From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f69.google.com (mail-pj1-f69.google.com [209.85.216.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E07D13BA246 for ; Fri, 7 Aug 2026 07:18:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786087114; cv=none; b=sxKMh1HtCqowo8d138I2RJvdL6YroLP/zbAyBgkNObkwgZqRy0iYsHYRxgROSP7My9BiB8ZOBvlxm2aR+Q2Gq/CppaInsV0EB1fM0tm6JFYVELTzisurdj7CHMD/aujPBNKw0MxGFV61KBx2zTj/pReWcD/3fCcWe6cjDnOCGvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786087114; c=relaxed/simple; bh=cpzuJlngGAm43tFscMlXRZnMARJWPTr0CBcPuQjRuwk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=OkSMPcGIyTpHK4whzjvYtuUs/TEgyjv0O/9clWXal1QCjmd0CpqB1iIpGQWdoT1UjhvA/sXRaXR4RAHRfjAS9iUfHhhORrFu5aikY0LbH5P59f6/NAnyki2tDZDNocswHtjNd5IagZ9FG9zahgu19EO5oklK6B238AITNINrduk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=tmz1Nh3U; arc=none smtp.client-ip=209.85.216.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="tmz1Nh3U" Received: by mail-pj1-f69.google.com with SMTP id 98e67ed59e1d1-38f5ac7416eso3791322a91.3 for ; Fri, 07 Aug 2026 00:18:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786087111; x=1786691911; darn=vger.kernel.org; h=content-type:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Bcl1RSiBLZ6miVSqvsuamblwEoHgWcooZQBMrgJQ6Do=; b=tmz1Nh3UxVxDDDGNhoshXuYXF3gKWvhFUBSf5Z0hK8J7224n2DQQNB8CN2LWP5nu9S WfcD45hBaOWS3wxFtyZr/zJVSBcicvWGbPZnN+kZfuQlg8uRaTDxXDXIkKwMOGiRvLMr SAwFnnqaYeEm3PSi3dCNleIQczulVaZsauFWymsE/9Qec4Vre5nrlFGkElH4F/q+QSj2 1zN3vDOy9Ip9OFnx0qsDkBjiG0+qWjJYLwin+7D1WrZfyF2e6XqS9YxnyRM6UYGJdejT nnchRa6BI6F7sytMV2+4pj+KWn7ybS82BZw6+P23upCBcdT8VYNu6PJe8vt/5q+L4Ajh Q5Dg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786087111; x=1786691911; h=content-type:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Bcl1RSiBLZ6miVSqvsuamblwEoHgWcooZQBMrgJQ6Do=; b=D3dfdGuoh2+VDFh6/k1R5ZKEJR7IuNGMvWIi8XsrvGmJlK/Va1IKxwSqt7+/1cQuU+ ScU4y3+wO/35Oy/HqbQgkbUDZvDuwl//d2DYm8Nf9F/RsyvoZ3uk50ShTQkLOkRCMBTf OD3Augrxm1LHkLFIVhVv36h5XXvdZvJ6pzQlQ3Knr/c16jbyGQ4Ux9wmRONLeB4SVjZp g7Ztt9XXer5z5IPiIv+1CjSvQmJhYsUDGBywuoqfp6+o3L5E7/sgBnM/Emi05wELA/Xx KxqSrbszAKKz3U1j/FeRm3WfkaZUbSM328mWYMWuwlvAUY/d0jXpA2KFXyp1dCgnk8WA CZXA== X-Forwarded-Encrypted: i=1; AHgh+RrWxfQCO4o15xEZemHhGfQO5VxEJ7IvK/pLw6z+h+yuG6CBc2X29P6w34UL/8+cTFNCvpXpB2QLZ+9pCSTc6bLR@vger.kernel.org X-Gm-Message-State: AOJu0Yxo5CE0iBtCrS47atYpNht/KEe5DQlwZHdaf0EBOCnR/CloDvy+ WiX4j2T/bjAzOLlTbVYtN/eyLJ5Px+ZEhm0ZrkcKmUuqG/LUWhyTyosbn5qAQ/94h1P8cT22S0G GBob1ssSG4Q== X-Received: from dled12-n2.prod.google.com ([2002:a05:701b:42cc:20b0:13b:9ad0:582f]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1e53:b0:381:1f51:1ff0 with SMTP id 98e67ed59e1d1-3903c54b3a1mr18644417a91.2.1786087110681; Fri, 07 Aug 2026 00:18:30 -0700 (PDT) Date: Fri, 7 Aug 2026 00:18:13 -0700 In-Reply-To: <20260807071818.718751-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260807071818.718751-1-irogers@google.com> X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260807071818.718751-4-irogers@google.com> Subject: [RFC PATCH v1 3/8] perf/core: Implement BUILD_ID_OFFSET sample type From: Ian Rogers To: Steven Rostedt , Masami Hiramatsu , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Ian Rogers , Adrian Hunter , James Clark , Suzuki K Poulose , Mike Leach , Leo Yan , John Garry , Will Deacon , Thomas Gleixner , Dapeng Mi , Ravi Bangoria , Swapnil Sapkal , Thomas Falcon , Thomas Richter , Dmitrii Dolgov <9erthalion6@gmail.com>, Eric Biggers , Zecheng Li , Gabriel Marin , Tengda Wu , Derek Foreman , Tanushree Shah , Ankur Arora , Aaron Tomlin , tanze , Rui Qi , Howard Chu , Chuck Lever , Shimin Guo , Alessio Podda , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="UTF-8" Expose stack_map_get_build_id_offset for perf_events to use when generating these samples, and implement the payload writing in the perf event core. Signed-off-by: Ian Rogers --- include/linux/bpf.h | 13 +++++++ kernel/bpf/stackmap.c | 2 +- kernel/events/core.c | 85 ++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 98 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7719f6528445..fd76900a8e47 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -4209,4 +4209,17 @@ static inline int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 all return 0; } +struct bpf_stack_build_id; +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PERF_EVENTS) +void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, + u32 trace_nr, bool user, bool may_fault); +#else +static inline void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, + u32 trace_nr, bool user, bool may_fault) +{ + if (id_offs) + id_offs->status = 1; /* BPF_STACK_BUILD_ID_EMPTY */ +} +#endif + #endif /* _LINUX_BPF_H */ diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 41fe87d7302f..889ceb7cf29b 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -411,7 +411,7 @@ static void stack_map_get_build_id_offset_sleepable(struct bpf_stack_build_id *i * id_offs[i].build_id is zeroed out and id_offs[i].status is set to * BPF_STACK_BUILD_ID_IP. */ -static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, +void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, u32 trace_nr, bool user, bool may_fault) { struct mmap_unlock_irq_work *work = NULL; diff --git a/kernel/events/core.c b/kernel/events/core.c index ba5bd6a78fe7..97ac70441602 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2048,6 +2048,15 @@ static int __perf_event_read_size(u64 read_format, int nr_siblings) return size + nr * entry; } + +struct perf_sample_build_id_offset { + u8 size; + u8 res1; + u16 res2; + u8 build_id[BPF_BUILD_ID_SIZE]; + u64 offset; +}; + static void __perf_event_header_size(struct perf_event *event, u64 sample_type) { struct perf_sample_data *data; @@ -2086,6 +2095,11 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type) if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) size += sizeof(data->code_page_size); + if (sample_type & PERF_SAMPLE_BUILD_ID_OFFSET) + size += sizeof(struct perf_sample_build_id_offset); + + + event->header_size = size; } @@ -8287,6 +8301,62 @@ void perf_output_sample(struct perf_output_handle *handle, if (sample_type & PERF_SAMPLE_READ) perf_output_read(handle, event); + if (sample_type & PERF_SAMPLE_BUILD_ID_OFFSET) { + struct bpf_stack_build_id bpf_bid = { .ip = data->ip }; + struct perf_sample_build_id_offset bid_offset = { 0 }; + + bool is_user = (header->misc & PERF_RECORD_MISC_CPUMODE_MASK) == + PERF_RECORD_MISC_USER; + + stack_map_get_build_id_offset( + &bpf_bid, /*trace_nr=*/1, + is_user, /*may_fault=*/false); + if (bpf_bid.status == BPF_STACK_BUILD_ID_VALID) { + bid_offset.size = BPF_BUILD_ID_SIZE; + memcpy(bid_offset.build_id, bpf_bid.build_id, + BPF_BUILD_ID_SIZE); + bid_offset.offset = bpf_bid.offset; + } else { + bid_offset.offset = bpf_bid.ip; + } + perf_output_put(handle, bid_offset); + } + + if (sample_type & PERF_SAMPLE_CALLCHAIN_BUILD_ID_OFFSET) { + u64 nr = data->callchain ? data->callchain->nr : 0; + struct perf_sample_build_id_offset bid_offset; + struct bpf_stack_build_id bpf_bid; + u64 i; + + perf_output_put(handle, nr); + + for (i = 0; i < nr; i++) { + memset(&bid_offset, /*c=*/0, sizeof(bid_offset)); + memset(&bpf_bid, /*c=*/0, sizeof(bpf_bid)); + bpf_bid.ip = data->callchain->ip[i]; + + if (data->callchain->ip[i] == PERF_CONTEXT_USER) { + bpf_bid.status = BPF_STACK_BUILD_ID_EMPTY; + } else { + bool is_user = data->callchain->ip[i] < PERF_CONTEXT_MAX; + + stack_map_get_build_id_offset(&bpf_bid, /*trace_nr=*/1, + is_user, /*may_fault=*/false); + } + + if (bpf_bid.status == BPF_STACK_BUILD_ID_VALID) { + bid_offset.size = BPF_BUILD_ID_SIZE; + memcpy(bid_offset.build_id, bpf_bid.build_id, + BPF_BUILD_ID_SIZE); + bid_offset.offset = bpf_bid.offset; + } else { + bid_offset.offset = bpf_bid.ip; + } + perf_output_put(handle, bid_offset); + } + } + + if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; @@ -8632,7 +8702,7 @@ void perf_prepare_sample(struct perf_sample_data *data, __perf_event_header__init_id(data, event, filtered_sample_type); - if (filtered_sample_type & PERF_SAMPLE_IP) { + if (filtered_sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_BUILD_ID_OFFSET)) { data->ip = perf_instruction_pointer(event, regs); data->sample_flags |= PERF_SAMPLE_IP; } @@ -8640,6 +8710,19 @@ void perf_prepare_sample(struct perf_sample_data *data, if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) perf_sample_save_callchain(data, event, regs); + if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN_BUILD_ID_OFFSET) { + int size = 1; + + if (!data->callchain) + data->callchain = perf_callchain(event, regs); + + size += data->callchain->nr * + (sizeof(struct perf_sample_build_id_offset) / sizeof(u64)); + data->dyn_size += size * sizeof(u64); + data->sample_flags |= PERF_SAMPLE_CALLCHAIN_BUILD_ID_OFFSET; + } + + if (filtered_sample_type & PERF_SAMPLE_RAW) { data->raw = NULL; data->dyn_size += sizeof(u64); -- 2.55.0.679.g6767b8d81c-goog