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 A322CC3DA7D for ; Thu, 5 Jan 2023 09:09:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232005AbjAEJJP (ORCPT ); Thu, 5 Jan 2023 04:09:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231596AbjAEJIm (ORCPT ); Thu, 5 Jan 2023 04:08:42 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D55114028 for ; Thu, 5 Jan 2023 01:08:41 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BCE07618DC for ; Thu, 5 Jan 2023 09:08:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A282C433EF; Thu, 5 Jan 2023 09:08:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1672909720; bh=dC2abtwgmwdN1tfArHQUKSGHFcouBA0RhxdxCoHf14o=; h=From:To:Cc:Subject:Date:From; b=o21dzTZ8EJP4ZuoTkTP617ILWOb9XMeQlZNs8yWVhxbzasyhgB+0x1FNEmdnaqgU/ KvohIPPBA1YXYZf+H24bytpa6uOxCsuHXr2m5nH/9V6iZ3biojC+ZseY82OiT7RJ32 87FCXPAGclmnok+JmMBJ6FHmDGI6jCtlx9K1dIHlezT8iekr5KT6u8QECfYAj2cNcH PD05JJ6Fbxk+KPVo2yQHMAbKuV970X5dBgTflH0JYxIWcpDxUztBYGnt/xpcTBi4yv lOJRLj+OcFT0mQhEFetAaXTj9dexmddS9MMdH8LGMfGipIn015AqHkznBBnxEY+NPu oJrNycyIXhoIw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pDMEn-00Gx2C-Tn; Thu, 05 Jan 2023 09:08:37 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Hector Martin , Dmitry Baryshkov , Mark Brown , Ulf Hansson , Arnd Bergmann , Mark Rutland , Lorenzo Pieralisi Subject: [PATCH] firmware/psci: Don't register with debugfs if PSCI isn't available Date: Thu, 5 Jan 2023 09:08:34 +0000 Message-Id: <20230105090834.630238-1-maz@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, marcan@marcan.st, dmitry.baryshkov@linaro.org, broonie@kernel.org, ulf.hansson@linaro.org, arnd@arndb.de, mark.rutland@arm.com, lpieralisi@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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)); } -- 2.34.1