From mboxrd@z Thu Jan 1 00:00:00 1970 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 2D870C4332F for ; Mon, 24 Jan 2022 20:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352334AbiAXUj2 (ORCPT ); Mon, 24 Jan 2022 15:39:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384954AbiAXUeT (ORCPT ); Mon, 24 Jan 2022 15:34:19 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 074F1C07E2B7; Mon, 24 Jan 2022 11:47:52 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A203B61031; Mon, 24 Jan 2022 19:47:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A19C340E5; Mon, 24 Jan 2022 19:47:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643053670; bh=H0Nf65V8r/RvVEwCt8j9T0Es3uLNGZIIW5tsXERlElY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uFbLQqYVtTq0HCRZxhcyWur1rEeVYSBSTA+aXuejyY6QTORT4/2JdiM06gTgTi5dm BjC6OdNVXYvpJBb75NhY5bXNttV1hVAJozAJcdRWswcRTf3CHog0YE5PmHu8Vdro0H RTU53KGEb3O5iR8GYX9kucUMGtyEuxwNnLJdYqpQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Kajol Jain , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.10 138/563] bpf: Remove config check to enable bpf support for branch records Date: Mon, 24 Jan 2022 19:38:23 +0100 Message-Id: <20220124184029.173197383@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184024.407936072@linuxfoundation.org> References: <20220124184024.407936072@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kajol Jain [ Upstream commit db52f57211b4e45f0ebb274e2c877b211dc18591 ] Branch data available to BPF programs can be very useful to get stack traces out of userspace application. Commit fff7b64355ea ("bpf: Add bpf_read_branch_records() helper") added BPF support to capture branch records in x86. Enable this feature also for other architectures as well by removing checks specific to x86. If an architecture doesn't support branch records, bpf_read_branch_records() still has appropriate checks and it will return an -EINVAL in that scenario. Based on UAPI helper doc in include/uapi/linux/bpf.h, unsupported architectures should return -ENOENT in such case. Hence, update the appropriate check to return -ENOENT instead. Selftest 'perf_branches' result on power9 machine which has the branch stacks support: - Before this patch: [command]# ./test_progs -t perf_branches #88/1 perf_branches/perf_branches_hw:FAIL #88/2 perf_branches/perf_branches_no_hw:OK #88 perf_branches:FAIL Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED - After this patch: [command]# ./test_progs -t perf_branches #88/1 perf_branches/perf_branches_hw:OK #88/2 perf_branches/perf_branches_no_hw:OK #88 perf_branches:OK Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED Selftest 'perf_branches' result on power9 machine which doesn't have branch stack report: - After this patch: [command]# ./test_progs -t perf_branches #88/1 perf_branches/perf_branches_hw:SKIP #88/2 perf_branches/perf_branches_no_hw:OK #88 perf_branches:OK Summary: 1/1 PASSED, 1 SKIPPED, 0 FAILED Fixes: fff7b64355eac ("bpf: Add bpf_read_branch_records() helper") Suggested-by: Peter Zijlstra Signed-off-by: Kajol Jain Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211206073315.77432-1-kjain@linux.ibm.com Signed-off-by: Sasha Levin --- kernel/trace/bpf_trace.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index ba644760f5076..a9e074769881f 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1517,9 +1517,6 @@ static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, void *, buf, u32, size, u64, flags) { -#ifndef CONFIG_X86 - return -ENOENT; -#else static const u32 br_entry_size = sizeof(struct perf_branch_entry); struct perf_branch_stack *br_stack = ctx->data->br_stack; u32 to_copy; @@ -1528,7 +1525,7 @@ BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, return -EINVAL; if (unlikely(!br_stack)) - return -EINVAL; + return -ENOENT; if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE) return br_stack->nr * br_entry_size; @@ -1540,7 +1537,6 @@ BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx, memcpy(buf, br_stack->entries, to_copy); return to_copy; -#endif } static const struct bpf_func_proto bpf_read_branch_records_proto = { -- 2.34.1