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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E562C4332F for ; Fri, 9 Dec 2022 14:40:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229962AbiLIOkj (ORCPT ); Fri, 9 Dec 2022 09:40:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229902AbiLIOka (ORCPT ); Fri, 9 Dec 2022 09:40:30 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id BB96727DFC for ; Fri, 9 Dec 2022 06:40:29 -0800 (PST) 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 4C06C23A; Fri, 9 Dec 2022 06:40:36 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.41.252]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1CA453F73D; Fri, 9 Dec 2022 06:40:27 -0800 (PST) Date: Fri, 9 Dec 2022 14:40:25 +0000 From: Mark Rutland To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 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: References: <20221209143402.3332369-1-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221209143402.3332369-1-ardb@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 09, 2022 at 03:34:02PM +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. > > Signed-off-by: Ard Biesheuvel My bad; sorry about this, and thanks for the fix! Acked-by: Mark Rutland We should probably also add: Fixes: 26299b3f6ba26bfc ("ftrace: arm64: move from REGS to ARGS") Mark. > --- > 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 >