From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B8EDC43331 for ; Mon, 11 Nov 2019 17:20:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BE8E20656 for ; Mon, 11 Nov 2019 17:20:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="r2tbYsVK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727050AbfKKRUc (ORCPT ); Mon, 11 Nov 2019 12:20:32 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:47980 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726845AbfKKRUb (ORCPT ); Mon, 11 Nov 2019 12:20:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3BImvdb2SjGg8FjjNsGxYBZHiJBQpDDVPvVag5XpsOE=; b=r2tbYsVKwZIBwdlDgP2eTSjCn pu8VDDf2gMnj8yMwXNGYiA6rmXhMNS6ntXgudtDU5KYpGhvU5BNxwpRNra0BLXXijHVKRGEy0eAZs 2nRhMJxJAPQ12q1BBW22S4y6jSG1JSlbzUcZvyUC4oS5Cy6UR1OLN9kwsUIdIoBZaiTav0iNU7emJ 7AEzD5fZgKtp/DEPmLvKmKi7G/JrXIh362rnqwhqqZqh1rGWLCY/dpM68AWA/x6L0PZDu7hxtvh6s mfgfDmObvaa38xcDubCR488ESw4i18FOmt0gzl4C6RL8Op+W+fZiQQGgMZ62m8aQweW7ewGnCiQ5r BkjU2Zx8w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iUDM6-0004mb-IG; Mon, 11 Nov 2019 17:19:58 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 639CD3056BE; Mon, 11 Nov 2019 18:18:49 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C28C120302EF3; Mon, 11 Nov 2019 18:19:55 +0100 (CET) Date: Mon, 11 Nov 2019 18:19:55 +0100 From: Peter Zijlstra To: Will Deacon Cc: x86@kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, jeyu@kernel.org, alexei.starovoitov@gmail.com, rabin@rab.in, Mark Rutland , james.morse@arm.com Subject: Re: [PATCH -v5 13/17] arm/ftrace: Use __patch_text_real() Message-ID: <20191111171955.GO4114@hirez.programming.kicks-ass.net> References: <20191111131252.921588318@infradead.org> <20191111132458.220458362@infradead.org> <20191111164703.GA11521@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191111164703.GA11521@willie-the-truck> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 11, 2019 at 04:47:03PM +0000, Will Deacon wrote: > I'd still prefer to pass 'true' unconditionally here, since I don't think > this is a hot path. If you can give me a Tested-by, I'll replace it with the below... :-) --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -22,6 +22,7 @@ #include #include #include +#include #ifdef CONFIG_THUMB2_KERNEL #define NOP 0xf85deb04 /* pop.w {lr} */ @@ -35,9 +36,7 @@ static int __ftrace_modify_code(void *da { int *command = data; - set_kernel_text_rw(); ftrace_modify_all_code(*command); - set_kernel_text_ro(); return 0; } @@ -59,13 +58,11 @@ static unsigned long adjust_address(stru int ftrace_arch_code_modify_prepare(void) { - set_all_modules_text_rw(); return 0; } int ftrace_arch_code_modify_post_process(void) { - set_all_modules_text_ro(); /* Make sure any TLB misses during machine stop are cleared. */ flush_tlb_all(); return 0; @@ -97,10 +94,7 @@ static int ftrace_modify_code(unsigned l return -EINVAL; } - if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE)) - return -EPERM; - - flush_icache_range(pc, pc + MCOUNT_INSN_SIZE); + __patch_text_real((void *)pc, new, true); return 0; }