From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751889AbbD3DFN (ORCPT ); Wed, 29 Apr 2015 23:05:13 -0400 Received: from e17.ny.us.ibm.com ([129.33.205.207]:59755 "EHLO e17.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751374AbbD3DFJ (ORCPT ); Wed, 29 Apr 2015 23:05:09 -0400 From: Sukadev Bhattiprolu To: Paul Mackerras , Michael Ellerman Cc: dev@codyps.com, gusld@br.ibm.com, , linuxppc-dev@lists.ozlabs.org Subject: [PATCH 1/1] powerpc/hv-24x7: Check support before registering PMU Date: Wed, 29 Apr 2015 20:04:51 -0700 Message-Id: <1430363091-27722-1-git-send-email-sukadev@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15043003-0041-0000-0000-000000317D6A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We currently try to register the 24x7 PMU unconditionally. Not all Power systems support 24x7 counters (eg: Power7). On these systems we get a backtrace during boot when trying to register the 24x7 PMU. Check if the hypervisor supports 24x7 counters before attempting to register the 24x7 PMU. Reported-by: Gustavo Luiz Duarte Signed-off-by: Sukadev Bhattiprolu --- arch/powerpc/perf/hv-24x7.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index ec2eb20..19a59a3 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -1268,12 +1268,44 @@ static struct pmu h_24x7_pmu = { .read = h_24x7_event_read, }; +/* + * Return 1 if we can access the 24x7 counter catalog from the hypervisor. + * Return 0 otherwise. + */ +static int hv_has_24x7(void) +{ + int page_size = 4096; + unsigned long hret; + void *page; + struct hv_24x7_catalog_page_0 *page_0; + + page_0 = kmalloc(page_size*2, GFP_KERNEL); + if (!page_0) + return 0; + + /* buffer for catalog needs to be 4K-aligned */ + page = (void *)((long)page_0 & (~page_size-1)) + page_size; + hret = h_get_24x7_catalog_page(page, 0, 0); + kfree(page_0); + + if (hret) { + pr_devel("Error %ld reading catalog, disabling 24x7 PMU\n", hret); + return 0; + } + + return 1; +} + + static int hv_24x7_init(void) { int r; unsigned long hret; struct hv_perf_caps caps; + if (!hv_has_24x7()) + return -ENODEV; + if (!firmware_has_feature(FW_FEATURE_LPAR)) { pr_debug("not a virtualized system, not enabling\n"); return -ENODEV; -- 1.8.3.1