From patchwork Sun Sep 15 20:56:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 13804932 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 3543545023; Sun, 15 Sep 2024 20:57:29 +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=1726433852; cv=none; b=kG4ImfIGD8/T1zpzJn/aY08HAVxphTb4/vQiEDfbltsN82vU5YZTj/83O6OOpooST0FlWsmk8cIkL/f0eeW0EufskVQeoxwS3LEPw4GiMATqTpLlFoeVd++NfcNTeLmim/bwK5yylr0iXNxTfebBKzlrylFKMk1DPOqp/KzekmQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726433852; c=relaxed/simple; bh=zA/QsWa6q7LJTtE5ublcb3HICHudBVDInko7cvOFggU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YEb0WhrZMzVXdWhQYninvrl8G/wrzQRlnTJzDo8rNaRN7KUFwy1+jQQw91FubOOxUXlmxc3XMHLyC1iuPE+FPpSjbSVQedZfEzRXyAe8CYKiTuwj+tNADZA+/SFgy2aCAxqyQLylhZ/SDESG7+7fbNyHHbEbFQjX6K8iyeZ+RKM= 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=bmVAqrCu; 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="bmVAqrCu" 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 48FKmRuF026980; Sun, 15 Sep 2024 20:57:07 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=zQA7iLTfCFqW2 Uv7PmpE+IQDhTe/2DO2+wb/qAwSldk=; b=bmVAqrCungPA2O+pwXvERYAqffgdS 7uz1oR3/7y7a0aIxyUJAOHvuQ4AlNmei3FEhdFlPLOv2QmHmTGa2qngYDHPn5ga3 vIGje88C9N+Cxm6V+TarHdXC1jDKAIn54pbdUt69DuC0QUBqmWbYl2zzfFevw9+f i0Uj4AFYFaEcCu6V8MJ8ZEfmAy/0CCxOccISrzAhtwls3hTlAx29XgByg1d925AK vdkq8lYgt2eq4+79seEYf/cIy2DBU1e9PSviB5YTEXtcs9fY9e/eGMwYQDNNzq2D 1L4OQ18nzbX/uS9gy3gByDc01N50uYEQaFNuJgWBD4AMJ0n1cCYxQiRFg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 41n41a682u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:06 +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 48FKv616010815; Sun, 15 Sep 2024 20:57:06 GMT Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 41n41a682r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:06 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 48FI3QWW001960; Sun, 15 Sep 2024 20:57:05 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 41nmtubyc5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 15 Sep 2024 20:57:05 +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 48FKv1BN54657404 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 15 Sep 2024 20:57:02 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D660020049; Sun, 15 Sep 2024 20:57:01 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F061520040; Sun, 15 Sep 2024 20:56:57 +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 20:56:57 +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 02/17] powerpc/kprobes: Use ftrace to determine if a probe is at function entry Date: Mon, 16 Sep 2024 02:26:33 +0530 Message-ID: <20240915205648.830121-3-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-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: eyE_Tdvn-PAycfH2ToAXay_fjHRPGcBM X-Proofpoint-ORIG-GUID: EnC10AeeZviH-DJ3W2DqeDRShj48SZLI 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 adultscore=0 lowpriorityscore=0 suspectscore=0 mlxscore=0 mlxlogscore=999 bulkscore=0 impostorscore=0 phishscore=0 priorityscore=1501 spamscore=0 clxscore=1015 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2408220000 definitions=main-2409150159 From: Naveen N Rao Rather than hard-coding the offset into a function to be used to determine if a kprobe is at function entry, use ftrace_location() to determine the ftrace location within the function and categorize all instructions till that offset to be function entry. For functions that cannot be traced, we fall back to using a fixed offset of 8 (two instructions) to categorize a probe as being at function entry for 64-bit elfv2, unless we are using pcrel. Acked-by: Masami Hiramatsu (Google) Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/kprobes.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index f8aa91bc3b17..bf382c459e1f 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -105,24 +105,22 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) return addr; } -static bool arch_kprobe_on_func_entry(unsigned long offset) +static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset) { -#ifdef CONFIG_PPC64_ELF_ABI_V2 -#ifdef CONFIG_KPROBES_ON_FTRACE - return offset <= 16; -#else - return offset <= 8; -#endif -#else + unsigned long ip = ftrace_location(addr); + + if (ip) + return offset <= (ip - addr); + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return offset <= 8; return !offset; -#endif } /* XXX try and fold the magic of kprobe_lookup_name() in this */ kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry) { - *on_func_entry = arch_kprobe_on_func_entry(offset); + *on_func_entry = arch_kprobe_on_func_entry(addr, offset); return (kprobe_opcode_t *)(addr + offset); }