From patchwork Thu Jul 28 23:33:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beau Belgrave X-Patchwork-Id: 12931809 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 6803AC25B06 for ; Thu, 28 Jul 2022 23:33:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233609AbiG1XdP (ORCPT ); Thu, 28 Jul 2022 19:33:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232341AbiG1XdO (ORCPT ); Thu, 28 Jul 2022 19:33:14 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6F676785B4; Thu, 28 Jul 2022 16:33:13 -0700 (PDT) Received: from localhost.localdomain (unknown [76.135.27.191]) by linux.microsoft.com (Postfix) with ESMTPSA id 04EBF20FE89F; Thu, 28 Jul 2022 16:33:12 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 04EBF20FE89F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1659051193; bh=OshzEQjcp6ojnzn5LYBE1eu+Sux/uhH/cej6HEpEacI=; h=From:To:Cc:Subject:Date:From; b=duK7k3kdRNu8EiO0bF/fGZpcVmVhaBthPG6vfHLTgpg1eGtKUD1B3YpYqa0MQGits ilsdQlFOYPSnY79642iiV0V7fYWc9gzZsNxz5RjVqrNEuXRSGBNVKD9t6WdAySb8+X xcU+y9fupa22/4MmtYju1MXKsvCjWehgRkyIb+T0= From: Beau Belgrave To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com Cc: linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, beaub@linux.microsoft.com Subject: [PATCH v3 0/6] tracing/user_events: Update user_events ABI from Date: Thu, 28 Jul 2022 16:33:03 -0700 Message-Id: <20220728233309.1896-1-beaub@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org This series covers the changes that were brought up once user_events went into 5.18. The largest change is moving away from byte index to a bit index, as first suggested by Mathieu Desnoyers. The other changes are either fixes that have accumulated or found by Mathieu. NOTE: The sample and self-tests do not build unless you manually install user_events.h into usr/include/linux. Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/ Psuedo code example of typical usage with the new ABI: struct user_reg reg; int page_fd = open("user_events_status", O_RDWR); char *page_data = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, page_fd, 0); close(page_fd); int data_fd = open("user_events_data", O_RDWR); reg.size = sizeof(reg); reg.name_args = (__u64)"test"; ioctl(data_fd, DIAG_IOCSREG, ®); int status_id = reg.status_bit / 8; int status_mask = 1 << (reg.status_bit % 8); int write_id = reg.write_index; struct iovec io[2]; io[0].iov_base = &write_id; io[0].iov_len = sizeof(write_id); io[1].iov_base = payload; io[1].iov_len = sizeof(payload); if (page_data[status_id] & status_mask) writev(data_fd, io, 2); V2 Updates: Changed from status_index and status_mask on user_reg to just status_bit. Updated and added byte-wise and long-wise indexing pattern into docs. Updated tests to use byte-wise index pattern. Updated sample to show long-wise index pattern. V3 Updates: Rebase to recent ftrace/core head. Updated comments to show how index/bit to byte is calculated. Changed to BIT() macro vs 1 << X. Beau Belgrave (6): tracing/user_events: Use NULL for strstr checks tracing/user_events: Use WRITE instead of READ for io vector import tracing/user_events: Ensure user provided strings are safely formatted tracing/user_events: Use refcount instead of atomic for ref tracking tracing/user_events: Use bits vs bytes for enabled status page data tracing/user_events: Update ABI documentation to align to bits vs bytes Documentation/trace/user_events.rst | 86 ++++--- include/linux/user_events.h | 15 +- kernel/trace/trace_events_user.c | 228 ++++++++++++------ samples/user_events/example.c | 25 +- .../selftests/user_events/ftrace_test.c | 47 +++- .../testing/selftests/user_events/perf_test.c | 11 +- 6 files changed, 281 insertions(+), 131 deletions(-) base-commit: 26b2da5fc0b41a9a6a5e30b858da28572a6f4cbc