From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752897AbdGLThI (ORCPT ); Wed, 12 Jul 2017 15:37:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:58920 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751036AbdGLThD (ORCPT ); Wed, 12 Jul 2017 15:37:03 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13DDA22C9C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , David Ahern , Hendrik Brueckner , Jiri Olsa , Namhyung Kim , Wang Nan , Zvonko Kosic Subject: [PATCH 1/1] perf symbols: Accept zero as the kernel base address Date: Wed, 12 Jul 2017 16:36:50 -0300 Message-Id: <20170712193650.32245-2-acme@kernel.org> X-Mailer: git-send-email 2.9.4 In-Reply-To: <20170712193650.32245-1-acme@kernel.org> References: <20170712193650.32245-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo Which is the case in S/390, where symbols were not being resolved because machine__get_kernel_start was only setting machine->kernel_start when the just successfully loaded kernel symtab had its map->start set to !0, when it was left at (1ULL << 63) assuming a partitioning of the address space for user/kernel, which is not the case in S/390 nor in Sparc. So just check if map__load() was successfull and set machine->kernel_start to zero, fixing kernel symbol resolution on S/390. Test performed by Thomas: ---- I like this patch. I have done a new build and removed all my debug output to start from scratch. Without your patch I get this: # Samples: 4 of event 'cpu-clock' # Event count (approx.): 1000000 # # Children Self Command Shared Object Symbol # ........ ........ ....... ................ ........................ 75.00% 0.00% true [unknown] [k] 0x00000000004bedda | ---0x4bedda | |--50.00%--0x42693a | | | --25.00%--0x2a72e0 | 0x2af0ca | 0x3d1003fe4c0 | --25.00%--0x4272bc 0x26fa84 and with your patch (I just rebuilt the perf tool, nothing else and used the same perf.data file as input): # Samples: 4 of event 'cpu-clock' # Event count (approx.): 1000000 # # Children Self Command Shared Object Symbol # ........ ........ ....... .......................... .................................. 75.00% 0.00% true [kernel.vmlinux] [k] pgm_check_handler | ---pgm_check_handler do_dat_exception handle_mm_fault __handle_mm_fault filemap_map_pages | |--25.00%--rcu_read_lock_held | rcu_lockdep_current_cpu_online | 0x3d1003ff4c0 | --25.00%--lock_release Looks good to me.... ---- Reported-and-Tested-by: Thomas-Mich Richter Cc: Adrian Hunter Cc: David Ahern Cc: Hendrik Brueckner Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Cc: Zvonko Kosic Link: http://lkml.kernel.org/n/tip-dk0n1uzmbe0tbthrpfqlx6bz@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 5de2b86b9880..2e9eb6aa3ce2 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2209,7 +2209,7 @@ int machine__get_kernel_start(struct machine *machine) machine->kernel_start = 1ULL << 63; if (map) { err = map__load(map); - if (map->start) + if (!err) machine->kernel_start = map->start; } return err; -- 2.9.4