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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 9A515C43143 for ; Mon, 1 Oct 2018 09:09:45 +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 408512064A for ; Mon, 1 Oct 2018 09:09:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 408512064A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org 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 42NxLb1cYCzF38b for ; Mon, 1 Oct 2018 19:09:43 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: lists.ozlabs.org; spf=permerror (mailfrom) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42NxJf32KBzF35X for ; Mon, 1 Oct 2018 19:08:02 +1000 (AEST) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w9197LPO026802; Mon, 1 Oct 2018 04:07:21 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id w9197JJA026785; Mon, 1 Oct 2018 04:07:19 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 1 Oct 2018 04:07:19 -0500 From: Segher Boessenkool To: Bin Meng Subject: Re: [PATCH 2/2] powerpc/64: Increase stack redzone for 64-bit kernel to 512 bytes Message-ID: <20181001090719.GD23155@gate.crashing.org> References: <1538288720-14910-1-git-send-email-bmeng.cn@gmail.com> <1538288720-14910-2-git-send-email-bmeng.cn@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1538288720-14910-2-git-send-email-bmeng.cn@gmail.com> User-Agent: Mutt/1.4.2.3i 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: linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, Sep 29, 2018 at 11:25:20PM -0700, Bin Meng wrote: > /* > - * Size of redzone that userspace is allowed to use below the stack > + * Size of redzone that kernel/userspace is allowed to use below the stack > * pointer. This is 288 in the 64-bit big-endian ELF ABI, and 512 in > * the new ELFv2 little-endian ABI, so we allow the larger amount. > - * > - * For kernel code we allow a 288-byte redzone, in order to conserve > - * kernel stack space; gcc currently only uses 288 bytes, and will > - * hopefully allow explicit control of the redzone size in future. > */ Btw: patches welcome! This will never be useful for userland code, so no one in GCC land is looking at this (we did not even know it is wanted). Segher