From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39B3D2EA729 for ; Mon, 20 Oct 2025 08:19:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760948377; cv=none; b=A6VMq/0CNCyoMVaPwiXPXEIvStC1xIw5HaMiAWS96KSSvVt9TO0ZH8bneWeE2fVeHm19racxMLVVhrWMGfdGvgiBK501S/0v9j256B8CvSCimifoAxbaXEQatJ+RnFssyCbzlqPX8mdolyhwVXvU5enJDPNccLFElI/JtPH8Q0Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760948377; c=relaxed/simple; bh=dRWXfEC0xTJRSDH0laop22EviOdJHMRGgqbpL7o/Nfc=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fOtleo9GOkbkrnZijM8Oxjlewy/YyR/Mh2lHyIcND4iSSkuUrvnE9K6D80UkdmZOTA+t5hP9ZUPYqP/H1yvpIUnW+BIyMWlxXQjRCfdN+nZVCBTvcslyPKGb1UEwZSSbipwdTj7cgkvHxQ5PqR17C1jSlQhcTqJZAQtYQnmQbMU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ncnia1ej; arc=none smtp.client-ip=209.85.128.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ncnia1ej" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-471076f819bso32143025e9.3 for ; Mon, 20 Oct 2025 01:19:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760948374; x=1761553174; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=wu1seAuHBCMknQQxCUTYBtZscbydnbBYQKqotBsvZIk=; b=ncnia1ejP8CJJlHdtfI/TT9LG5Wxh+GyY4WDjy8NqaExtircZKxajf8NEDSiNHtwSz +RTQv9hpLYoDjU6I3escnVZtMUw1NN8XTf5UhmEfBWA9izADPd98o+lxNKp4LlIM9SZl ODIMoTdzIWS85LXkyEaIhHhzb/AttEFTt3osrqwgZCsEt028lNemtwqBof97eGrfn/0H JpzGbFSK5UXJ0NNyeR3nCiht5uY1JKvxN1CVIGbyIiP0NbjxIVb2A499eUD5zA9MHriD qZXzB15huGp1m8cNQToBS6l8v4PwzCY2IfxGH/J0aHNxW7poxhx6YFvVlAB0LzhMj3km s9Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760948374; x=1761553174; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=wu1seAuHBCMknQQxCUTYBtZscbydnbBYQKqotBsvZIk=; b=uIMgFS5+Anj2K4M/FfGfFQlReAoXQPZUYqJlkXCck2g4wVq8KnwPfQcCt5G63rPXYZ REzrQiu0SepSUVu0HTRVMzK5hQVZgAxT+58W4ZYhOmo/UKqmV/68h+v9e7a7fZ5havTt NRNqd/dxe4rNTHRwvFx2+RZii3iDX0yh1FlrEd+LxL49gJ/b6bs4F+YxrtX7qOeEIm8M ND8Lfay8v0ZLzpsc+coUYPVwiigSpZrR+3wHvQHMfgVvw5hPnwo0VI43COOxHhoO4ksH 8Scq403zlBVTNesPUgSdOuJ/wvAZ8c/QH2lRcAb1dewMFw5kZK59XOpetPYlWT/vUjJ3 NuRw== X-Forwarded-Encrypted: i=1; AJvYcCVpZloNz8BJuVTn2jKQXRUR+hnGE0B3+UD0aoANrfn884s6dFo6hoXu8vu/10vfJ3XsRYihKvRoTUMM3C1MkgcX7Gk=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+bT5CBQ6NdCClDgA6MxAlET5564NNV2Xv4r8Pxge30FRd6Pvn MtcKFHTY95IAT9nveYrPXJ7cRsPRypw8ZM3mjmH/2Nq/FvxJ3JzR9542 X-Gm-Gg: ASbGncvWh4KRZN7y/DDjm+9B/huunP/P2C4UePGxGVh+RaCqWmE+CYSgGtsbYWtJPL9 vME6A8+TnLKuFgoMOppWKG/AcO3VkbN4+vpJAFPr5zQ0WrPsfFvWgws4lvRkMaXPYWXck8d25VQ 1ElxY7MYM0YSRGQyBBXZN9RDwxBttGeaQ5BC0fPKNr3QtTnI3SJLoaHCQ4ja1sukGQ6UEV48x4l fQ5pOcRkrVIL6YJS4n88tqjK0byzbULaDONj5qNxqjmECSVBkKFlHL0em2fns5+l0IYONRbdoSc WENhgEmhsIYBB/F4NOJTa7W0XMxdsKmtSgqKo+wmIh+qUWcaj5JTLKzL2igc5C65MrbVvrLQa9r 4oEMjsoNabDtpQwSwx/ekr+hXxZMVPtfe5G3qtzlEQHBXJhsL0g== X-Google-Smtp-Source: AGHT+IGo1h4skDOY0gnPLoWISFUW5QAgaJqv6OnKZUGGuJuaXpCB4f6qGyZgMzr2CQkmgdVZ+Q6xMQ== X-Received: by 2002:a05:600c:674a:b0:46f:b327:31c5 with SMTP id 5b1f17b1804b1-471177ba398mr87335545e9.0.1760948374422; Mon, 20 Oct 2025 01:19:34 -0700 (PDT) Received: from krava ([2a02:8308:a00c:e200::31e0]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-427f00ce3e2sm14060552f8f.47.2025.10.20.01.19.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Oct 2025 01:19:34 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Mon, 20 Oct 2025 10:19:32 +0200 To: Menglong Dong Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, mattbobrowski@google.com, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, leon.hwang@linux.dev, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH RFC bpf-next 3/5] bpf,x86: add tracing session supporting for x86_64 Message-ID: References: <20251018142124.783206-1-dongml2@chinatelecom.cn> <20251018142124.783206-4-dongml2@chinatelecom.cn> 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-Disposition: inline In-Reply-To: <20251018142124.783206-4-dongml2@chinatelecom.cn> On Sat, Oct 18, 2025 at 10:21:22PM +0800, Menglong Dong wrote: SNIP > /* mov rax, qword ptr [rbp - rounded_stack_depth - 8] */ > #define LOAD_TRAMP_TAIL_CALL_CNT_PTR(stack) \ > __LOAD_TCC_PTR(-round_up(stack, 8) - 8) > @@ -3179,8 +3270,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im > void *func_addr) > { > int i, ret, nr_regs = m->nr_args, stack_size = 0; > - int regs_off, nregs_off, ip_off, run_ctx_off, arg_stack_off, rbx_off; > + int regs_off, nregs_off, session_off, ip_off, run_ctx_off, > + arg_stack_off, rbx_off; > struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; > + struct bpf_tramp_links *session = &tlinks[BPF_TRAMP_SESSION]; > struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; > struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; > void *orig_call = func_addr; > @@ -3222,6 +3315,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im > * > * RBP - nregs_off [ regs count ] always > * > + * RBP - session_off [ session flags ] tracing session > + * > * RBP - ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag > * > * RBP - rbx_off [ rbx value ] always > @@ -3246,6 +3341,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im > /* regs count */ > stack_size += 8; > nregs_off = stack_size; > + stack_size += 8; > + session_off = stack_size; should this depend on session->nr_links ? jirka > > if (flags & BPF_TRAMP_F_IP_ARG) > stack_size += 8; /* room for IP address argument */ > @@ -3345,6 +3442,13 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im > return -EINVAL; > } > > + if (session->nr_links) { > + if (invoke_bpf_session_entry(m, &prog, session, regs_off, > + run_ctx_off, session_off, > + image, rw_image)) > + return -EINVAL; > + } > + > if (fmod_ret->nr_links) { > branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *), > GFP_KERNEL); > @@ -3409,6 +3513,15 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im > } > } > > + if (session->nr_links) { > + if (invoke_bpf_session_exit(m, &prog, session, regs_off, > + run_ctx_off, session_off, > + image, rw_image)) { > + ret = -EINVAL; > + goto cleanup; > + } > + } > + > if (flags & BPF_TRAMP_F_RESTORE_REGS) > restore_regs(m, &prog, regs_off); > > -- > 2.51.0 >