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=-14.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 10519C43387 for ; Mon, 14 Jan 2019 09:35:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5BBE20659 for ; Mon, 14 Jan 2019 09:35:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cG3zM3rO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726584AbfANJfG (ORCPT ); Mon, 14 Jan 2019 04:35:06 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:43234 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726064AbfANJfF (ORCPT ); Mon, 14 Jan 2019 04:35:05 -0500 Received: by mail-io1-f67.google.com with SMTP id b23so17068196ios.10 for ; Mon, 14 Jan 2019 01:35:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=cG3zM3rOJqP9xq8n8LMwEKTXJUQ4xh2O+zaaNyos6gkTdiT0UhD5YRj4zebrVQCK79 lTszCU7lJZs+wRyNh/NZEjWDrwgO2XiRVx6xv0Ra/FQU9iclaLSOhmErIuO/HUVBzWr2 nP3swD1jtKwthtzn03IXwPV9QFMWMIlVuHp1iQ0d6KMQztjWe8TBkSZdAUMrRjMh6WUN nStPiAZ/dUsrozxjVmfHco6C7wBa+7K1swBrAUHWvFubg/nw/9+fY4NJgHI7e9+NBb5/ WSU1YAmgtOKm2strY0meX98AhNuQy8M3JmpV81bLo/b6PGT3C4i+VArU5y5WdeeW+yk+ q0SQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=Y3EwStg87R9NLL9B0EU3oNwpUUbYBIoiUijH3RkRFYeug9MiQjlsCPq2sJKcDe3eKv rbfbkIMpo1dNM0VMdXt4xNlc6oBJUPZbz+kQWa7nEPYnkxS3BtMTPWhC16LhJpkeOVZN 22p4RGHj/sshDuKY/AiGjLDZYQJ4jbsrO4XTdndGS2Of2dH38Taj3DQcEos0uUzv8OV6 bIlOto5zXLm3KuM5oTzoc1A/gIWqyBDII+7JUYzDY6+3pNpPQm3J+YQOJ9Ex9XeuEa61 ZzJpisAHRHtRsAP3Iyhhq6028jyLWiUNQlc5ACuejraFb26gbqQ9STU4Q/Si1LaZTO5V XgDg== X-Gm-Message-State: AJcUukfFupyeFef6Pi/0T5dBH/IzgZzN8FEGHM6skgv4U8LIWiYHWr3J 1ygqwqgMKFgkB/oe4WiYtGY98Nv6KiwUrYjIRhVXjg== X-Google-Smtp-Source: ALg8bN4Izjtfz8Gtik6EdgfSYlWSdQko5wrdsb98M1TQUO3p0k+tlZJCo9+xkTjkJb9IBNvEfs6/1WGPTInaXLkvDLg= X-Received: by 2002:a6b:fa01:: with SMTP id p1mr9451772ioh.271.1547458504276; Mon, 14 Jan 2019 01:35:04 -0800 (PST) MIME-Version: 1.0 References: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> In-Reply-To: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> From: Dmitry Vyukov Date: Mon, 14 Jan 2019 10:34:52 +0100 Message-ID: Subject: Re: [PATCH v3 1/3] powerpc/mm: prepare kernel for KAsan on PPC32 To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Nicholas Piggin , "Aneesh Kumar K.V" , Andrey Ryabinin , Alexander Potapenko , LKML , linuxppc-dev@lists.ozlabs.org, kasan-dev , Linux-MM Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 12, 2019 at 12:16 PM Christophe Leroy wrote: > > In kernel/cputable.c, explicitly use memcpy() in order > to allow GCC to replace it with __memcpy() when KASAN is > selected. > > Since commit 400c47d81ca38 ("powerpc32: memset: only use dcbz once cache is > enabled"), memset() can be used before activation of the cache, > so no need to use memset_io() for zeroing the BSS. > > Signed-off-by: Christophe Leroy > --- > arch/powerpc/kernel/cputable.c | 4 ++-- > arch/powerpc/kernel/setup_32.c | 6 ++---- > 2 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c > index 1eab54bc6ee9..84814c8d1bcb 100644 > --- a/arch/powerpc/kernel/cputable.c > +++ b/arch/powerpc/kernel/cputable.c > @@ -2147,7 +2147,7 @@ void __init set_cur_cpu_spec(struct cpu_spec *s) > struct cpu_spec *t = &the_cpu_spec; > > t = PTRRELOC(t); > - *t = *s; > + memcpy(t, s, sizeof(*t)); Hi Christophe, I understand why you are doing this, but this looks a bit fragile and non-scalable. This may not work with the next version of compiler, just different than yours version of compiler, clang, etc. Does using -ffreestanding and/or -fno-builtin-memcpy (-memset) help? If it helps, perhaps it makes sense to add these flags to KASAN_SANITIZE := n files. > *PTRRELOC(&cur_cpu_spec) = &the_cpu_spec; > } > @@ -2162,7 +2162,7 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset, > old = *t; > > /* Copy everything, then do fixups */ > - *t = *s; > + memcpy(t, s, sizeof(*t)); > > /* > * If we are overriding a previous value derived from the real > diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c > index 947f904688b0..5e761eb16a6d 100644 > --- a/arch/powerpc/kernel/setup_32.c > +++ b/arch/powerpc/kernel/setup_32.c > @@ -73,10 +73,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr) > { > unsigned long offset = reloc_offset(); > > - /* First zero the BSS -- use memset_io, some platforms don't have > - * caches on yet */ > - memset_io((void __iomem *)PTRRELOC(&__bss_start), 0, > - __bss_stop - __bss_start); > + /* First zero the BSS */ > + memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start); > > /* > * Identify the CPU type and fix up code sections > -- > 2.13.3 > 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=-14.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 54D9DC43387 for ; Mon, 14 Jan 2019 09:35:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EC63C20659 for ; Mon, 14 Jan 2019 09:35:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cG3zM3rO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC63C20659 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3BAC08E0003; Mon, 14 Jan 2019 04:35:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 368528E0002; Mon, 14 Jan 2019 04:35:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 259D38E0003; Mon, 14 Jan 2019 04:35:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-io1-f71.google.com (mail-io1-f71.google.com [209.85.166.71]) by kanga.kvack.org (Postfix) with ESMTP id F313A8E0002 for ; Mon, 14 Jan 2019 04:35:05 -0500 (EST) Received: by mail-io1-f71.google.com with SMTP id s5so19299078iom.22 for ; Mon, 14 Jan 2019 01:35:05 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=cGX65EU0xahjhYuRgC9suyy7fynXWl85qk8vyxHSocFyDptZp1I+kOvXwSEbPzFcFu jJ9IYphX6r9sP2g+KIbMPtC9JBma/UNnoi41wqnDaOpZGBhFguCcDWxPP4jUQW2xI8zC FpFEfL6sac/CE001Papw+IixIZenG2XpnpryPFD1NT/lT9yK02YQ2Isa7iRGyscVA31/ jCJnsv+Y1FaPmOhn5KM8VguonLSOQ8pnMpv+5Pa8jcIrf34bx8IFN1cmatWmA0L8nck9 oXk24Bu7zWIbE5x9ZQzn6c7mRY2xeJ2Wz9Ry62DKbeXt9rweolP1kjt3KexyBCp0USau 2G+A== X-Gm-Message-State: AJcUukee774BC4H1uXSlAtEsQOXloyQoWYzg2zMsbCt3TCqFs1v4nr4e IGFSeiejgvPrscOGTqRsiEE/TFEnWBnwNpkg1rWoQu29g9ZWQtv0uJelkKcqMG6K1x4CYrnt7XK 5JD2It/RNDZphDF9kHvTwvLG4wmT5C/ix7U1e5Vy0xDiseqK4d0NFeefzWwtA5p3pptQ96xSb8K S2BS87De+kltc8xwWUPc1Nprc7Nrx+w34g0RmawvwZd9qcFvJJxYcpPF7BHbso78vxepTymCFZd sgANqrTcZU702qUIVR/Vv/wax7oYBmgPoF7kdNM2ZDMFXgy/HS465+TzHsusTTkuKvM0gokAaVY 4swafp0eMkt27ACo6Zg+mhu0LprUTeNHlW95FEaA2Jvdsib3WEFdfKRlhOuYnzRlnW4w6M/w1gL B X-Received: by 2002:a05:660c:74b:: with SMTP id a11mr7294305itl.27.1547458505761; Mon, 14 Jan 2019 01:35:05 -0800 (PST) X-Received: by 2002:a05:660c:74b:: with SMTP id a11mr7294286itl.27.1547458504963; Mon, 14 Jan 2019 01:35:04 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547458504; cv=none; d=google.com; s=arc-20160816; b=n+zZNfK983rVjdFjxlOIk1TlGJr9m1QrmVSQOxFbBmgjcHvX07WMneijx3QqDIpw8v 9xz3M8KbVuCIhrWuhMQIowE67xYNupXXHDWWxn1oYOVmRtPrhjxuc+azclUuCHAYhU2u FB5LaP0XJm+8S4NwMhjCzB+cUCkCnlyR0/XZRF3W47RZVm5q/KtHtzd3vjd2r5qVSLeV ItHOB/hqM02k3QCi0PxUeqZOtRmK/guxV48PtycjWEhdKyoGcEAtZlpc3Bfly8tYIOCc 1pPKoDAUdihdcsTrZS9a57MTNHAAY5cqVYuD50WPOerIybvkytXgwV6Ocl3NST4OOva1 EAag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=EQIXso5FkSy4Aww1wmLwGjAqNhQ/pE667fljHLuSwjT7mx5HB3ocmKtwN92LzDZnn6 I5BRJBzpgUt0jS7LcrnDHCir3N4FKDtXZWACBRVHtsGjYcFkbveknrYkau0ovyqRQcdT OAEIc8UM/TvwVCyyqXiulzs/kgJNTCWL3OKK+fn8JeAwopTB8ZVdLQZ1NOL1ZdlRI+9I MAhFjVXePx2lZ6ZSsovUhbC5SUKqUcc2+nSO4HYLyeMV6P9HHIF9tHE8LiviDULOk0q0 QZBPEQ9UZaax4q333EgxGNjnzAQoFpWgRBstig9xy+V4Li8lgOKpfLD2JFBEvRTuC0lV GY3A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=cG3zM3rO; spf=pass (google.com: domain of dvyukov@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dvyukov@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id z4sor47489318iol.132.2019.01.14.01.35.04 for (Google Transport Security); Mon, 14 Jan 2019 01:35:04 -0800 (PST) Received-SPF: pass (google.com: domain of dvyukov@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=cG3zM3rO; spf=pass (google.com: domain of dvyukov@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dvyukov@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=cG3zM3rOJqP9xq8n8LMwEKTXJUQ4xh2O+zaaNyos6gkTdiT0UhD5YRj4zebrVQCK79 lTszCU7lJZs+wRyNh/NZEjWDrwgO2XiRVx6xv0Ra/FQU9iclaLSOhmErIuO/HUVBzWr2 nP3swD1jtKwthtzn03IXwPV9QFMWMIlVuHp1iQ0d6KMQztjWe8TBkSZdAUMrRjMh6WUN nStPiAZ/dUsrozxjVmfHco6C7wBa+7K1swBrAUHWvFubg/nw/9+fY4NJgHI7e9+NBb5/ WSU1YAmgtOKm2strY0meX98AhNuQy8M3JmpV81bLo/b6PGT3C4i+VArU5y5WdeeW+yk+ q0SQ== X-Google-Smtp-Source: ALg8bN4Izjtfz8Gtik6EdgfSYlWSdQko5wrdsb98M1TQUO3p0k+tlZJCo9+xkTjkJb9IBNvEfs6/1WGPTInaXLkvDLg= X-Received: by 2002:a6b:fa01:: with SMTP id p1mr9451772ioh.271.1547458504276; Mon, 14 Jan 2019 01:35:04 -0800 (PST) MIME-Version: 1.0 References: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> In-Reply-To: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> From: Dmitry Vyukov Date: Mon, 14 Jan 2019 10:34:52 +0100 Message-ID: Subject: Re: [PATCH v3 1/3] powerpc/mm: prepare kernel for KAsan on PPC32 To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Nicholas Piggin , "Aneesh Kumar K.V" , Andrey Ryabinin , Alexander Potapenko , LKML , linuxppc-dev@lists.ozlabs.org, kasan-dev , Linux-MM Content-Type: text/plain; charset="UTF-8" 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: Message-ID: <20190114093452.VNIHcTvhQwIw21CfEz06HNKSQnqNYJFrQypt67scznc@z> On Sat, Jan 12, 2019 at 12:16 PM Christophe Leroy wrote: > > In kernel/cputable.c, explicitly use memcpy() in order > to allow GCC to replace it with __memcpy() when KASAN is > selected. > > Since commit 400c47d81ca38 ("powerpc32: memset: only use dcbz once cache is > enabled"), memset() can be used before activation of the cache, > so no need to use memset_io() for zeroing the BSS. > > Signed-off-by: Christophe Leroy > --- > arch/powerpc/kernel/cputable.c | 4 ++-- > arch/powerpc/kernel/setup_32.c | 6 ++---- > 2 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c > index 1eab54bc6ee9..84814c8d1bcb 100644 > --- a/arch/powerpc/kernel/cputable.c > +++ b/arch/powerpc/kernel/cputable.c > @@ -2147,7 +2147,7 @@ void __init set_cur_cpu_spec(struct cpu_spec *s) > struct cpu_spec *t = &the_cpu_spec; > > t = PTRRELOC(t); > - *t = *s; > + memcpy(t, s, sizeof(*t)); Hi Christophe, I understand why you are doing this, but this looks a bit fragile and non-scalable. This may not work with the next version of compiler, just different than yours version of compiler, clang, etc. Does using -ffreestanding and/or -fno-builtin-memcpy (-memset) help? If it helps, perhaps it makes sense to add these flags to KASAN_SANITIZE := n files. > *PTRRELOC(&cur_cpu_spec) = &the_cpu_spec; > } > @@ -2162,7 +2162,7 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset, > old = *t; > > /* Copy everything, then do fixups */ > - *t = *s; > + memcpy(t, s, sizeof(*t)); > > /* > * If we are overriding a previous value derived from the real > diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c > index 947f904688b0..5e761eb16a6d 100644 > --- a/arch/powerpc/kernel/setup_32.c > +++ b/arch/powerpc/kernel/setup_32.c > @@ -73,10 +73,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr) > { > unsigned long offset = reloc_offset(); > > - /* First zero the BSS -- use memset_io, some platforms don't have > - * caches on yet */ > - memset_io((void __iomem *)PTRRELOC(&__bss_start), 0, > - __bss_stop - __bss_start); > + /* First zero the BSS */ > + memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start); > > /* > * Identify the CPU type and fix up code sections > -- > 2.13.3 > 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=-6.8 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 E8FB7C43387 for ; Mon, 14 Jan 2019 09:36:58 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2282520659 for ; Mon, 14 Jan 2019 09:36:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="cG3zM3rO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2282520659 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43dSzW36QczDqR5 for ; Mon, 14 Jan 2019 20:36:55 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=google.com (client-ip=2607:f8b0:4864:20::d41; helo=mail-io1-xd41.google.com; envelope-from=dvyukov@google.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="cG3zM3rO"; dkim-atps=neutral Received: from mail-io1-xd41.google.com (mail-io1-xd41.google.com [IPv6:2607:f8b0:4864:20::d41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43dSxY1nxYzDqQx for ; Mon, 14 Jan 2019 20:35:06 +1100 (AEDT) Received: by mail-io1-xd41.google.com with SMTP id m19so17099209ioh.3 for ; Mon, 14 Jan 2019 01:35:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=cG3zM3rOJqP9xq8n8LMwEKTXJUQ4xh2O+zaaNyos6gkTdiT0UhD5YRj4zebrVQCK79 lTszCU7lJZs+wRyNh/NZEjWDrwgO2XiRVx6xv0Ra/FQU9iclaLSOhmErIuO/HUVBzWr2 nP3swD1jtKwthtzn03IXwPV9QFMWMIlVuHp1iQ0d6KMQztjWe8TBkSZdAUMrRjMh6WUN nStPiAZ/dUsrozxjVmfHco6C7wBa+7K1swBrAUHWvFubg/nw/9+fY4NJgHI7e9+NBb5/ WSU1YAmgtOKm2strY0meX98AhNuQy8M3JmpV81bLo/b6PGT3C4i+VArU5y5WdeeW+yk+ q0SQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Pn0/rZ2B5GkSLOkvstRq19Y+ZB+KVKjQ5D4UTrTEcFQ=; b=fGkNyEvallsDxVNqHpqUlTazAhCY4uf9cYjLO4Koc8aKCB2GT3wr1QIIzTxOfI9sEm EUi/vH13gteAQeB6gvkFDPIlqgRlhXkKwKlB0iugWC892FcG4FUaImTZJJu+0XObI/Mg 5XvIRmmKsiWYtlQKhjqKchtsEwFLLQFYpI4F7SdJScRcMJPcgeqRXT7kbpofITGKnGGk YQzdPstgUxMEWyoBrnA7CD94rc0ayoVl7XO9ZMXk7iodG4Q1cOo4/RJmH2j+Pw6mOGlt TL/CBn4X7f+eOO9R3NNsVpjyrGYAwUka7E9nprhMFoRkYEi0howZyGa2C6mg1g0zX6l9 EQyQ== X-Gm-Message-State: AJcUukcl78sAlaakSKNEQ+2tWw6EyVxbXRavWQjIhL+fc/n77X61RYfW ReAYrOrvLSbT4lFzdskjcfOVgUd3n4v1camIbecQOA== X-Google-Smtp-Source: ALg8bN4Izjtfz8Gtik6EdgfSYlWSdQko5wrdsb98M1TQUO3p0k+tlZJCo9+xkTjkJb9IBNvEfs6/1WGPTInaXLkvDLg= X-Received: by 2002:a6b:fa01:: with SMTP id p1mr9451772ioh.271.1547458504276; Mon, 14 Jan 2019 01:35:04 -0800 (PST) MIME-Version: 1.0 References: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> In-Reply-To: <0c854dd6b110ac2b81ef1681f6e097f59f84af8b.1547289808.git.christophe.leroy@c-s.fr> From: Dmitry Vyukov Date: Mon, 14 Jan 2019 10:34:52 +0100 Message-ID: Subject: Re: [PATCH v3 1/3] powerpc/mm: prepare kernel for KAsan on PPC32 To: Christophe Leroy Content-Type: text/plain; charset="UTF-8" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: LKML , Nicholas Piggin , Linux-MM , Paul Mackerras , "Aneesh Kumar K.V" , Andrey Ryabinin , Alexander Potapenko , kasan-dev , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, Jan 12, 2019 at 12:16 PM Christophe Leroy wrote: > > In kernel/cputable.c, explicitly use memcpy() in order > to allow GCC to replace it with __memcpy() when KASAN is > selected. > > Since commit 400c47d81ca38 ("powerpc32: memset: only use dcbz once cache is > enabled"), memset() can be used before activation of the cache, > so no need to use memset_io() for zeroing the BSS. > > Signed-off-by: Christophe Leroy > --- > arch/powerpc/kernel/cputable.c | 4 ++-- > arch/powerpc/kernel/setup_32.c | 6 ++---- > 2 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c > index 1eab54bc6ee9..84814c8d1bcb 100644 > --- a/arch/powerpc/kernel/cputable.c > +++ b/arch/powerpc/kernel/cputable.c > @@ -2147,7 +2147,7 @@ void __init set_cur_cpu_spec(struct cpu_spec *s) > struct cpu_spec *t = &the_cpu_spec; > > t = PTRRELOC(t); > - *t = *s; > + memcpy(t, s, sizeof(*t)); Hi Christophe, I understand why you are doing this, but this looks a bit fragile and non-scalable. This may not work with the next version of compiler, just different than yours version of compiler, clang, etc. Does using -ffreestanding and/or -fno-builtin-memcpy (-memset) help? If it helps, perhaps it makes sense to add these flags to KASAN_SANITIZE := n files. > *PTRRELOC(&cur_cpu_spec) = &the_cpu_spec; > } > @@ -2162,7 +2162,7 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset, > old = *t; > > /* Copy everything, then do fixups */ > - *t = *s; > + memcpy(t, s, sizeof(*t)); > > /* > * If we are overriding a previous value derived from the real > diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c > index 947f904688b0..5e761eb16a6d 100644 > --- a/arch/powerpc/kernel/setup_32.c > +++ b/arch/powerpc/kernel/setup_32.c > @@ -73,10 +73,8 @@ notrace unsigned long __init early_init(unsigned long dt_ptr) > { > unsigned long offset = reloc_offset(); > > - /* First zero the BSS -- use memset_io, some platforms don't have > - * caches on yet */ > - memset_io((void __iomem *)PTRRELOC(&__bss_start), 0, > - __bss_stop - __bss_start); > + /* First zero the BSS */ > + memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start); > > /* > * Identify the CPU type and fix up code sections > -- > 2.13.3 >