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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id AB1CEC4332F for ; Sun, 11 Dec 2022 03:28:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Mime-Version:References:In-Reply-To: Message-Id:Subject:Cc: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=Q9eFME1/xuu2nEflOIQ4HL5smSS+P2KGAjE9oZrTGRI=; b=IGGhuO07CC0hQw Dutz4ekXIGEkHt/wXRFz+FVPnM4nVd1RaYBKBGWLiSiHiuRjqdQum+6Wmed+ssTM1OebL2XNS1+vW K+sn+DXTWP0L/Du2bftTkC52DqRMzI0rkPW0ggsLJ5ZGApFauIC9Y7i1A+Jb+wYNCXd0Bg1FV1rYJ G93YXmprbuL4Oi0Em+Rtz+DvkMta6aIDJfXCoebLfDI/sZBESLnGhl4amAjDA72HnBBFFfOvyRSWL 7d9CxGqSCMTf29+8k/YgAweUxtNb7qHXCn38KZ5nbVGxMI9Smlt3r+6+0i6nYrmP5QxfwXGVMyZ9f mK3eoLaLvRxqO9UM9YkA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p4D08-00BEDS-Vt; Sun, 11 Dec 2022 03:27:41 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p4D06-00BEBE-40 for linux-arm-kernel@lists.infradead.org; Sun, 11 Dec 2022 03:27:39 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7E874B80943; Sun, 11 Dec 2022 03:27:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86343C433EF; Sun, 11 Dec 2022 03:27:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670729255; bh=SLRW9XaslzwlpQy6leJBYpMTuYIaNwDRf33UV6+Ao14=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=idDjc3uCqWJjnZF16XCZDJO66hS7lkkDiIcGq6/UKMwWocZcnfuiSaKLZkDMKJYlI 4g/U0GeRdgDdQ32dXwkTOZ1ZC34UeGWlAQGu9maCWgA9eK/nzySbCVrLWM8a76pWVf wyrfKKFWmgDC2mvbP0rAylq8FsZGYZGXShJN9ljuP7e7tFoFSaWaFm/GGN1KDpl9OW C2IcsmI2F+8zk7v8v3KQPtp4rgAIREN3H64ano+Fep86knUPDQipY5X9iJrUpTrwbX fRFKDdOQUGPnCMq7CyN3rgsTHbaVS5xmnKOtKr492jtj2j0sMVbnITkTfKFJrd5euu 0FF+YLliePkhA== Date: Sun, 11 Dec 2022 12:27:31 +0900 From: Masami Hiramatsu (Google) To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, will@kernel.org, rostedt@goodmis.org, samitolvanen@google.com, keescook@chromium.org, mhiramat@kernel.org Subject: Re: [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack Message-Id: <20221211122731.f909ac15e227675229f03ecf@kernel.org> In-Reply-To: <20221209143402.3332369-1-ardb@kernel.org> References: <20221209143402.3332369-1-ardb@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221210_192738_337418_A9BCC293 X-CRM114-Status: GOOD ( 22.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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, 9 Dec 2022 15:34:02 +0100 Ard Biesheuvel wrote: > The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to > DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently > require the former in order to allow the function graph tracer to be > enabled in combination with shadow call stacks. This means that this is > no longer permitted at all, in spite of the fact that either flavour of > ftrace works perfectly fine in this combination. > > Given that arm64 is the only arch that implements shadow call stacks in > the first place, let's update the condition to just reflect the arm64 > change. When other architectures adopt shadow call stack support, this > can be revisited if needed. This brings a question. Is the SCS safe if kretprobe(rethook) is enabled? it also changes the stack entry after a calling function. Thank you, > > Signed-off-by: Ard Biesheuvel > --- > arch/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 072a1b39e3afd0d1..683f365b5e31c856 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -635,7 +635,7 @@ config ARCH_SUPPORTS_SHADOW_CALL_STACK > config SHADOW_CALL_STACK > bool "Shadow Call Stack" > depends on ARCH_SUPPORTS_SHADOW_CALL_STACK > - depends on DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER > + depends on DYNAMIC_FTRACE_WITH_ARGS || !FUNCTION_GRAPH_TRACER > help > This option enables the compiler's Shadow Call Stack, which > uses a shadow stack to protect function return addresses from > -- > 2.35.1 > -- Masami Hiramatsu (Google) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel