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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 CA6DACA9EB9 for ; Mon, 21 Oct 2019 18:08:08 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A2C272086D for ; Mon, 21 Oct 2019 18:08:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nC55oCgG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2C272086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=IyQodRenIsRV+TbtoCrCIOBgQU5tpP1nVN+s+xSkoIs=; b=nC55oCgGodCDOM eOiN1DLrwxwBmZvUghcxE12h+DqDaXxPu8xEuAyI0N3id6ZFUbZSxJQxpcWQgg5dJPaj5dpdArE82 ArDp/s63pGUOVQ30iwp9ApNQQLJb8WdDAB6tWXUXQfdCgfaoawcMg5BigfSro8utObcMJeV8yGGYF C0AU9rl8PKy6E945Z4vy9/Kbt2R3jKrEXna5AG+83Bs0lv4eQG3mcE2lbbgjjoIpZYX20rEJJcf/4 gSdG0LCZx2qAxAqhU3c3v2mhd5VwjAyGPwyhTuYY37vh7Gz9z4doe+oB/P0DD+idzF1eGe2neYJXF iosFxUUCg+VdCP/obbeQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iMc66-0007No-St; Mon, 21 Oct 2019 18:08:02 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iMc63-0007N9-JR for linux-arm-kernel@lists.infradead.org; Mon, 21 Oct 2019 18:08:01 +0000 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ADE8B2086D; Mon, 21 Oct 2019 18:07:57 +0000 (UTC) Date: Mon, 21 Oct 2019 14:07:56 -0400 From: Steven Rostedt To: Mark Rutland Subject: Re: [PATCH 1/8] ftrace: add ftrace_init_nop() Message-ID: <20191021140756.613a1bac@gandalf.local.home> In-Reply-To: <20191021163426.9408-2-mark.rutland@arm.com> References: <20191021163426.9408-1-mark.rutland@arm.com> <20191021163426.9408-2-mark.rutland@arm.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191021_110759_704964_9ECF1B5B X-CRM114-Status: GOOD ( 22.26 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jthierry@redhat.com, will@kernel.org, ard.biesheuvel@linaro.org, peterz@infradead.org, catalin.marinas@arm.com, deller@gmx.de, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, takahiro.akashi@linaro.org, mingo@redhat.com, james.morse@arm.com, jeyu@kernel.org, amit.kachhap@arm.com, svens@stackframe.org, duwe@suse.de, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 21 Oct 2019 17:34:19 +0100 Mark Rutland wrote: > Architectures may need to perform special initialization of ftrace > callsites, and today they do so by special-casing ftrace_make_nop() when > the expected branch address is MCOUNT_ADDR. In some cases (e.g. for > patchable-function-entry), we don't have an mcount-like symbol and don't > want a synthetic MCOUNT_ADDR, but we may need to perform some > initialization of callsites. > > To make it possible to separate initialization from runtime > modification, and to handle cases without an mcount-like symbol, this > patch adds an optional ftrace_init_nop() function that architectures can > implement, which does not pass a branch address. > > Where an architecture does not provide ftrace_init_nop(), we will fall > back to the existing behaviour of calling ftrace_make_nop() with > MCOUNT_ADDR. > > At the same time, ftrace_code_disable() is renamed to > ftrace_code_init_disabled() to make it clearer that it is intended to > intialize a callsite into a disabled state, and is not for disabling a > callsite that has been runtime enabled. To make the name even better, let's just rename it to: ftrace_nop_initialization() I think that may be the best description for it. > > Signed-off-by: Mark Rutland > Cc: Ingo Molnar > Cc: Steven Rostedt > Cc: Torsten Duwe > --- > kernel/trace/ftrace.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index f296d89be757..afd7e210e595 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -2493,15 +2493,22 @@ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) > return &iter->pg->records[iter->index]; > } > > +#ifndef ftrace_init_nop > +static int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) > +{ > + return ftrace_make_nop(mod, rec, MCOUNT_ADDR); > +} > +#endif Can you place the above in the ftrace.h header. That's where that would belong. #ifndef ftrace_init_nop struct module; static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return ftrace_make_nop(mod, rec, MCOUNT_ADDR); } #endif -- Steve > + > static int > -ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) > +ftrace_code_init_disabled(struct module *mod, struct dyn_ftrace *rec) > { > int ret; > > if (unlikely(ftrace_disabled)) > return 0; > > - ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); > + ret = ftrace_init_nop(mod, rec); > if (ret) { > ftrace_bug_type = FTRACE_BUG_INIT; > ftrace_bug(ret, rec); > @@ -2943,7 +2950,7 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) > * to the NOP instructions. > */ > if (!__is_defined(CC_USING_NOP_MCOUNT) && > - !ftrace_code_disable(mod, p)) > + !ftrace_code_init_disabled(mod, p)) > break; > > update_cnt++; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel