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 45651C433EF for ; Tue, 22 Feb 2022 16:01:33 +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:In-Reply-To:MIME-Version:References: 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=H3iAbQOi2XzNTkNZb91Zgy1KY4NtIxC01KMAhatqUT4=; b=E9kVp/ETCqRj5Q SwsYDuEgk8c6Cqez6oaroMVKFVtS1rfhq2V+Rs5kMhT4nu2ShGDnvdUFz6nhXKI3ktH3QoKoSCGNs Vj1e8cR6Kr79eD5oA/sd87VwJQyjCLfVQe5xNtHCCBrR5Hv104IYeNq8SgIMnpw22njNZU+seSSzF lnRQatKUqlDyX6BjLzM5UxK4VccK0kxyruA+WqDVHepalEpQBvxS/HMp9ZmOMavQGaanrilRqFZJv iIiw7AzMADD13QcL87ksWj8Wybp9Gc3gLb9x+sXwQT+08BtpKMtimM5YC8f1yDMwEMLHrH39t5bfC ZgnItqa6cpb2AvYmXqVw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nMXZz-00ATrW-Oq; Tue, 22 Feb 2022 15:59:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nMXV5-00ARKQ-NG for linux-arm-kernel@lists.infradead.org; Tue, 22 Feb 2022 15:54:54 +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 8C48B1063; Tue, 22 Feb 2022 07:54:48 -0800 (PST) Received: from lakrids (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3AFD13F70D; Tue, 22 Feb 2022 07:54:47 -0800 (PST) Date: Tue, 22 Feb 2022 15:54:44 +0000 From: Mark Rutland To: Chengming Zhou Cc: rostedt@goodmis.org, mingo@redhat.com, catalin.marinas@arm.com, will@kernel.org, broonie@kernel.org, songmuchun@bytedance.com, qirui.001@bytedance.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64/ftrace: Make function graph use ftrace directly Message-ID: References: <20220222130049.81284-1-zhouchengming@bytedance.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220222130049.81284-1-zhouchengming@bytedance.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220222_075451_943381_5967B341 X-CRM114-Status: GOOD ( 29.91 ) 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 Tue, Feb 22, 2022 at 09:00:49PM +0800, Chengming Zhou wrote: > As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph > use ftrace directly"), we don't need special hook for graph tracer, > but instead we use graph_ops:func function to install return_hooker. > > Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add > implementation for FTRACE_WITH_REGS on arm64, we can easily adopt > the same optimization on arm64. This is a nice cleanup/refactoring, but I don't think this is an optimization as such; we're still doing the same work, just in marginally different place. So I'd suggest s/optimization/cleanup/ here. It's probably worth noting that this *only* changes the FTRACE_WITH_REGS implementation, and the mcount-based implementation is unaffected by this patch. > Signed-off-by: Chengming Zhou > --- > arch/arm64/include/asm/ftrace.h | 7 +++++++ > arch/arm64/kernel/entry-ftrace.S | 6 ------ > arch/arm64/kernel/ftrace.c | 21 +++++++++++++++++++++ > 3 files changed, 28 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h > index 1494cfa8639b..dbc45a4157fa 100644 > --- a/arch/arm64/include/asm/ftrace.h > +++ b/arch/arm64/include/asm/ftrace.h > @@ -80,8 +80,15 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > struct dyn_ftrace; > +struct ftrace_ops; > +struct ftrace_regs; > + > int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); > #define ftrace_init_nop ftrace_init_nop > + > +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > + struct ftrace_ops *op, struct ftrace_regs *fregs); > +#define ftrace_graph_func ftrace_graph_func > #endif > > #define ftrace_return_address(n) return_address(n) > diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S > index e535480a4069..eb4a69b1f84d 100644 > --- a/arch/arm64/kernel/entry-ftrace.S > +++ b/arch/arm64/kernel/entry-ftrace.S > @@ -97,12 +97,6 @@ SYM_CODE_START(ftrace_common) > SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) > bl ftrace_stub > > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER > -SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller(); > - nop // If enabled, this will be replaced > - // "b ftrace_graph_caller" > -#endif > - You should also be able to delete the FTRACE_WITH_REGS implementation of ftrace_graph_caller since that's now unused. Having that in the diff would also make it easier to compare to the logic in ftrace_graph_func(). > /* > * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved > * x19-x29 per the AAPCS, and we created frame records upon entry, so we need > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index 4506c4a90ac1..1b5da231b1de 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -268,6 +268,26 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, > } > > #ifdef CONFIG_DYNAMIC_FTRACE > +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +int ftrace_enable_ftrace_graph_caller(void) > +{ > + return 0; > +} > + > +int ftrace_disable_ftrace_graph_caller(void) > +{ > + return 0; > +} It's a shame the core code doesn't provide this if we provide an implementation of ftrace_graph_func. > + > +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > + struct ftrace_ops *op, struct ftrace_regs *fregs) > +{ > + struct pt_regs *regs = arch_ftrace_get_regs(fregs); > + unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs); > + > + prepare_ftrace_return(ip, parent, frame_pointer(regs)); > +} Other than my comments above, this looks about right, but I'd like to give this some testing before I give any tags. Could you respin this with the FTRACE_WITH_REGS ftrace_graph_caller asm removed? Thanks, Mark. > +#else > /* > * Turn on/off the call to ftrace_graph_caller() in ftrace_caller() > * depending on @enable. > @@ -297,5 +317,6 @@ int ftrace_disable_ftrace_graph_caller(void) > { > return ftrace_modify_graph_caller(false); > } > +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > #endif /* CONFIG_DYNAMIC_FTRACE */ > #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ > -- > 2.20.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel