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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT 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 D3A04C433F4 for ; Mon, 24 Sep 2018 16:54:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 899092145D for ; Mon, 24 Sep 2018 16:54:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 899092145D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732851AbeIXW53 (ORCPT ); Mon, 24 Sep 2018 18:57:29 -0400 Received: from foss.arm.com ([217.140.101.70]:38802 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728436AbeIXW53 (ORCPT ); Mon, 24 Sep 2018 18:57:29 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0C14380D; Mon, 24 Sep 2018 09:54:25 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CDE1D3F5BD; Mon, 24 Sep 2018 09:54:23 -0700 (PDT) Date: Mon, 24 Sep 2018 17:54:21 +0100 From: Mark Rutland To: Jun Yao Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, james.morse@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap. Message-ID: <20180924165421.77bjq5m32h5w7ffh@lakrids.cambridge.arm.com> References: <20180917044333.30051-1-yaojun8558363@gmail.com> <20180917044333.30051-6-yaojun8558363@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180917044333.30051-6-yaojun8558363@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 17, 2018 at 12:43:32PM +0800, Jun Yao wrote: > Since we will move the swapper_pg_dir to rodata section, we need a > way to update it. The fixmap can handle it. When the swapper_pg_dir > needs to be updated, we map it dynamically. The map will be > canceled after the update is complete. In this way, we can defend > against KSMA(Kernel Space Mirror Attack). > > Signed-off-by: Jun Yao > --- > arch/arm64/include/asm/pgtable.h | 38 ++++++++++++++++++++++++++------ > arch/arm64/mm/mmu.c | 25 +++++++++++++++++++-- > 2 files changed, 54 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b11d6fc62a62..9e643fc2453d 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -429,8 +429,29 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PUD_TYPE_TABLE) > #endif > > +extern pgd_t init_pg_dir[PTRS_PER_PGD]; > +extern pgd_t init_pg_end[]; > +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; > +extern pgd_t swapper_pg_end[]; > +extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; > +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; > + > +extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd); > + > +static inline bool in_swapper_pgdir(void *addr) > +{ > + return ((unsigned long)addr & PAGE_MASK) == > + ((unsigned long)swapper_pg_dir & PAGE_MASK); > +} > + > static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) > { > +#ifdef __PAGETABLE_PMD_FOLDED > + if (in_swapper_pgdir(pmdp)) { > + set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); > + return; > + } > +#endif So that we can get consistent build coverage, could we make this: if (__is_defined(__PAGETABLE_PMD_FOLDED) && in_swapper_pgdir(pmdp)) { set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); return; } > WRITE_ONCE(*pmdp, pmd); > > if (pmd_valid(pmd)) > @@ -484,6 +505,12 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > > static inline void set_pud(pud_t *pudp, pud_t pud) > { > +#ifdef __PAGETABLE_PUD_FOLDED > + if (in_swapper_pgdir(pudp)) { > + set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); > + return; > + } > +#endif ... and likewise: if (__is_enabled(__PAGETABLE_PUD_FOLDED) && in_swapper_pgdir(pudp)) { set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); return; } Thanks, Mark. From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Mon, 24 Sep 2018 17:54:21 +0100 Subject: [PATCH v5 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap. In-Reply-To: <20180917044333.30051-6-yaojun8558363@gmail.com> References: <20180917044333.30051-1-yaojun8558363@gmail.com> <20180917044333.30051-6-yaojun8558363@gmail.com> Message-ID: <20180924165421.77bjq5m32h5w7ffh@lakrids.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Sep 17, 2018 at 12:43:32PM +0800, Jun Yao wrote: > Since we will move the swapper_pg_dir to rodata section, we need a > way to update it. The fixmap can handle it. When the swapper_pg_dir > needs to be updated, we map it dynamically. The map will be > canceled after the update is complete. In this way, we can defend > against KSMA(Kernel Space Mirror Attack). > > Signed-off-by: Jun Yao > --- > arch/arm64/include/asm/pgtable.h | 38 ++++++++++++++++++++++++++------ > arch/arm64/mm/mmu.c | 25 +++++++++++++++++++-- > 2 files changed, 54 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b11d6fc62a62..9e643fc2453d 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -429,8 +429,29 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PUD_TYPE_TABLE) > #endif > > +extern pgd_t init_pg_dir[PTRS_PER_PGD]; > +extern pgd_t init_pg_end[]; > +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; > +extern pgd_t swapper_pg_end[]; > +extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; > +extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; > + > +extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd); > + > +static inline bool in_swapper_pgdir(void *addr) > +{ > + return ((unsigned long)addr & PAGE_MASK) == > + ((unsigned long)swapper_pg_dir & PAGE_MASK); > +} > + > static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) > { > +#ifdef __PAGETABLE_PMD_FOLDED > + if (in_swapper_pgdir(pmdp)) { > + set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); > + return; > + } > +#endif So that we can get consistent build coverage, could we make this: if (__is_defined(__PAGETABLE_PMD_FOLDED) && in_swapper_pgdir(pmdp)) { set_swapper_pgd((pgd_t *)pmdp, __pgd(pmd_val(pmd))); return; } > WRITE_ONCE(*pmdp, pmd); > > if (pmd_valid(pmd)) > @@ -484,6 +505,12 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > > static inline void set_pud(pud_t *pudp, pud_t pud) > { > +#ifdef __PAGETABLE_PUD_FOLDED > + if (in_swapper_pgdir(pudp)) { > + set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); > + return; > + } > +#endif ... and likewise: if (__is_enabled(__PAGETABLE_PUD_FOLDED) && in_swapper_pgdir(pudp)) { set_swapper_pgd((pgd_t *)pudp, __pgd(pud_val(pud))); return; } Thanks, Mark.