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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=no 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 9F67CC433E0 for ; Tue, 19 May 2020 13:30:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 4B93320825 for ; Tue, 19 May 2020 13:30:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="MOAtuJfn"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="wgRaH1DR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B93320825 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=of1N4ITYUqlcSyY+TaKkvsKQOPsN432hy5J7WXxtX9o=; b=MOAtuJfnQ8X9ON jFvgo/yTEBHVSD667oH6nA5YWnouQzd9wW3TX7ii4vAkP+qynJ+Q09cqvmRwtwcsVeJRa+2Sg2wqJ liNM6hQTAc1mDBKhUIDSaeMCFki6zNbDLsnH9Zlx88edhFi+k/wTWBXAn3aqDCX4qVe5MzBT6gL/z dzb3NYsfM5VoAh8V5Cb4mLtW4PD1M3Ly+5bnaTSshGiZ1uJ8vDYUP3Ao/wPglRgt53ByPxH7keFjb rvJQT6MYgrh0cpKHu3Pi+ZrrNzC4zfE34Jawtr+LDC5F7ZL9sASW7S1SrBAo1BuKJWqz3LEnxlKOI gKMpE9bC0KTomwOtayzw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jb2Jp-0000j8-FE; Tue, 19 May 2020 13:30:05 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jb2Jl-0008T6-J5 for linux-arm-kernel@lists.infradead.org; Tue, 19 May 2020 13:30:03 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0CA4020829; Tue, 19 May 2020 13:29:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589895001; bh=tNCHKvOQltRdjqZGdQsgQweqdTCaMtSK23iuq29pVfo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wgRaH1DR+m6WF4pxjMX3N1SuD5kbrNqmTExYo0Bcx6amDNrCM/e/BwwA6rJLccJB0 cbVWMxfZ01vOzOWD29VHmtamajQfQn/vDmfMQXWm/zrHcurfhsNBd+YrdavsUfe1SU p7Y8UxXfzJQv6YLBLHx60bqg573+soYkjmuP5OKI= Date: Tue, 19 May 2020 14:29:56 +0100 From: Will Deacon To: Dave Martin Subject: Re: [PATCH 1/3] arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction Message-ID: <20200519132955.GA14570@willie-the-truck> References: <20200519121818.14511-1-will@kernel.org> <20200519121818.14511-2-will@kernel.org> <20200519132100.GD5031@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200519132100.GD5031@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200519_063001_674998_10AB9F01 X-CRM114-Status: UNSURE ( 9.04 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tamas Zsoldos , Mark Brown , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Daniel Kiss Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 19, 2020 at 02:21:01PM +0100, Dave Martin wrote: > On Tue, May 19, 2020 at 01:18:16PM +0100, Will Deacon wrote: > > For better or worse, GDB relies on the exact instruction sequence in the > > VDSO sigreturn trampoline in order to unwind from signals correctly. > > Are you sure? I'm struggling to find the relevant code in gdb. It looks pretty damning: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/aarch64-linux-tdep.c;h=34ba0d87baaff12f1f9711e777ab15a0a394f59b;hb=HEAD#l361 (and also look at struct tramp_frame). Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel