From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753798AbeDSXU1 (ORCPT ); Thu, 19 Apr 2018 19:20:27 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:43382 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753537AbeDSXU0 (ORCPT ); Thu, 19 Apr 2018 19:20:26 -0400 Date: Thu, 19 Apr 2018 18:20:24 -0500 From: Kim Phillips To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Jiri Olsa , Ingo Molnar , Peter Zijlstra , Jiri Olsa , LKML , Subject: Re: [PATCH] perf tools: set kernel end address properly Message-Id: <20180419182024.5d3bc71deef99551cc19fc55@arm.com> In-Reply-To: <20180419023712.GB13370@sejong> References: <20180416042240.21528-1-namhyung@kernel.org> <20180416092345.GA23274@krava> <20180416135125.GA23802@kernel.org> <20180416110730.1dd12801e43be66ea5d0cc48@arm.com> <20180416165800.GD3202@kernel.org> <20180416122407.0d90863b69fed80166384850@arm.com> <20180416174811.1aca9106364effe435f363c8@arm.com> <20180417022726.GA31947@sejong> <20180418193759.b63912fe5e5b8a9023ec80a8@arm.com> <20180419023712.GB13370@sejong> Organization: Arm X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Apr 2018 11:37:12 +0900 Namhyung Kim wrote: > On Wed, Apr 18, 2018 at 07:37:59PM -0500, Kim Phillips wrote: > > On Tue, 17 Apr 2018 11:27:26 +0900 > > Namhyung Kim wrote: > > > On Mon, Apr 16, 2018 at 05:48:11PM -0500, Kim Phillips wrote: > > > > > a perf/urgent from last week (commit 918965d4897) + this patch: > > > > > > > > > > $ sudo ./perf test -vv 1 |& head > > > > > 1: vmlinux symtab matches kallsyms : > > > > > --- start --- > > > > > test child forked, pid 6194 > > > > > Looking at the vmlinux_path (8 entries long) > > > > > Using /lib/modules/4.16.0+/build/vmlinux for symbols > > > > > ERR : 0xffff200008081000: do_undefinstr not on kallsyms > > > > > ERR : 0xffff2000080810b8: do_sysinstr not on kallsyms > > > > > ERR : 0xffff200008081258: do_debug_exception not on kallsyms > > > > > ERR : 0xffff200008081648: do_mem_abort not on kallsyms > > > > > ERR : 0xffff2000080818b8: do_el0_irq_bp_hardening not on kallsyms > > > > > $ sudo ./perf test -vv 1 |& tail > > > > > ERR : 0xffff20000a1d37c8: tramp_exit_native not on kallsyms > > > > > ERR : 0xffff20000a1d37e8: tramp_exit_compat not on kallsyms > > > > > ERR : 0xffff20000a1d4000: __entry_tramp_text_end not on kallsyms > > > > > WARN: Maps only in vmlinux: > > > > > ffff200008080000-ffff200008081000 10000 [kernel].head.text > > > > > ffff20000aec0000-ffff20000aff7548 2e50000 [kernel].init.text > > > > > ffff20000aff7548-ffff20000b0126d4 2f87548 [kernel].exit.text > > > > > test child finished with -1 > > > > > ---- end ---- > > > > > vmlinux symtab matches kallsyms: FAILED! > > > > > > > > this patch's advertised "If there's no module after the kernel map, the > > > > end address will be ~0ULL." doesn't seem to be working: the value it > > > > gets for 'end' is 0xffff200008080000. > > > > > > For the vmlinux, right? > > > > yes, map__next(machine__kernel_map(machine)) has the start address > > of the single module currently loaded: > > > > ffff200002290000 t $x [arm_ccn] > > ffff200002290000 t arm_ccn_pmu_events_is_visible [arm_ccn] > > > > The beginning of the kernel is..later: > > > > ffff200008080000 t _head > > ffff200008080000 T _text > > > > and its end according to grep -w _end /proc/kallsyms is: > > > > ffff20000d5f9000 B _end > > > > but end was assigned to the beginning of arm_ccn (0xffff200002290000), > > which is upside-down. > > So ARM64 has modules below the kernel. right. > > > To be precise, it should be "If there's no map after the kernel map". > > > > In numerical address order, in maps in map_groups__insert order, or > > some other order? > > The map_groups__insert() also sorts the map by address, so they should Had missed that, sorry. > be identical. I think the problem is perf assumes the kernel is the > first map in the kmaps. When it calls maps_groups__insert() it uses > start address of 0 for the kernel map. It seems always true for x86 > but not for ARM64. > > While it changes the start address in machine__set_kernel_mmap() it > doesn't change the order in the kmaps. > > Could you please test below patch (on top) then? Much better, thank you! Together with the "module_emit_adrp_veneer not on kallsyms" mitigation diff, test 1 now passes on arm64 systems both with modules loaded, and without, and with and without RANDOMIZE_BASE. I would send a patch (From: you), but I think you'd do a better job on writing the commit text, so would you care to, please? Thanks, Kim