From patchwork Sun Sep 15 20:56:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 13804959 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 E05737A15A; Sun, 15 Sep 2024 20:58:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726433885; cv=none; b=e76L3apogLIuGlFW3bOqh5iWoBzmsu7kmfJEeJnKqb/j/Y5EU/IjFViBKEfmo+rpIlmUtuqAsVytQN940FjXiDgP0xnVt1HS4mu40SNS8WV/GlOtoITlwr3EAbyuiwi9yI0NYwbZFgp+wZoibp7AJzW48ztKMTfuUrJtGgIaHSo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726433885; c=relaxed/simple; bh=naOabv/u4ELoz9PvxINelPShW0wR0eKSvYEcD+kfboE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RmYY6+AcC0qzFn9iEik5zmgz/l9PsQDQvNVJoHJqcLOeUM9rRhnG6jGwsw4+jB+sSeNOwfPyRDW2EakjXuwZxJO1cM3VFOe+SDl5nuHiT7sA2cio0QR4y07y4Xbsd1SDuvTgHxlKkHeZdIByx7BR49aGC/QfW/C+tu1xrTTYVuI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=cbwNXHG3; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="cbwNXHG3" Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 48FKmcfB000823; Sun, 15 Sep 2024 20:57:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from :to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=pp1; bh=AxsJpLHo8dECO zs4gUkT1Yc+imfdAslCddi/zcVEccY=; b=cbwNXHG3VsQovSVT8iwdGR5jLwUEX 5D0Kc5u64rL7NZUhuSGf86x2DFczE9Wr5XtKH3btkGtNGKsxVP8seu62WqsFPDSx F3nlPkeHp0YqAHN3CSslGrk4gags+6N4VHemKBgZ1wqNe0nD95/Ey/Mygc8kIzsg 2f8R2niQ9yH0Un6GB+2qOcuXl/OSCB7RdVTxy1GbHZ+e9M/zmKfAazuyncXP1N+a Lf0KYNfkCiON76wbPtQJgqQeOQkJcPOzABz9+rmJuZYE7+wRp6cwfoEBwLfsw94y Iyxy33a7oskVqhGBI/4WxKGrQmqYe15B8gL9G5pITixAV/pogt8AoogXQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 41n3ucxerc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:41 +0000 (GMT) Received: from m0360083.ppops.net (m0360083.ppops.net [127.0.0.1]) by pps.reinject (8.18.0.8/8.18.0.8) with ESMTP id 48FKveXD015811; Sun, 15 Sep 2024 20:57:40 GMT Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 41n3ucxera-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:40 +0000 (GMT) Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 48FHCX6e001871; Sun, 15 Sep 2024 20:57:39 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 41nqh3bc0e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:39 +0000 Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay01.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 48FKva3r55443764 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 15 Sep 2024 20:57:36 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 09C6620049; Sun, 15 Sep 2024 20:57:36 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A332120040; Sun, 15 Sep 2024 20:57:32 +0000 (GMT) Received: from li-bd3f974c-2712-11b2-a85c-df1cec4d728e.ibm.com.com (unknown [9.43.68.55]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Sun, 15 Sep 2024 20:57:32 +0000 (GMT) From: Hari Bathini To: linuxppc-dev , bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Naveen N. Rao" , Mark Rutland , Daniel Borkmann , Masahiro Yamada , Nicholas Piggin , Alexei Starovoitov , Steven Rostedt , Andrii Nakryiko , Christophe Leroy , Vishal Chourasia , Mahesh J Salgaonkar , Masami Hiramatsu Subject: [PATCH v5 10/17] powerpc/ftrace: Add a postlink script to validate function tracer Date: Mon, 16 Sep 2024 02:26:41 +0530 Message-ID: <20240915205648.830121-11-hbathini@linux.ibm.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240915205648.830121-1-hbathini@linux.ibm.com> References: <20240915205648.830121-1-hbathini@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 0kGxEAevJzIpxHJsWu9dk5-6WLrJnEbo X-Proofpoint-ORIG-GUID: 1rTmZJ8O7kfiC1XaFKXsp6vOPrMqkH7l X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-15_12,2024-09-13_02,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 phishscore=0 impostorscore=0 spamscore=0 priorityscore=1501 suspectscore=0 adultscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2408220000 definitions=main-2409150159 From: Naveen N Rao Function tracer on powerpc can only work with vmlinux having a .text size of up to ~64MB due to powerpc branch instruction having a limited relative branch range of 32MB. Today, this is only detected on kernel boot when ftrace is init'ed. Add a post-link script to check the size of .text so that we can detect this at build time, and break the build if necessary. We add a dependency on !COMPILE_TEST for CONFIG_HAVE_FUNCTION_TRACER so that allyesconfig and other test builds can continue to work without enabling ftrace. Signed-off-by: Naveen N Rao --- arch/powerpc/Kconfig | 2 +- arch/powerpc/Makefile.postlink | 8 +++++ arch/powerpc/tools/ftrace_check.sh | 50 ++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+), 1 deletion(-) create mode 100755 arch/powerpc/tools/ftrace_check.sh diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 1f9d23b276b5..de18f3baff66 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -243,7 +243,7 @@ config PPC select HAVE_FUNCTION_DESCRIPTORS if PPC64_ELF_ABI_V1 select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUNCTION_GRAPH_TRACER - select HAVE_FUNCTION_TRACER if PPC64 || (PPC32 && CC_IS_GCC) + select HAVE_FUNCTION_TRACER if !COMPILE_TEST && (PPC64 || (PPC32 && CC_IS_GCC)) select HAVE_GCC_PLUGINS if GCC_VERSION >= 50200 # plugin support on gcc <= 5.1 is buggy on PPC select HAVE_GENERIC_VDSO select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC_BOOK3S_64 && SMP diff --git a/arch/powerpc/Makefile.postlink b/arch/powerpc/Makefile.postlink index ae5a4256b03d..bb601be36173 100644 --- a/arch/powerpc/Makefile.postlink +++ b/arch/powerpc/Makefile.postlink @@ -24,6 +24,9 @@ else $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/relocs_check.sh "$(OBJDUMP)" "$(NM)" "$@" endif +quiet_cmd_ftrace_check = CHKFTRC $@ + cmd_ftrace_check = $(CONFIG_SHELL) $(srctree)/arch/powerpc/tools/ftrace_check.sh "$(NM)" "$@" + # `@true` prevents complaint when there is nothing to be done vmlinux: FORCE @@ -34,6 +37,11 @@ endif ifdef CONFIG_RELOCATABLE $(call if_changed,relocs_check) endif +ifdef CONFIG_FUNCTION_TRACER +ifndef CONFIG_PPC64_ELF_ABI_V1 + $(call cmd,ftrace_check) +endif +endif clean: rm -f .tmp_symbols.txt diff --git a/arch/powerpc/tools/ftrace_check.sh b/arch/powerpc/tools/ftrace_check.sh new file mode 100755 index 000000000000..f4310e736f1b --- /dev/null +++ b/arch/powerpc/tools/ftrace_check.sh @@ -0,0 +1,50 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later +# +# This script checks vmlinux to ensure that all functions can call ftrace_caller() either directly, +# or through the stub, ftrace_tramp_text, at the end of kernel text. + +# Error out if any command fails +set -e + +# Allow for verbose output +if [ "$V" = "1" ]; then + set -x +fi + +if [ $# -lt 2 ]; then + echo "$0 [path to nm] [path to vmlinux]" 1>&2 + exit 1 +fi + +# Have Kbuild supply the path to nm so we handle cross compilation. +nm="$1" +vmlinux="$2" + +stext_addr=$($nm "$vmlinux" | grep -e " [TA] _stext$" | \ + cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') +ftrace_caller_addr=$($nm "$vmlinux" | grep -e " T ftrace_caller$" | \ + cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') +ftrace_tramp_addr=$($nm "$vmlinux" | grep -e " T ftrace_tramp_text$" | \ + cut -d' ' -f1 | tr '[[:lower:]]' '[[:upper:]]') + +ftrace_caller_offset=$(echo "ibase=16;$ftrace_caller_addr - $stext_addr" | bc) +ftrace_tramp_offset=$(echo "ibase=16;$ftrace_tramp_addr - $ftrace_caller_addr" | bc) +sz_32m=$(printf "%d" 0x2000000) +sz_64m=$(printf "%d" 0x4000000) + +# ftrace_caller - _stext < 32M +if [ $ftrace_caller_offset -ge $sz_32m ]; then + echo "ERROR: ftrace_caller (0x$ftrace_caller_addr) is beyond 32MiB of _stext" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \ + of kernel text" 1>&2 + exit 1 +fi + +# ftrace_tramp_text - ftrace_caller < 64M +if [ $ftrace_tramp_offset -ge $sz_64m ]; then + echo "ERROR: kernel text extends beyond 64MiB from ftrace_caller" 1>&2 + echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \ + of kernel text" 1>&2 + exit 1 +fi