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Wed, 04 Sep 2024 06:59:21 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 4846xJVk53346580 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 4 Sep 2024 06:59:19 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7160E20043; Wed, 4 Sep 2024 06:59:19 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5F76D20040; Wed, 4 Sep 2024 06:59:19 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 4 Sep 2024 06:59:19 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 55390) id 203CEE0297; Wed, 4 Sep 2024 08:59:19 +0200 (CEST) From: Sven Schnelle To: Steven Rostedt , Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH 4/7] Add print_function_args() Date: Wed, 4 Sep 2024 08:58:58 +0200 Message-ID: <20240904065908.1009086-5-svens@linux.ibm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240904065908.1009086-1-svens@linux.ibm.com> References: <20240904065908.1009086-1-svens@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: g7qxufGOAcbGUCKmLgjBagyF508u6CrB X-Proofpoint-ORIG-GUID: g7qxufGOAcbGUCKmLgjBagyF508u6CrB 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=2024-09-04_04,2024-09-03_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 clxscore=1011 mlxscore=0 impostorscore=0 malwarescore=0 suspectscore=0 priorityscore=1501 adultscore=0 mlxlogscore=999 bulkscore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2407110000 definitions=main-2409040049 Add a function to decode argument types with the help of BTF. Will be used to display arguments in the function and function graph tracer. Signed-off-by: Sven Schnelle --- kernel/trace/trace_output.c | 68 +++++++++++++++++++++++++++++++++++++ kernel/trace/trace_output.h | 9 +++++ 2 files changed, 77 insertions(+) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index d8b302d01083..70405c4cceb6 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -12,8 +12,11 @@ #include #include #include +#include +#include #include "trace_output.h" +#include "trace_btf.h" /* must be a power of 2 */ #define EVENT_HASHSIZE 128 @@ -669,6 +672,71 @@ int trace_print_lat_context(struct trace_iterator *iter) return !trace_seq_has_overflowed(s); } +#ifdef CONFIG_FUNCTION_TRACE_ARGS +void print_function_args(struct trace_seq *s, struct ftrace_regs *fregs, + unsigned long func) +{ + const struct btf_param *param; + const struct btf_type *t; + const char *param_name; + char name[KSYM_NAME_LEN]; + unsigned long arg; + struct btf *btf; + s32 tid, nr = 0; + int i; + + trace_seq_printf(s, "("); + + if (!ftrace_regs_has_args(fregs)) + goto out; + if (lookup_symbol_name(func, name)) + goto out; + + btf = bpf_get_btf_vmlinux(); + if (IS_ERR_OR_NULL(btf)) + goto out; + + t = btf_find_func_proto(name, &btf); + if (IS_ERR_OR_NULL(t)) + goto out; + + param = btf_get_func_param(t, &nr); + if (!param) + goto out_put; + + for (i = 0; i < nr; i++) { + arg = ftrace_regs_get_argument(fregs, i); + + param_name = btf_name_by_offset(btf, param[i].name_off); + if (param_name) + trace_seq_printf(s, "%s = ", param_name); + t = btf_type_skip_modifiers(btf, param[i].type, &tid); + if (!t) + continue; + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_PTR: + trace_seq_printf(s, "0x%lx", arg); + break; + case BTF_KIND_INT: + trace_seq_printf(s, "%ld", arg); + break; + case BTF_KIND_ENUM: + trace_seq_printf(s, "%ld", arg); + break; + default: + trace_seq_printf(s, "0x%lx (%d)", arg, BTF_INFO_KIND(param[i].type)); + break; + } + if (i < nr - 1) + trace_seq_printf(s, ", "); + } +out_put: + btf_put(btf); +out: + trace_seq_printf(s, ")"); +} +#endif + /** * ftrace_find_event - find a registered event * @type: the type of event to look for diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index dca40f1f1da4..a21d8ce606f7 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -41,5 +41,14 @@ extern struct rw_semaphore trace_event_sem; #define SEQ_PUT_HEX_FIELD(s, x) \ trace_seq_putmem_hex(s, &(x), sizeof(x)) +#ifdef CONFIG_FUNCTION_TRACE_ARGS +void print_function_args(struct trace_seq *s, struct ftrace_regs *fregs, + unsigned long func); +#else +static inline void print_function_args(struct trace_seq *s, struct ftrace_regs *fregs, + unsigned long func) { + trace_seq_puts(s, "()"); +} +#endif #endif