From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965161AbaFCXBz (ORCPT ); Tue, 3 Jun 2014 19:01:55 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.232]:45985 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S964824AbaFCXBx (ORCPT ); Tue, 3 Jun 2014 19:01:53 -0400 Date: Tue, 3 Jun 2014 19:01:51 -0400 From: Steven Rostedt To: Petr Mladek Cc: Frederic Weisbecker , Masami Hiramatsu , Jiri Kosina , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH] ftrace/x86: Call text_ip_addr() instead of the duplicated code Message-ID: <20140603190151.0f8e2087@gandalf.local.home> In-Reply-To: <1401812601-2359-1-git-send-email-pmladek@suse.cz> References: <1401812601-2359-1-git-send-email-pmladek@suse.cz> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 3 Jun 2014 18:23:21 +0200 Petr Mladek wrote: > I just went over this when looking at some Xen-related ftrace initialization > problems. They were related to Xen code that is not upstream but this clean up > would make sense here. > > I think that this was already the intention when text_ip_addr() was introduced > in the commit 87fbb2ac6073a703930 (ftrace/x86: Use breakpoints for converting > function graph caller). Anyway, better do it now before it shots people into > their leg ;-) You know, I made this change. It somehow got lost :-/ I better analyze this a bit to make sure it was just lost and I didn't find some odd ball reason not to apply it. But I doubt I'll find anything. If not, I'll get it enqueued for 3.16. Thanks! -- Steve > > Signed-off-by: Petr Mladek > --- > arch/x86/kernel/ftrace.c | 11 +---------- > 1 file changed, 1 insertion(+), 10 deletions(-) > > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > index 89de3eaf8772..cbc4a91b131e 100644 > --- a/arch/x86/kernel/ftrace.c > +++ b/arch/x86/kernel/ftrace.c > @@ -297,16 +297,7 @@ int ftrace_int3_handler(struct pt_regs *regs) > > static int ftrace_write(unsigned long ip, const char *val, int size) > { > - /* > - * On x86_64, kernel text mappings are mapped read-only with > - * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead > - * of the kernel text mapping to modify the kernel text. > - * > - * For 32bit kernels, these mappings are same and we can use > - * kernel identity mapping to modify code. > - */ > - if (within(ip, (unsigned long)_text, (unsigned long)_etext)) > - ip = (unsigned long)__va(__pa_symbol(ip)); > + ip = text_ip_addr(ip); > > if (probe_kernel_write((void *)ip, val, size)) > return -EPERM;