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=-12.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 CBB72C47095 for ; Tue, 6 Oct 2020 10:44:45 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 5A451206F7 for ; Tue, 6 Oct 2020 10:44:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="yCWeP6LG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A451206F7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=9dnrzeYvOiT0M004n540sRUllf9AwwphN2A9K0KnuWc=; b=yCWeP6LGUGBNl0/C/j4OiahHS X3I6HngI4LEAX3hpw7UsQNIfS1Izn1egqo9APPF1Yo2tIgoM1puA9Y2KBVbKqpgIR+VXy5tsegi0k DKOg0X/ImI3fELfKJs9718/VMrcBdqLz4Xo5i/VAsuwyDbvgUm84WdBgOJosbQORwiSs/+f5W0xGX 7n7ispXlvWPpJCcn7AdzJsEV9nM/mlCovXQFC2xtQFztLUQXaIpPhdo348+zwyRSDr9fJq1eyh40d PRAW3Ihbg4l6CRJWz9me2Pz/eokfpG/hnKydR1EDhFJVRlkU+Kpw97eTk5tbeHE49IbDHwqHrsGWU lF5DM3kNw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kPkRI-0008Tt-Dr; Tue, 06 Oct 2020 10:43:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kPkRF-0008T7-N6 for linux-arm-kernel@lists.infradead.org; Tue, 06 Oct 2020 10:43:22 +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 3D0BD113E; Tue, 6 Oct 2020 03:43:18 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DD5AF3F66B; Tue, 6 Oct 2020 03:43:16 -0700 (PDT) Date: Tue, 6 Oct 2020 11:43:14 +0100 From: Dave Martin To: Catalin Marinas Subject: Re: [BUG][PATCH] crypto: arm64: Avoid indirect branch to bti_c Message-ID: <20201006104313.GX6642@arm.com> References: <20201006034854.2277538-1-jeremy.linton@arm.com> <20201006082748.GB25305@willie-the-truck> <20201006100121.GW6642@arm.com> <20201006102507.GA19213@gaia> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201006102507.GA19213@gaia> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201006_064321_850410_A0B9E8D4 X-CRM114-Status: GOOD ( 29.84 ) 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: herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, Jeremy Linton , ardb@kernel.org, broonie@kernel.org, linux-crypto@vger.kernel.org, Will Deacon , davem@davemloft.net, 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Oct 06, 2020 at 11:25:11AM +0100, Catalin Marinas wrote: > On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: > > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > > The AES code uses a 'br x7' as part of a function called by > > > > a macro. That branch needs a bti_j as a target. This results > > > > in a panic as seen below. Instead of trying to replace the branch > > > > target with a bti_jc, lets replace the indirect branch with a > > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > > sp : ffff80001052b730 > > > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > simd_skcipher_encrypt+0xc8/0xe0 > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > > test_skcipher+0xbc/0x120 > > > > alg_test_skcipher+0xa0/0x1b0 > > > > alg_test+0x3dc/0x47c > > > > cryptomgr_test+0x38/0x60 > > > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > > scripts will yell at us if we don't remove it. > > > > > > > Signed-off-by: Jeremy Linton > > > > --- > > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > > index b357164379f6..32f53ebe5e2c 100644 > > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > > > 0: mov bskey, x21 > > > > mov rounds, x22 > > > > - br x7 > > > > + ret > > > > Dang, replied on an old version. > > Which I ignored (by default, when the kbuild test robot complains ;)). > > > Since this is logically a tail call, could we simply be using br x16 or > > br x17 for this? > > > > The architecture makes special provision for that so that the compiler > > can generate tail-calls. > > So a "br x16" is compatible with a bti_c landing pad. I think it makes > more sense to keep it as a tail call. Just to be clear, I'm happy either way, but I thought it would make sense to point this out. Normally, "bti j" would be used just for weird stuff like jump tables, but .S files all count as "weird stuff" to some extent -- so there are no hard and fast rules. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel