From patchwork Wed Jun 28 23:10:21 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thiago Jung Bauermann X-Patchwork-Id: 781956 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wydtw2vWBz9s72 for ; Thu, 29 Jun 2017 09:15:36 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3wydtw204vzDr6k for ; Thu, 29 Jun 2017 09:15:36 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wydnP61rpzDr4v for ; Thu, 29 Jun 2017 09:10:49 +1000 (AEST) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5SN3cCt066995 for ; Wed, 28 Jun 2017 19:10:47 -0400 Received: from e24smtp05.br.ibm.com (e24smtp05.br.ibm.com [32.104.18.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bcfq6yj3y-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 28 Jun 2017 19:10:47 -0400 Received: from localhost by e24smtp05.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 28 Jun 2017 20:10:43 -0300 Received: from d24av01.br.ibm.com (d24av01.br.ibm.com [9.8.31.91]) by d24relay02.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v5SNAhF318284548 for ; Wed, 28 Jun 2017 20:10:43 -0300 Received: from d24av01.br.ibm.com (localhost [127.0.0.1]) by d24av01.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v5SNAhLi018508 for ; Wed, 28 Jun 2017 20:10:43 -0300 Received: from morokweng.ibm.com ([9.80.228.26]) by d24av01.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id v5SNAZT4018415; Wed, 28 Jun 2017 20:10:42 -0300 From: Thiago Jung Bauermann To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 3/8] powerpc/perf/hv-24x7: Properly iterate through results Date: Wed, 28 Jun 2017 20:10:21 -0300 X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170628231026.23190-1-bauerman@linux.vnet.ibm.com> References: <20170628231026.23190-1-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable x-cbid: 17062823-0032-0000-0000-0000056EFD82 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17062823-0033-0000-0000-000011F55FA6 Message-Id: <20170628231026.23190-4-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-06-28_14:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706280369 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thiago Jung Bauermann , Sukadev Bhattiprolu Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" hv-24x7.h has a comment mentioning that result_buffer->results can't be indexed as a normal array because it may contain results of variable sizes, so fix the loop in h_24x7_event_commit_txn to take the variation into account when iterating through results. Another problem in that loop is that it sets h24x7hw->events[i] to NULL. This assumes that only the i'th result maps to the i'th request, but that is not guaranteed to be true. We need to leave the event in the array so that we don't dereference a NULL pointer in case more than one result maps to one request. We still assume that each result has only one result element, so warn if that assumption is violated. Signed-off-by: Thiago Jung Bauermann --- arch/powerpc/perf/hv-24x7.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 141de0f708f7..8b1a3e849d23 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -1144,7 +1144,9 @@ static int add_event_to_24x7_request(struct perf_event *event, static unsigned long single_24x7_request(struct perf_event *event, u64 *count) { + u16 num_elements; unsigned long ret; + struct hv_24x7_result *result; struct hv_24x7_request_buffer *request_buffer; struct hv_24x7_data_result_buffer *result_buffer; @@ -1166,8 +1168,14 @@ static unsigned long single_24x7_request(struct perf_event *event, u64 *count) goto out; } + result = result_buffer->results; + + /* This code assumes that a result has only one element. */ + num_elements = be16_to_cpu(result->num_elements_returned); + WARN_ON_ONCE(num_elements != 1); + /* process result from hcall */ - *count = be64_to_cpu(result_buffer->results[0].elements[0].element_data[0]); + *count = be64_to_cpu(result->elements[0].element_data[0]); out: put_cpu_var(hv_24x7_reqb); @@ -1400,8 +1408,7 @@ static int h_24x7_event_commit_txn(struct pmu *pmu) { struct hv_24x7_request_buffer *request_buffer; struct hv_24x7_data_result_buffer *result_buffer; - struct hv_24x7_result *resb; - struct perf_event *event; + struct hv_24x7_result *res, *next_res; u64 count; int i, ret, txn_flags; struct hv_24x7_hw *h24x7hw; @@ -1428,13 +1435,20 @@ static int h_24x7_event_commit_txn(struct pmu *pmu) h24x7hw = &get_cpu_var(hv_24x7_hw); - /* Update event counts from hcall */ - for (i = 0; i < request_buffer->num_requests; i++) { - resb = &result_buffer->results[i]; - count = be64_to_cpu(resb->elements[0].element_data[0]); - event = h24x7hw->events[i]; - h24x7hw->events[i] = NULL; + /* Go through results in the result buffer to update event counts. */ + for (i = 0, res = result_buffer->results; + i < result_buffer->num_results; i++, res = next_res) { + struct perf_event *event = h24x7hw->events[res->result_ix]; + u16 num_elements = be16_to_cpu(res->num_elements_returned); + u16 data_size = be16_to_cpu(res->result_element_data_size); + + /* This code assumes that a result has only one element. */ + WARN_ON_ONCE(num_elements != 1); + + count = be64_to_cpu(res->elements[0].element_data[0]); update_event_count(event, count); + + next_res = (void *) res->elements[0].element_data + data_size; } put_cpu_var(hv_24x7_hw);