From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 17F9721E3CA; Tue, 15 Oct 2024 23:33:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729035203; cv=none; b=MsaREQzTMa33wCQgMvfjrov5c3dhVHJKVqDrLAoALAfX9H8k2TXYBamIWNxqa/1wGQl5YoTkysX71eEUckc3d8O9juBmXKLs+OT/qbQmQ3Q6XvEdWBMVTR3HDJJf3dIMPzIPX0jBfVU8MwR7l1SOjLusXBDsnELiU0I+7sCg0tk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729035203; c=relaxed/simple; bh=pb1LrK5LVSejDLEENkQ1SqMi84EwNgD9qtouXy5b7Z8=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=OOHko+hIZUQdLdhLaP9VvZOdGs1+J8NAwIbd9UlX5CVD4xYStZF5PEmOVUOIDwV1SzmbembTCkkehDtBmRhL+KnqgykViO7oqhU7wc7tDvpwfdvfCuVpiINTFtMO6p0+Y0SQTprozb/Ve2Qi6efe+tGbXd4m5k4Fj8gHNFe/WAs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q2cTIaN5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q2cTIaN5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06A05C4CEC6; Tue, 15 Oct 2024 23:33:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729035202; bh=pb1LrK5LVSejDLEENkQ1SqMi84EwNgD9qtouXy5b7Z8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q2cTIaN5ot66UVgfOzGaLyp44X6PuFb8ClxeeqwsNp9SIs6DrmnhTxw86R+Rbdfgz sJ7OzE1zlMdkkJaPc6LQBwbT8/5tGO8QX0GdBl53+F5+kdZXkQ79Sq4OitGQXLfWTu H+wenRZT+6OzUV/ZWC5fUUuzUcO9CeY9aBL8ryPMF0Aw7nWdaW06Vb7qFXa8DEunwq PD1ytlBNZQZBjkZL4BVCpSyA11V8jY6M7egVYgdEJrYvHxo6pwESHwi6vIqmtXGJo7 HkGoERfpzVK31kJ1uuHvz1fB4q/nGrozvAt2qmDJ4IxjTTpHchITbpxMrit2q5Rvvr A09EPGFluXpgg== Date: Wed, 16 Oct 2024 08:33:13 +0900 From: Masami Hiramatsu (Google) To: Heiko Carstens Cc: Alexei Starovoitov , Steven Rostedt , Florent Revest , linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Alexei Starovoitov , Jiri Olsa , Alan Maguire , Mark Rutland , linux-arch@vger.kernel.org, Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Paul Walmsley , Palmer Dabbelt , Albert Ou , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Mathieu Desnoyers Subject: Re: [PATCH v16 04/18] function_graph: Replace fgraph_ret_regs with ftrace_regs Message-Id: <20241016083313.7198a3abf87e45ddb3dbb671@kernel.org> In-Reply-To: <20241015183906.19678-B-hca@linux.ibm.com> References: <172895571278.107311.14000164546881236558.stgit@devnote2> <172895575716.107311.6784997045170009035.stgit@devnote2> <20241015183906.19678-B-hca@linux.ibm.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 15 Oct 2024 20:39:06 +0200 Heiko Carstens wrote: > On Tue, Oct 15, 2024 at 10:29:17AM +0900, Masami Hiramatsu (Google) wrote: > > From: Masami Hiramatsu (Google) > > > > Use ftrace_regs instead of fgraph_ret_regs for tracing return value > > on function_graph tracer because of simplifying the callback interface. > > > > The CONFIG_HAVE_FUNCTION_GRAPH_RETVAL is also replaced by > > CONFIG_HAVE_FUNCTION_GRAPH_FREGS. > > > > Signed-off-by: Masami Hiramatsu (Google) > > ... > > > diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S > > index 7e267ef63a7f..a9ca56ea0858 100644 > > --- a/arch/s390/kernel/mcount.S > > +++ b/arch/s390/kernel/mcount.S > > @@ -134,14 +134,15 @@ SYM_CODE_END(ftrace_common) > > SYM_FUNC_START(return_to_handler) > > stmg %r2,%r5,32(%r15) > > lgr %r1,%r15 > > - aghi %r15,-(STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE) > > + aghi %r15,-(STACK_FRAME_OVERHEAD+STACK_FRAME_SIZE_FREGS) > > stg %r1,__SF_BACKCHAIN(%r15) > > - la %r3,STACK_FRAME_OVERHEAD(%r15) > > - stg %r1,__FGRAPH_RET_FP(%r3) > > - stg %r2,__FGRAPH_RET_GPR2(%r3) > > - lgr %r2,%r3 > > + la %r4,STACK_FRAME_OVERHEAD(%r15) > > + stg %r2,__PT_R2(%r4) > > + stg %r3,__PT_R3(%r4) > > + stg %r1,__PT_R15(%r4) > > + lgr %r2,%r4 > > brasl %r14,ftrace_return_to_handler > > - aghi %r15,STACK_FRAME_OVERHEAD+__FGRAPH_RET_SIZE > > + aghi %r15,STACK_FRAME_SIZE_FREGS > > lgr %r14,%r2 > > lmg %r2,%r5,32(%r15) > > BR_EX %r14 > > Why didn't you simply merge the addon patch which I provided, and > which I tested? > https://lore.kernel.org/all/20240916121656.20933-B-hca@linux.ibm.com > > That would make things much simpler... e.g. your new patch is also > writing r3 to fregs, why? The stackframe allocation is also wrong. > I didn't try, but I guess the above code would crash instantly. I thought it is better to focus on replacing fgraph_ret_regs with ftrace_regs in this patch, but if it is wrong and I should remove stack_frame, let me fix that. Thank you, -- Masami Hiramatsu (Google)