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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 ACEBBC3A5A9 for ; Mon, 4 May 2020 13:44:53 +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 7966F20757 for ; Mon, 4 May 2020 13:44:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rhXluhHB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7966F20757 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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=ggAARtcX7prEr3S73Bx0p2pZNof/rcGo0AQOmf2nBpw=; b=rhXluhHBIFCwmH TccfiLFzF42bY9t7EoUnYelYhF4et1KHVuR7Xj7ZqSpMeV+JoD87j+0pdeqODaDJa9kml7ugeVG1+ WJ/nP+5lRR2PhCOl84xwMOpAVG2TWmbg96ci2kh3WuCqirAco+hvtJaI2i7/1hMSLwlCJHvscR9aE h6VVIIt+7mGAz13RrtFS8gfEZTjqF5lNdqTETQTxg3mEFyzO9E1gyRVmuB9jOz+I2Gqr/S4UuO3E5 l3+vD5LrAFMqt3mHjjNBSJiF1SubAWA/xMcwlnuQk66+EN/M8R4j/Dtk2ei6XjJSn2C+fQ1HEYV8v I6MwG3f5lL/hIVTn5W/w==; 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 1jVbOs-0003w2-P5; Mon, 04 May 2020 13:44:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jVbOn-0003uz-Ov for linux-arm-kernel@lists.infradead.org; Mon, 04 May 2020 13:44:49 +0000 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 878C11FB; Mon, 4 May 2020 06:44:44 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.4.172]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6564B3F71F; Mon, 4 May 2020 06:44:43 -0700 (PDT) Date: Mon, 4 May 2020 14:44:40 +0100 From: Mark Rutland To: Mark Brown Subject: Re: [PATCH v4 3/4] arm64: insn: Don't assume unrecognized HINTs are skippable Message-ID: <20200504134440.GE73375@C02TD0UTHF1T.local> References: <20200504131326.18290-1-broonie@kernel.org> <20200504131326.18290-4-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200504131326.18290-4-broonie@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200504_064448_134843_C1526579 X-CRM114-Status: GOOD ( 17.70 ) 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: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org 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 Mon, May 04, 2020 at 02:13:25PM +0100, Mark Brown wrote: > Currently the kernel assumes that any HINT which it does not explicitly > recognise is skippable. This is not robust as new instructions may be > added which need special handling, and in any case software should only > be using explicit NOP instructions for deliberate NOPs. > > This has the effect of rendering PAC and BTI instructions unprobeable > which means that probes can't be inserted on the first instruction of > functions built with those features. > > Signed-off-by: Mark Brown > Acked-by: Catalin Marinas Acked-by: Mark Rutland Mark. > --- > arch/arm64/kernel/insn.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c > index 0829bb5b45ec..15c3f0643e3b 100644 > --- a/arch/arm64/kernel/insn.c > +++ b/arch/arm64/kernel/insn.c > @@ -57,14 +57,10 @@ bool __kprobes aarch64_insn_is_steppable_hint(u32 insn) > return false; > > switch (insn & 0xFE0) { > - case AARCH64_INSN_HINT_YIELD: > - case AARCH64_INSN_HINT_WFE: > - case AARCH64_INSN_HINT_WFI: > - case AARCH64_INSN_HINT_SEV: > - case AARCH64_INSN_HINT_SEVL: > - return false; > - default: > + case AARCH64_INSN_HINT_NOP: > return true; > + default: > + return false; > } > } > > -- > 2.20.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel