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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A8CEDC433E2 for ; Mon, 7 Sep 2020 21:47:49 +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 5A23E20768 for ; Mon, 7 Sep 2020 21:47:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pzhPNgUY"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Sv/zd04k" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A23E20768 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+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=dwxDlFrvI90HsHqF/UC9gTuH0sPrBmcpDpAcanTzfFY=; b=pzhPNgUYV/b9yN9Qbuiit/rly ETcdOB50ea8aeZr9lpebm7pdcU1TdRqEJ6or8zlPL2cp5fKhbruHOqaZ0ROomziHWEPCAZSwKCUfU /0oIoqhesmbhE2PHA0KgpzAHOoSxoUoe85dgxD3sLRFCoaCgDFAHjxi/17CoKi/zalqZBS+ByCXrJ FmgGdRWEKWCeCcAQxGai2cQ+wQu9i0lsEbS+GFJgmNVrM/kXVL+1jJ64eYOTPoqjJxV8wjq3Q2Gca iE6owrwJLgMCb8pHvVf8SZexbUDE56BM2WfdIgzGpwfzcG/vgGH7WrpCWoscwTa94u9OiYEnMnt4f drTytVxqA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFOxn-0007YM-Qv; Mon, 07 Sep 2020 21:46:11 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFOxZ-0007Ti-HQ for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2020 21:46:02 +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 C8D33206B5; Mon, 7 Sep 2020 21:45:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599515156; bh=CduuUnQHn0IkostwwcGeQpXiHS7H1RM1LlsOcbyEgj8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Sv/zd04kTzpB3TOKHcykDB1WwF0MH2Vt415NLNWa3Ejm2Ezx4AsGBqVJvI4FSPt8s S/TCe9esKYAabyHW82jvJ3uGG7QhysmhcB/bd2U3grmppagsO7+UeL5WNvNe5TFDqk BxSJFrdj0d5kAt7qr79aun9Vj4nK/Cl4VZQqfEOw= Date: Mon, 7 Sep 2020 22:45:51 +0100 From: Will Deacon To: Amit Daniel Kachhap Subject: Re: [PATCH v6 1/6] arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions Message-ID: <20200907214551.GD13815@willie-the-truck> References: <20200904104209.32385-1-amit.kachhap@arm.com> <20200904104209.32385-2-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200904104209.32385-2-amit.kachhap@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-20200907_174557_731290_FDA8F752 X-CRM114-Status: GOOD ( 18.52 ) 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: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Vincenzo Frascino , Dave Martin , 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 Fri, Sep 04, 2020 at 04:12:04PM +0530, Amit Daniel Kachhap wrote: > Currently the ARMv8.3-PAuth combined branch instructions (braa, retaa > etc.) are not simulated for out-of-line execution with a handler. Hence the > uprobe of such instructions leads to kernel warnings in a loop as they are > not explicitly checked and fall into INSN_GOOD categories. Other combined > instructions like LDRAA and LDRBB can be probed. > > The issue of the combined branch instructions is fixed by adding > definitions of all such instructions and rejecting their probes. > > Warning log: > WARNING: CPU: 5 PID: 249 at arch/arm64/kernel/probes/uprobes.c:182 uprobe_single_step_handler+0x34/0x50 > Modules linked in: > CPU: 5 PID: 249 Comm: func Tainted: G W 5.8.0-rc4-00005-ge658591d66d1-dirty #160 > Hardware name: Foundation-v8A (DT) > pstate: 204003c9 (nzCv DAIF +PAN -UAO BTYPE=--) > pc : uprobe_single_step_handler+0x34/0x50 > lr : single_step_handler+0x70/0xf8 > sp : ffff800012afbe30 > x29: ffff800012afbe30 x28: ffff000879f00ec0 > x27: 0000000000000000 x26: 0000000000000000 > x25: 0000000000000000 x24: 0000000000000000 > x23: 0000000060001000 x22: 00000000cb000022 > x21: ffff800011fc5a68 x20: ffff800012afbec0 > x19: ffff800011fc86c0 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 > x15: 0000000000000000 x14: 0000000000000000 > x13: 0000000000000000 x12: 0000000000000000 > x11: 0000000000000000 x10: 0000000000000000 > x9 : ffff800010085d50 x8 : 0000000000000000 > x7 : 0000000000000000 x6 : ffff800011fba9c0 > x5 : ffff800011fba000 x4 : ffff800012283070 > x3 : ffff8000100a78e0 x2 : 00000000004005f0 > x1 : 0000fffffffff008 x0 : ffff800012afbec0 > Call trace: > uprobe_single_step_handler+0x34/0x50 > single_step_handler+0x70/0xf8 > do_debug_exception+0xb8/0x130 > el0_sync_handler+0x7c/0x188 > el0_sync+0x158/0x180 > > Fixes: 74afda4016a7 ("arm64: compile the kernel with ptrauth return address signing") > Fixes: 04ca3204fa09 ("arm64: enable pointer authentication") > Signed-off-by: Amit Daniel Kachhap > Reviewed-by: Dave Martin > --- > Changes since v5: > * Slight change in commit log. > * Added Reviewed-by. > > arch/arm64/include/asm/insn.h | 12 ++++++++++++ > arch/arm64/kernel/insn.c | 14 ++++++++++++-- > arch/arm64/kernel/probes/decode-insn.c | 4 +++- > 3 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h > index 0bc46149e491..324234068fee 100644 > --- a/arch/arm64/include/asm/insn.h > +++ b/arch/arm64/include/asm/insn.h > @@ -359,9 +359,21 @@ __AARCH64_INSN_FUNCS(brk, 0xFFE0001F, 0xD4200000) > __AARCH64_INSN_FUNCS(exception, 0xFF000000, 0xD4000000) > __AARCH64_INSN_FUNCS(hint, 0xFFFFF01F, 0xD503201F) > __AARCH64_INSN_FUNCS(br, 0xFFFFFC1F, 0xD61F0000) > +__AARCH64_INSN_FUNCS(braaz, 0xFFFFFC1F, 0xD61F081F) > +__AARCH64_INSN_FUNCS(brabz, 0xFFFFFC1F, 0xD61F0C1F) > +__AARCH64_INSN_FUNCS(braa, 0xFFFFFC00, 0xD71F0800) > +__AARCH64_INSN_FUNCS(brab, 0xFFFFFC00, 0xD71F0C00) When do we need to distinguish these variants? Can we modify the mask/value pair so that we catch bra* in one go? That would match how they are documented in the Arm ARM. > __AARCH64_INSN_FUNCS(blr, 0xFFFFFC1F, 0xD63F0000) > +__AARCH64_INSN_FUNCS(blraaz, 0xFFFFFC1F, 0xD63F081F) > +__AARCH64_INSN_FUNCS(blrabz, 0xFFFFFC1F, 0xD63F0C1F) > +__AARCH64_INSN_FUNCS(blraa, 0xFFFFFC00, 0xD73F0800) > +__AARCH64_INSN_FUNCS(blrab, 0xFFFFFC00, 0xD73F0C00) Same here for blra* > __AARCH64_INSN_FUNCS(ret, 0xFFFFFC1F, 0xD65F0000) > +__AARCH64_INSN_FUNCS(retaa, 0xFFFFFFFF, 0xD65F0BFF) > +__AARCH64_INSN_FUNCS(retab, 0xFFFFFFFF, 0xD65F0FFF) > __AARCH64_INSN_FUNCS(eret, 0xFFFFFFFF, 0xD69F03E0) > +__AARCH64_INSN_FUNCS(eretaa, 0xFFFFFFFF, 0xD69F0BFF) > +__AARCH64_INSN_FUNCS(eretab, 0xFFFFFFFF, 0xD69F0FFF) ... and here for ereta*. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel