From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757008Ab3A2N5b (ORCPT ); Tue, 29 Jan 2013 08:57:31 -0500 Received: from goliath.siemens.de ([192.35.17.28]:15060 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756569Ab3A2N53 (ORCPT ); Tue, 29 Jan 2013 08:57:29 -0500 Message-ID: <5107D528.2010305@siemens.com> Date: Tue, 29 Jan 2013 14:56:56 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Borislav Petkov , Andrew Morton , linux-kernel@vger.kernel.org, Jason Wessel , kgdb-bugreport@lists.sourceforge.net, Andi Kleen , Tom Tromey , Ben Widawsky , "David S. Miller" , sparclinux@vger.kernel.org Subject: Re: [PATCH v5 16/20] scripts/gdb: Add internal helper and convenience function for per-cpu lookup References: <04960fa208fbd9c0962eb4f70aa45d28aec59e8d.1359463075.git.jan.kiszka@siemens.com> <20130129135109.GF14302@pd.tnic> In-Reply-To: <20130129135109.GF14302@pd.tnic> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2013-01-29 14:51, Borislav Petkov wrote: > On Tue, Jan 29, 2013 at 01:37:59PM +0100, Jan Kiszka wrote: >> This function allows to obtain a per-cpu variable, either of the current >> or an explicitly specified CPU. >> >> Note: sparc64 version is untested. >> >> CC: "David S. Miller" >> CC: sparclinux@vger.kernel.org >> Signed-off-by: Jan Kiszka >> --- >> scripts/gdb/percpu.py | 61 ++++++++++++++++++++++++++++++++++++++++++++ >> scripts/gdb/vmlinux-gdb.py | 1 + >> 2 files changed, 62 insertions(+), 0 deletions(-) >> create mode 100644 scripts/gdb/percpu.py >> >> diff --git a/scripts/gdb/percpu.py b/scripts/gdb/percpu.py >> new file mode 100644 >> index 0000000..864962c >> --- /dev/null >> +++ b/scripts/gdb/percpu.py >> @@ -0,0 +1,61 @@ >> +# >> +# gdb helper commands and functions for Linux kernel debugging >> +# >> +# per-cpu tools > > This is actually a very cool thing for CPU guys: it can show what kind > of hybrid CPUs they've been glueing together, like the following, for > example: > > ... > (gdb) p $lx_per_cpu("cpu_info").x86_virt_bits > $5 = 48 '0' > (gdb) p $lx_per_cpu("cpu_info").x86_vendor_id > $6 = "GenuineIntel\000\000\000" > (gdb) p $lx_per_cpu("cpu_info").x86_model_id > $7 = "AMD Phenom(tm) 9550 Quad-Core Processor", '\000' > (gdb) > > Since when does Intel produce CPUs called "AMD Phenom(tm) 9550 Quad-Core > Processor"? .. hahaha.. Let me guess: You are dumping a weird QEMU/KVM CPU, right? > >> +# >> +# Copyright (c) Siemens AG, 2011-2013 >> +# >> +# Authors: >> +# Jan Kiszka >> +# >> +# This work is licensed under the terms of the GNU GPL version 2. >> +# >> + >> +import gdb >> + >> +from utils import * >> +from task import * >> + >> +MAX_CPUS = 4096 >> + >> +def get_current_cpu(): >> + if get_gdbserver_type() == GDBSERVER_QEMU: >> + return gdb.selected_thread().num - 1 >> + elif get_gdbserver_type() == GDBSERVER_KGDB: >> + tid = gdb.selected_thread().ptid[2] >> + if tid > (0x100000000 - MAX_CPUS - 2): >> + return 0x100000000 - tid - 2 >> + else: >> + return get_thread_info(get_task_by_pid(tid))['cpu'] >> + else: >> + raise gdb.GdbError("Sorry, obtaining the current CPU is " >> + "not yet supported with this gdb server.") >> + >> +def per_cpu(var_ptr, cpu): >> + if cpu == -1: >> + cpu = get_current_cpu() >> + if is_target_arch("sparc:v9"): >> + offset = gdb.parse_and_eval("trap_block[" + str(cpu) + >> + "].__per_cpu_base") >> + else: >> + offset = gdb.parse_and_eval("__per_cpu_offset[" + str(cpu) + >> + "]") >> + pointer = var_ptr.cast(get_long_type()) + offset >> + return pointer.cast(var_ptr.type).dereference() >> + >> + >> +class PerCpu(gdb.Function): >> + __doc__ = "Return per-cpu variable.\n" \ >> + "\n" \ >> + "$lx_per_cpu(\"VAR\"[, CPU]): Return the per-cpu variable called VAR for the\n" \ >> + "given CPU number. If CPU is omitted, the CPU of the current context is used.\n" \ >> + "Note that VAR has to be quoted as string." > > > Ok, seriously now: > > apropos shows the "Return per-cpu... " line above. Have you found out > which gdb command shows the rest? help and info both say "Undefined > command". help function lx_... It took me a while to find this, too. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux