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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 F2297C352A3 for ; Tue, 11 Feb 2020 13:57:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1CDB2086A for ; Tue, 11 Feb 2020 13:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728874AbgBKN5f (ORCPT ); Tue, 11 Feb 2020 08:57:35 -0500 Received: from foss.arm.com ([217.140.110.172]:46444 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729986AbgBKN5d (ORCPT ); Tue, 11 Feb 2020 08:57:33 -0500 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 8CB6431B; Tue, 11 Feb 2020 05:57:32 -0800 (PST) Received: from [10.1.196.105] (eglon.cambridge.arm.com [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 541BF3F68F; Tue, 11 Feb 2020 05:57:30 -0800 (PST) Subject: Re: [PATCH v7 11/11] arm64: scs: add shadow stacks for SDEI To: Sami Tolvanen Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20191018161033.261971-1-samitolvanen@google.com> <20200128184934.77625-1-samitolvanen@google.com> <20200128184934.77625-12-samitolvanen@google.com> From: James Morse Message-ID: Date: Tue, 11 Feb 2020 13:57:29 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200128184934.77625-12-samitolvanen@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sami, On 28/01/2020 18:49, Sami Tolvanen wrote: > This change adds per-CPU shadow call stacks for the SDEI handler. > Similarly to how the kernel stacks are handled, we add separate shadow > stacks for normal and critical events. Reviewed-by: James Morse Tested-by: James Morse > diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c > index eaadf5430baa..dddb7c56518b 100644 > --- a/arch/arm64/kernel/scs.c > +++ b/arch/arm64/kernel/scs.c > +static int scs_alloc_percpu(unsigned long * __percpu *ptr, int cpu) > +{ > + unsigned long *p; > + > + p = __vmalloc_node_range(PAGE_SIZE, SCS_SIZE, > + VMALLOC_START, VMALLOC_END, > + GFP_SCS, PAGE_KERNEL, > + 0, cpu_to_node(cpu), > + __builtin_return_address(0)); (What makes this arch specific? arm64 has its own calls like this for the regular vmap stacks because it plays tricks with the alignment. Here the alignment requirement comes from the core SCS code... Would another architecture implement these scs_alloc_percpu()/scs_free_percpu() differently?) Thanks, James