From patchwork Fri Oct 18 17:36:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 13842109 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 591482076DF; Fri, 18 Oct 2024 17:37:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729273074; cv=none; b=jj1SoTGeL0qC69mi/3jLqvs0rJffDD+wCFyokTNnvGqaapSxT5M00BBE/Zb045s5fT6YWx/bwK6ltiMitqHyaQZAdEDexv8M0jycdig22d0RQ/mQJkYioO/WvggMMPDSNTiftbRPzqp0G74HvGgJaO7ROQwSRnBWUB/G8Df3/90= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729273074; c=relaxed/simple; bh=mzQaSKiFIvV1Ou/1SmtfbzngqaZMGo7HvE5vORtP2b8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nA8SrhBHzv9nVgcq1n32B6qAdhdem801DK8z0jO/x6IcT/b18/+2SYX6vdJ4+PjyUA7oU0OlSuPBnfQedishwZ+kIhGppYASfXN+5vOaXWGyl4I454FgtewlO7geijTlxsdHLznjTNSKk3hZ3WESBKWrsgz6DbuxZUdybienO6w= 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=L6Xfqctd; arc=none smtp.client-ip=148.163.158.5 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="L6Xfqctd" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 49ICZmv1023701; Fri, 18 Oct 2024 17:37:28 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=JGYWfrPfzXzPdrdn1 nMdFcY4hYimZxb7JncZtcrP9U4=; b=L6XfqctdAdQTQ5X3FHgkOm4NWoENrXw8u 7kCWChAL5LHLeNoz+IeJCjlLoYNLsLgdMU6Ex4J4eR0M1Z6K4YFT7EFziLuxx1vu P3HDlxgwwJVlqFbOufrgMO2ebNgYMtIdzhGh/J1LNlv/7w8XSa+UHZTlh0ybQCpR wzrsKk73suHj4GKR/4qLEvEuRQ95/3kbwRDS0pOvCRHgUd8+eH2t8/jF31ct2sZj TZS9I1sGSo/OIlD0/XQidXxIBP5/n1YUyuv+2+BOrc4VDEWCvu2DwTVBmUuBKZZs zaPRDhyvuHLKLnB9SbnX/EI0dnn+XYyBvMogz9K3jvoFdyvU4/j3w== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 42ar0ua92d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Oct 2024 17:37:27 +0000 (GMT) Received: from m0360072.ppops.net (m0360072.ppops.net [127.0.0.1]) by pps.reinject (8.18.0.8/8.18.0.8) with ESMTP id 49IHbRgl019214; Fri, 18 Oct 2024 17:37:27 GMT Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 42ar0ua927-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Oct 2024 17:37:27 +0000 (GMT) Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 49IHMVgR001982; Fri, 18 Oct 2024 17:37:26 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4284en600t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Oct 2024 17:37:26 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 49IHbM1852691360 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 18 Oct 2024 17:37:22 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5ACE820040; Fri, 18 Oct 2024 17:37:22 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5159620043; Fri, 18 Oct 2024 17:37:18 +0000 (GMT) Received: from li-bd3f974c-2712-11b2-a85c-df1cec4d728e.ibm.com.com (unknown [9.43.99.188]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 18 Oct 2024 17:37:18 +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: Michael Ellerman , "Naveen N. Rao" , Mark Rutland , Daniel Borkmann , Masahiro Yamada , Nicholas Piggin , Alexei Starovoitov , Steven Rostedt , Masami Hiramatsu , Andrii Nakryiko , Christophe Leroy , Vishal Chourasia , Mahesh J Salgaonkar Subject: [PATCH v6 10/17] powerpc/ftrace: Add a postlink script to validate function tracer Date: Fri, 18 Oct 2024 23:06:25 +0530 Message-ID: <20241018173632.277333-11-hbathini@linux.ibm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241018173632.277333-1-hbathini@linux.ibm.com> References: <20241018173632.277333-1-hbathini@linux.ibm.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: rbcGewJQCxkyPEldCazRbreCxL64LPWi X-Proofpoint-ORIG-GUID: wFfpNO7IdFXcKyC-6o_aqKlHsqbWKkfj X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxscore=0 spamscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 phishscore=0 suspectscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2410180111 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 Signed-off-by: Hari Bathini --- Changes in v6: * Shellcheck warnings fixed for arch/powerpc/tools/ftrace_check.sh 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 8094a01974cc..bd1ca813e71c 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 + $(call cmd,ftrace_check) +endif +endif clean: rm -f .tmp_symbols.txt diff --git a/arch/powerpc/tools/ftrace_check.sh b/arch/powerpc/tools/ftrace_check.sh new file mode 100755 index 000000000000..405e7e306617 --- /dev/null +++ b/arch/powerpc/tools/ftrace_check.sh @@ -0,0 +1,50 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later +# +# This script checks vmlinux to ensure that all functions can call ftrace_caller() either directly, +# or through the stub, ftrace_tramp_text, at the end of kernel text. + +# Error out if any command fails +set -e + +# Allow for verbose output +if [ "$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