From patchwork Thu Dec 15 04:33:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linyu Yuan X-Patchwork-Id: 13073898 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DA69C00145 for ; Thu, 15 Dec 2022 04:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229549AbiLOEdr (ORCPT ); Wed, 14 Dec 2022 23:33:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229460AbiLOEdk (ORCPT ); Wed, 14 Dec 2022 23:33:40 -0500 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A10132A27A; Wed, 14 Dec 2022 20:33:39 -0800 (PST) Received: from pps.filterd (m0279870.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2BF2RZYR029046; 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Thu, 15 Dec 2022 04:33:34 GMT Received: from linyyuan-gv.qualcomm.com (10.80.80.8) by nalasex01b.na.qualcomm.com (10.47.209.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.36; Wed, 14 Dec 2022 20:33:33 -0800 From: Linyu Yuan To: Steven Rostedt , Masami Hiramatsu CC: , , Linyu Yuan Subject: [PATCH v2 2/2] trace: allocate space from temparary trace sequence buffer Date: Thu, 15 Dec 2022 12:33:27 +0800 Message-ID: <1671078807-20748-2-git-send-email-quic_linyyuan@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1671078807-20748-1-git-send-email-quic_linyyuan@quicinc.com> References: <1671078807-20748-1-git-send-email-quic_linyyuan@quicinc.com> MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01b.na.qualcomm.com (10.47.209.197) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: BOQB8jZJ_K0wYp_8eJ9B_q5GbWzlYAnb X-Proofpoint-ORIG-GUID: BOQB8jZJ_K0wYp_8eJ9B_q5GbWzlYAnb X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-15_02,2022-12-14_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 suspectscore=0 phishscore=0 malwarescore=0 impostorscore=0 adultscore=0 clxscore=1015 priorityscore=1501 lowpriorityscore=0 bulkscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2212150031 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org there is one dwc3 trace event declare as below, DECLARE_EVENT_CLASS(dwc3_log_event, TP_PROTO(u32 event, struct dwc3 *dwc), TP_ARGS(event, dwc), TP_STRUCT__entry( __field(u32, event) __field(u32, ep0state) __dynamic_array(char, str, DWC3_MSG_MAX) ), TP_fast_assign( __entry->event = event; __entry->ep0state = dwc->ep0state; ), TP_printk("event (%08x): %s", __entry->event, dwc3_decode_event(__get_str(str), DWC3_MSG_MAX, __entry->event, __entry->ep0state)) ); the problem is when trace function called, it will allocate up to DWC3_MSG_MAX bytes from trace event buffer, but never fill the buffer during fast assignment, it only fill the buffer when output function are called, so this means if output function are not called, the buffer will never used. add __get_buf(len) which allocate space from iter->tmp_seq when trace output function called, it allow user write any data to allocatd space. the mentioned dwc3 trace event will changed as below, DECLARE_EVENT_CLASS(dwc3_log_event, TP_PROTO(u32 event, struct dwc3 *dwc), TP_ARGS(event, dwc), TP_STRUCT__entry( __field(u32, event) __field(u32, ep0state) ), TP_fast_assign( __entry->event = event; __entry->ep0state = dwc->ep0state; ), TP_printk("event (%08x): %s", __entry->event, dwc3_decode_event(__get_buf(DWC3_MSG_MAX), DWC3_MSG_MAX, __entry->event, __entry->ep0state)) );. Signed-off-by: Linyu Yuan --- include/linux/trace_seq.h | 6 ++++++ include/trace/stages/stage3_trace_output.h | 4 ++++ include/trace/stages/stage7_class_define.h | 1 + kernel/trace/trace_seq.c | 31 ++++++++++++++++++++++++++++++ 4 files changed, 42 insertions(+) diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 5a2c650..9703d03 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -95,6 +95,7 @@ extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str, int prefix_type, int rowsize, int groupsize, const void *buf, size_t len, bool ascii); +void *trace_seq_alloc_buffer(struct trace_seq *s, int len); #else /* CONFIG_TRACING */ static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) @@ -138,6 +139,11 @@ static inline int trace_seq_path(struct trace_seq *s, const struct path *path) { return 0; } + +static inline void *trace_seq_alloc_buffer(struct trace_seq *s, int len) +{ + return NULL; +} #endif /* CONFIG_TRACING */ #endif /* _LINUX_TRACE_SEQ_H */ diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h index 66374df..a2921bd 100644 --- a/include/trace/stages/stage3_trace_output.h +++ b/include/trace/stages/stage3_trace_output.h @@ -139,3 +139,7 @@ u64 ____val = (u64)(value); \ (u32) do_div(____val, NSEC_PER_SEC); \ }) + +#undef __get_buf +#define __get_buf(len) \ + trace_seq_alloc_buffer(p, len) diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h index 8795429..bcb960d 100644 --- a/include/trace/stages/stage7_class_define.h +++ b/include/trace/stages/stage7_class_define.h @@ -23,6 +23,7 @@ #undef __get_rel_sockaddr #undef __print_array #undef __print_hex_dump +#undef __get_buf /* * The below is not executed in the kernel. It is only what is diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 9c90b3a..1501e3b 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -403,3 +403,34 @@ int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str, return 1; } EXPORT_SYMBOL(trace_seq_hex_dump); + +/** + * trace_seq_alloc_buffer - allocate seq buffer with size len + * @s: trace sequence descriptor + * @len: size of buffer to be allocated + * + * allocate space with size of @len from seq buffer for output usage, + * On success, it returns start address of the allocated buffer, + * user can fill data start from the address, user should make sure the + * data length not exceed the @len, if it exceed, behavior is undefined. + * + * Returns NULL if no buffer can be allocated, it also means system will + * crash, it is user responsiblity to make sure total buffer used will + * not exceed PAGE_SIZE. + * + * it allow multiple usage in one trace output function call. + */ +void *trace_seq_alloc_buffer(struct trace_seq *s, int len) +{ + char *buf = trace_seq_buffer_ptr(s); + + seq_buf_commit(&s->seq, len); + + if (unlikely(seq_buf_has_overflowed(&s->seq))) { + s->full = 1; + return NULL; + } + + return (void *)buf; +} +EXPORT_SYMBOL(trace_seq_alloc_buffer);