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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57266C53210 for ; Thu, 5 Jan 2023 22:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236329AbjAEW4r (ORCPT ); Thu, 5 Jan 2023 17:56:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235935AbjAEW40 (ORCPT ); Thu, 5 Jan 2023 17:56:26 -0500 Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DF7F4FCE7 for ; Thu, 5 Jan 2023 14:56:24 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: marcan@marcan.st) by mail.marcansoft.com (Postfix) with ESMTPSA id D8F0F42137; Thu, 5 Jan 2023 22:56:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=marcan.st; s=default; t=1672959382; bh=04ixmJd54VU6rvGpT6Imyb3wvOAYUE4X1LMn+1eXZPc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=f/E8UEJi76LAG3Psbqv77jbAAMG6z6546+StPcFc6oG/iVXmCDT/MtW11b7htLBKH J1yL1OcegqP/Yn6ZxtJMdRNuUoTJM2+lH/vCHucaouKuYOh74swbRo0B/u8jDmhml7 n8rebT2SzjKgf0e9cjZz2E4aeBUIjYM3vhbMhSstwE4Q77Q7Fa9GVtj+g0Fy9GVtV7 tSLtS0bo7CNIojiMcuPmQBoSFZKz/HSmQjv3eSn9Myqz28SBXFCzUzlKRGn7Y0Ni7X yIZ7i6CJFiR8NZGpnfnUoQdVgqYsO/HEjHk54wA3WuREZYWMX3hNZja9xxqFjMNwo+ Mmzzw0V3QwRDw== Message-ID: <1c670eb4-ad5b-94ea-1892-64a66fa0bae0@marcan.st> Date: Fri, 6 Jan 2023 07:56:17 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available Content-Language: en-US To: Marc Zyngier , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Dmitry Baryshkov , Mark Brown , Ulf Hansson , Arnd Bergmann , Mark Rutland , Lorenzo Pieralisi References: <20230105090834.630238-1-maz@kernel.org> From: Hector Martin In-Reply-To: <20230105090834.630238-1-maz@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/01/2023 18.08, Marc Zyngier wrote: > Contrary to popular belief, PSCI is not a universal property of an > ARM/arm64 system. There is a garden variety of systems out there > that don't (or even cannot) implement it. > > I'm the first one deplore such a situation, but hey... > > On such systems, a "cat /sys/kernel/debug/psci" results in > fireworks, as no invocation callback is registered. > > Check for the invoke_psci_fn and psci_ops.get_version pointers > before registering with the debugfs subsystem, avoiding the > issue altogether. > > Fixes: 3137f2e60098 ("firmware/psci: Add debugfs support to ease debugging") > Reported-by: Hector Martin > Signed-off-by: Marc Zyngier > Cc: Dmitry Baryshkov > Cc: Mark Brown > Cc: Ulf Hansson > Cc: Arnd Bergmann > Cc: Mark Rutland > Cc: Lorenzo Pieralisi > --- > drivers/firmware/psci/psci.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c > index e7bcfca4159f..447ee4ea5c90 100644 > --- a/drivers/firmware/psci/psci.c > +++ b/drivers/firmware/psci/psci.c > @@ -440,6 +440,9 @@ static const struct file_operations psci_debugfs_ops = { > > static int __init psci_debugfs_init(void) > { > + if (!invoke_psci_fn || !psci_ops.get_version) > + return 0; > + > return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL, > &psci_debugfs_ops)); > } Reviewed-by: Hector Martin - Hector