From patchwork Thu Jan 5 09:08:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13090401 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6E0A0C3DA7A for ; Thu, 5 Jan 2023 19:46:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=wJzYxOZ21Ka3D3Dps19JLAFYsPh/W85gov/0mYAbBEY=; b=DET9CidGuAlbXj go5PuKQOArczC6jfL2nx9SXiP8KKX7+NMt8kPRD6zitWhrzz1kA/bU7dsIpKwxss1xlrXi43M7l2X JCwQmx2kB6yuCgBtXF3b+lqtC37ARJRuREnEOPAkwp/6JbBSzDPry/NcuBYO1Upm6wGcbDHM+fqn5 KHs29uiV2izRdr25XUyD16IBiveJoXqsB9yv1CuD7Cqy9O2TFhO4aGSabv4X2VvV9WoWpTQ/DUYMw HGpdRqVbcbhk9n6cz3IkqBZhHiU7LaZymkeTw/nnAfySSUivB9TBbiCgc+GLfYOJBp0m0Vq/pWGIn wYX2Fj0w4VBGhxaFCvZg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pDWB7-00EE2c-69; Thu, 05 Jan 2023 19:45:29 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pDMEs-009H46-No for linux-arm-kernel@lists.infradead.org; Thu, 05 Jan 2023 09:08:44 +0000 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 ams.source.kernel.org (Postfix) with ESMTPS id 6547FB80D75; Thu, 5 Jan 2023 09:08:41 +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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230105_010843_000655_42033BB9 X-CRM114-Status: GOOD ( 15.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 Acked-by: Mark Rutland Acked-by: Dmitry Baryshkov Reviewed-by: Hector Martin --- 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)); }