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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9C8BEB64DD for ; Mon, 14 Aug 2023 21:10:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232660AbjHNVJq (ORCPT ); Mon, 14 Aug 2023 17:09:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232822AbjHNVJb (ORCPT ); Mon, 14 Aug 2023 17:09:31 -0400 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADD15E5E for ; Mon, 14 Aug 2023 14:09:30 -0700 (PDT) Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-1bdb801c667so28440215ad.1 for ; Mon, 14 Aug 2023 14:09:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1692047370; x=1692652170; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=4PuvQpJrJqrNy7astmt5IVebXoF5w/a9tG+pRmbryqo=; b=kxnjP4K14WJSvLPejXWZrEY2njof9Zmsz4pFZ+tWjEdwYQPwfyIy1Mbf1S1FDVBq9l 9MWRs8VsKnOSdrE1QbDjEkJezJ9LJ2HWu8lANe7NqKHvNsNkhjfFXFiphBgOObgoJjGR Gfg8K0Q8n07N+ZzpKj9/KJ0ZLGM2DIevYNjic= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692047370; x=1692652170; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4PuvQpJrJqrNy7astmt5IVebXoF5w/a9tG+pRmbryqo=; b=W8e7l/7a1861GpGqjEezg7oaH28qmgfModWLyEqCYvcvRT3RCGc45/Z9+YNV1vhNEl WdKG8Fan3poph25aB2CA11ho2Qa4erK+8LZuoMUPECV051s2AktYuaKVc2qTtzAcEbZk r3Oy8zBm1/3ka/AI4gFmsbnKATnBSYx5A3Nxdn2pjjXYiHz7+I1RPbysCQUj1Uggy5In +BDo2ZrqB4S5bzxiJOnzTreWmczj3yZGLCsl6OEOlAliL6YC1OKjcwlBpwdrtCsHAHmO ybyJk7uWvTZJj8gRkcsjrKoT6UiVeGLmEgEjrOr2zqGZeVvdrpZ+6UjIWF8bQJuHK8uu zVpA== X-Gm-Message-State: AOJu0YxQqEJLgPR0451Fhb8uX55pX31xnVnwuCcYjBCSf57DhUGRlaw2 5CNrepjt2QU7OF4+PZjW5EJDrw== X-Google-Smtp-Source: AGHT+IFYeDWP5PYNKsk0YR+BiKLZK4N4Rwa0P0VjZkZ6hsNlrW8rO0WgiTO5nntV4saLBRmYH2B/dg== X-Received: by 2002:a17:902:ee44:b0:1b0:6038:2982 with SMTP id 4-20020a170902ee4400b001b060382982mr10965327plo.41.1692047370203; Mon, 14 Aug 2023 14:09:30 -0700 (PDT) Received: from www.outflux.net (198-0-35-241-static.hfc.comcastbusiness.net. [198.0.35.241]) by smtp.gmail.com with ESMTPSA id iw3-20020a170903044300b001b857352285sm9941444plb.247.2023.08.14.14.09.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 14:09:29 -0700 (PDT) Date: Mon, 14 Aug 2023 14:09:29 -0700 From: Kees Cook To: Sami Tolvanen Cc: Nathan Chancellor , Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , Deepak Gupta , Nick Desaulniers , Fangrui Song , linux-riscv@lists.infradead.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/5] riscv: SCS support Message-ID: <202308141409.76B8A274BF@keescook> References: <20230811233556.97161-7-samitolvanen@google.com> <20230814175928.GA1028706@dev-arch.thelio-3990X> <202308141131.6B90A4205@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 14, 2023 at 01:18:30PM -0700, Sami Tolvanen wrote: > On Mon, Aug 14, 2023 at 11:57 AM Sami Tolvanen wrote: > > Looks like __builtin_frame_address behaves differently on RISC-V. > > After staring at the disassembly a bit, using > > __builtin_frame_address(0) - 1 instead of + 1 seems to yield correct > > results. > > Elliott was kind enough to point out to me off-list that this behavior > has been documented here: > > https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#frame-pointer-convention > > I'll include a patch to fix the test on RISC-V in the next version. Perfect! Thanks for figuring out the offset. :) -- Kees Cook