From patchwork Thu Jul 27 17:03:55 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 9867401 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 797806038C for ; Thu, 27 Jul 2017 17:04:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 61A6928847 for ; Thu, 27 Jul 2017 17:04:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5638028845; Thu, 27 Jul 2017 17:04:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C43CF28845 for ; Thu, 27 Jul 2017 17:04:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=TQbQfaQ91mYHJOACW3ZIVcLOcx9XShonvPk1Kjx11EA=; b=Aqw O9XEsQ3PeEhrdvi9dzVYJAKiz2k6PAcq6v+O/C44eGsn43aHDJ6gAVrgBKJ7VyHDGjRRuMH+9owPc GzVX3vERxrCPxl6Ai3DzKC/m9LSWiDwuoBUudLFrJCK/uB+HE0b5zk8TOdnbajPPIdVNApHIIx6OA S9UHjHLU/6GTJ228cE0o49uTWz4BEdbbA3j7S6FIalpm2MDVSVIwIeuStsSIEKN6zk3gaGGTi+/ex BJjNwvaGLVkvsQ40moFJcTfbZCBsBT/9VIXigmOfVMa+3i7pvgUnBM6AJHDWk3MERewWc8TIbGusU BfM6z62drfEMjc1OYI/0XyklOqJwb4Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1damCr-0007OC-9a; Thu, 27 Jul 2017 17:04:13 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1damCn-0007NR-C3 for linux-arm-kernel@lists.infradead.org; Thu, 27 Jul 2017 17:04:11 +0000 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 EF84F2B; Thu, 27 Jul 2017 10:03:48 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BB93B3F577; Thu, 27 Jul 2017 10:03:48 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 932101AE0DBD; Thu, 27 Jul 2017 18:03:56 +0100 (BST) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64: mmu: Place guard page after mapping of kernel image Date: Thu, 27 Jul 2017 18:03:55 +0100 Message-Id: <1501175035-32460-1-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170727_100409_452064_22CE810B X-CRM114-Status: GOOD ( 10.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Will Deacon , Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The vast majority of virtual allocations in the vmalloc region are followed by a guard page, which can help to avoid overruning on vma into another, which may map a read-sensitive device. This patch adds a guard page to the end of the kernel image mapping (i.e. following the data/bss segments). Cc: Mark Rutland Cc: Ard Biesheuvel Signed-off-by: Will Deacon Reviewed-by: Ard Biesheuvel Acked-by: Mark Rutland --- arch/arm64/mm/mmu.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 23c2d89a362e..f1eb15e0e864 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -496,7 +496,7 @@ void mark_rodata_ro(void) static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end, pgprot_t prot, struct vm_struct *vma, - int flags) + int flags, unsigned long vm_flags) { phys_addr_t pa_start = __pa_symbol(va_start); unsigned long size = va_end - va_start; @@ -507,10 +507,13 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end, __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot, early_pgtable_alloc, flags); + if (!(vm_flags & VM_NO_GUARD)) + size += PAGE_SIZE; + vma->addr = va_start; vma->phys_addr = pa_start; vma->size = size; - vma->flags = VM_MAP; + vma->flags = VM_MAP | vm_flags; vma->caller = __builtin_return_address(0); vm_area_add_early(vma); @@ -541,14 +544,15 @@ static void __init map_kernel(pgd_t *pgd) * Only rodata will be remapped with different permissions later on, * all other segments are allowed to use contiguous mappings. */ - map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text, 0); + map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text, 0, + VM_NO_GUARD); map_kernel_segment(pgd, __start_rodata, __inittext_begin, PAGE_KERNEL, - &vmlinux_rodata, NO_CONT_MAPPINGS); + &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); map_kernel_segment(pgd, __inittext_begin, __inittext_end, text_prot, - &vmlinux_inittext, 0); + &vmlinux_inittext, 0, VM_NO_GUARD); map_kernel_segment(pgd, __initdata_begin, __initdata_end, PAGE_KERNEL, - &vmlinux_initdata, 0); - map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data, 0); + &vmlinux_initdata, 0, VM_NO_GUARD); + map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) { /*