCO6MlIwBZ7PTsYBSbh0=; b=B2HZqBCAiCdcA0tcQ5idb+0ktid/99/ix5I/Pj1viSwGPn8C98Oo2VhGg3dP/2Ab3KKYoa Hr1kh9yhF8P5bS93CVO6x3Sxbnbuuq2wK0gnEgVYd15l4lVaAoh73QZQcDudaXBBIQsTMY w2NxBZ5TjSuVJtsuZ1B0mQnUDnQrTI4= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Xi/TasoE"; spf=pass (imf19.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1676289921; a=rsa-sha256; cv=none; b=DssO1P0JfQXfsh5doNO85McFruBjP3uj/NuZhnj50+xCSnYRgWMm67f9vs5+RH20PDitnW 9NksrmXgj4yU92xWFJjxOCcaVZ+YZyb2tFs6wf3tOS3VfhYflrsX/8SYweGPylkz+rIMe+ 0Wjz0vu6PEAXxisLfTja9Mtss+uLesg= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676289921; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LWwnaVVkHZ3TxJmod/JcejUfCO6MlIwBZ7PTsYBSbh0=; b=Xi/TasoEo4x/Etc4Fw08cTAeAVYG+mQf5cDlttMBSloohd7QUeCDbpiknsTrCetQbeNin/ hNFTAYYrM1yL9ycScFH599VtBnYxhaJWjYzfp7J2kFqohnFQhtz3wkfvrYKmtBUBj4et0k Nw/jQG56NHWRwRSv8QF4t10tuk9LTE8= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-64-qCQ1SkVXPjKzgMazR6Ic_A-1; Mon, 13 Feb 2023 07:05:19 -0500 X-MC-Unique: qCQ1SkVXPjKzgMazR6Ic_A-1 Received: by mail-wm1-f69.google.com with SMTP id j20-20020a05600c1c1400b003dc5dd44c0cso6048432wms.8 for ; Mon, 13 Feb 2023 04:05:19 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LWwnaVVkHZ3TxJmod/JcejUfCO6MlIwBZ7PTsYBSbh0=; b=KdpTuldXkriOYJky5nBgSUCv+taTbhMAmp4Rusx5GqngXSDBhXSPmSpnYkHAe2jOJS 3XARElGjl3NtHVuZ4BQ6+Zc4kCWzK0nVpl1cVKhzyll0lARwtjR8eYnP5jdEAKPIIbvh NADFAfLD1PnxuWMRCH+nO0lkUOd9/T1LZa0V/wZ/xUSVj24wXgLtCiThgZDD58lf2x/g o/FfXqPdDA6qj/Ut1G1cZ5XsfEsGh7rGsWSnIGfT836hDgER9OVTjRYpTSB7ZRsJTGdI jqYILYezp4aStv0Oq63SjxB98y+hwberePCjIC1ukrWOL9UGbXvCMYHYb8yo/BHT8R0A E57g== X-Gm-Message-State: AO0yUKXboCCHQvRuBwv6L3IpCZWrqAR89/wd8MrCl5KBhCxCi/c2Mo2z OEwI3KQ9SHFy3yR4b6COWNQGyI8U4tzT0Mtgb60dU6FsCo3dGY2Y4MGq9F0KoegkFKc8eIJ0nra SIpdZz0rmAYQ= X-Received: by 2002:a05:600c:704:b0:3df:d8c5:ec18 with SMTP id i4-20020a05600c070400b003dfd8c5ec18mr19163994wmn.13.1676289918370; Mon, 13 Feb 2023 04:05:18 -0800 (PST) X-Google-Smtp-Source: AK7set/TvfuGOjSTFiefa5UXGSPN6E8+yK5KOhZR7JAxIR0Nqy6UHZc73gYlaZp/IBbv/pX2T70tdA== X-Received: by 2002:a05:600c:704:b0:3df:d8c5:ec18 with SMTP id i4-20020a05600c070400b003dfd8c5ec18mr19163980wmn.13.1676289918082; Mon, 13 Feb 2023 04:05:18 -0800 (PST) Received: from ?IPV6:2003:cb:c705:6d00:5870:9639:1c17:8162? (p200300cbc7056d00587096391c178162.dip0.t-ipconnect.de. [2003:cb:c705:6d00:5870:9639:1c17:8162]) by smtp.gmail.com with ESMTPSA id y9-20020adfee09000000b002c550eb062fsm5407008wrn.14.2023.02.13.04.05.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Feb 2023 04:05:17 -0800 (PST) Message-ID: <2d6eefb8-c7c5-7d32-9a75-ae716f828cd9@redhat.com> Date: Mon, 13 Feb 2023 13:05:16 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH v1 RFC Zisslpcfi 11/20] mmu: maybe_mkwrite updated to manufacture shadow stack PTEs To: Deepak Gupta , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Andrew Morton Cc: linux-mm@kvack.org References: <20230213045351.3945824-1-debug@rivosinc.com> <20230213045351.3945824-12-debug@rivosinc.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230213045351.3945824-12-debug@rivosinc.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: BCBEE1A0027 X-Stat-Signature: 7m39qxgnybg77pwu1ydbg6zew8fpuazp X-Rspam-User: X-HE-Tag: 1676289921-894776 X-HE-Meta: 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 5PsgEM4W 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 13.02.23 05:53, Deepak Gupta wrote: > maybe_mkwrite creates PTEs with WRITE encodings for underlying arch if > VM_WRITE is turned on in vma->vm_flags. Shadow stack memory is a write- > able memory except it can only be written by certain specific > instructions. This patch allows maybe_mkwrite to create shadow stack PTEs > if vma is shadow stack VMA. Each arch can define which combination of VMA > flags means a shadow stack. > > Additionally pte_mkshdwstk must be provided by arch specific PTE > construction headers to create shadow stack PTEs. (in arch specific > pgtable.h). > > This patch provides dummy/stub pte_mkshdwstk if CONFIG_USER_SHADOW_STACK > is not selected. > > Signed-off-by: Deepak Gupta > --- > include/linux/mm.h | 23 +++++++++++++++++++++-- > include/linux/pgtable.h | 4 ++++ > 2 files changed, 25 insertions(+), 2 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 8f857163ac89..a7705bc49bfe 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1093,6 +1093,21 @@ static inline unsigned long thp_size(struct page *page) > void free_compound_page(struct page *page); > > #ifdef CONFIG_MMU > + > +#ifdef CONFIG_USER_SHADOW_STACK > +bool arch_is_shadow_stack_vma(struct vm_area_struct *vma); > +#endif > + > +static inline bool > +is_shadow_stack_vma(struct vm_area_struct *vma) > +{ > +#ifdef CONFIG_USER_SHADOW_STACK > + return arch_is_shadow_stack_vma(vma); > +#else > + return false; > +#endif > +} > + > /* > * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when > * servicing faults for write access. In the normal case, do always want > @@ -1101,8 +1116,12 @@ void free_compound_page(struct page *page); > */ > static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) > { > - if (likely(vma->vm_flags & VM_WRITE)) > - pte = pte_mkwrite(pte); > + if (likely(vma->vm_flags & VM_WRITE)) { > + if (unlikely(is_shadow_stack_vma(vma))) > + pte = pte_mkshdwstk(pte); > + else > + pte = pte_mkwrite(pte); > + } > return pte; Exactly what we are trying to avoid in the x86 approach right now. Please see the x86 series on details, we shouldn't try reinventing the wheel but finding a core-mm approach that fits multiple architectures. https://lkml.kernel.org/r/20230119212317.8324-1-rick.p.edgecombe@intel.com -- Thanks, David / dhildenb