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 B890DBA20; Wed, 11 Sep 2024 00:39:55 +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=1726015195; cv=none; b=Z2bhubXmCdJAYQb/W2sGZSztbJokjD3HCaO51ABhQLKJCsAw5mX5OaJGuzc70VEe5x8PqwHOCnmhIvWfX+8xMxUixiJNi4jqhuKOmubtt4mExFWQPTjXxUUhjaQGdY0/4RytgLuFQiWn1YmBay3vLHErkF8aXbLI3nh3BloLIOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726015195; c=relaxed/simple; bh=/fBDpPiu3lGHYDzGSOLr2nCGAJ0lbLinn72VPH8yw4U=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=AXik5JbeSqvMpmjqx6jhHTY1EbGcayrmBWspiC3JQDtcpl/5oBhqgRwXMRJo3yvyWtYdVMqucYGkBoseLVK2nI4sjSEdL2DoWHi5+oKEILMLAfbAeOcrlkn/QFtQuulPRk3b++eHs1PyorX9v9u6dYk6+/dcSJC0/RBWAKxTE1s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NDHN0VU1; 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="NDHN0VU1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BFBE4C4CEC3; Wed, 11 Sep 2024 00:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726015195; bh=/fBDpPiu3lGHYDzGSOLr2nCGAJ0lbLinn72VPH8yw4U=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NDHN0VU14VplbHJbatz0aF9iTnC0LJne7hqG/Os83afPXIv/xvjD7G7fqIy31pT1E MGq9Fyilb5XGLAeM+AlG8wjuD9s6KfmLwnqh3qhkGR5h7boQnt3+CeERiIDjwwDuDB 1ODWrwjxGxTpW8vAqKphnEuYaAXOGl98YZJ0OTkeuMPLutqojv/ZE7bldUXbefcASD 3yeaYSu41uhSTnngfAY6DNzoRZyQiGy1J8phr+B5Ld2b9F15vHcD3+yCzZ5tls1m/m 2hhqSjmSG9YMgkMbya6FmdFaCjt4dBXUEEQX/W/mTD0bP3vvzeu5mnao0XFI0+lE4y Q4bd/jxlBxnIw== Date: Wed, 11 Sep 2024 09:39:49 +0900 From: Masami Hiramatsu (Google) To: Andrii Nakryiko Cc: Steven Rostedt , Masami Hiramatsu , bpf , Linux trace kernel , adubey@linux.ibm.com, "Naveen N. Rao" , KP Singh , linux-arm-kernel , Mark Rutland , Will Deacon , Alexei Starovoitov , Catalin Marinas , Florent Revest , Puranjay Mohan Subject: Re: Unsupported CONFIG_FPROBE and CONFIG_RETHOOK on ARM64 Message-Id: <20240911093949.40e65804d0e517a1fa1cba11@kernel.org> In-Reply-To: References: <20240910145431.20e9d2e5@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: bpf@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, 10 Sep 2024 13:29:57 -0700 Andrii Nakryiko wrote: > You are probably talking about [0]. But I was asking about [1], i.e., > adding HAVE_RETHOOK support to ARM64. Despite all your emotions above, > can I still get a meaningful answer as for why that wasn't landed and > what prevents it from landing right now before Masami's 20-patch > series lands? As I replied to your last email, Mark discovered that [1] is incorrect. From the bpf perspective, it may be fine that struct pt_regs is missing some architecture-specific registers, but from an API perspective, it is a problem. Actually kretprobes on arm64 still does not do it correctly, but I also know most of users does not care. So currently I keep it as it is. But after fixing this issue on fprobe. I would like to update kretprobe so that it will use sw-breakpoint to handle it. It will increase the overhead of kretprobe, but it should be replaced by fprobe at that moment. Thank you, > > [0] https://lore.kernel.org/linux-trace-kernel/172398527264.293426.2050093948411376857.stgit@devnote2/ > [1] https://lore.kernel.org/bpf/164338038439.2429999.17564843625400931820.stgit@devnote2/ > > > > > Again, just letting you know. > > > > -- Steve -- Masami Hiramatsu (Google)