From patchwork Wed Sep 13 16:37:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 13383511 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 B9FC3EE01E0 for ; Wed, 13 Sep 2023 16:39:34 +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:References:In-Reply-To: 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: List-Owner; bh=St+9M3+vBBQLAu15pBiHTDZ+vT+dJJ96JNfrPrq7K0c=; b=mnt1kNttgNDpLD DvaG1Gp5+WsIY/pZwiJmxOwzbilo70U6tiWHAim1MQj8uH4YGqAmL+U3uSizlCqCKij3brQf2+Nw2 Y/gK0pgz6mpa5ZmmKDU3Rd4yWkcBbTkfaTlL3/ouzwM3gUMLP3DUOY+TR9yven0rzowJTfSQXv8dD uVaQZGCXuCeoXYD1Ws7yLfITHETUDSMtMeqYSih2G4/ZQWA3Ccv4qnqAsH2nlSwHcgOsPY5rhq4fk uECWX7rtBJT/3ejyqmK0AcBw3CJoN5zb59aXF4yVHifrARs9BwGeoh+wjeIzONQMbRs5qO5AVjcIq pm2iaaqWSMsI1Haa3i8Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgStm-006LL3-0i; Wed, 13 Sep 2023 16:39:30 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgStS-006Ky4-1c; Wed, 13 Sep 2023 16:39:12 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 43985C15; Wed, 13 Sep 2023 09:39:44 -0700 (PDT) Received: from merodach.members.linode.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4845B3F5A1; Wed, 13 Sep 2023 09:39:05 -0700 (PDT) From: James Morse To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev Cc: x86@kernel.org, Salil Mehta , Russell King , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com Subject: [RFC PATCH v2 07/35] x86: intel_epb: Don't rely on link order Date: Wed, 13 Sep 2023 16:37:55 +0000 Message-Id: <20230913163823.7880-8-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230913163823.7880-1-james.morse@arm.com> References: <20230913163823.7880-1-james.morse@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230913_093910_697679_DB94154C X-CRM114-Status: GOOD ( 10.84 ) X-BeenThere: linux-riscv@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-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org intel_epb_init() is called as a subsys_initcall() to register cpuhp callbacks. The callbacks make use of get_cpu_device() which will return NULL unless register_cpu() has been called. register_cpu() is called from topology_init(), which is also a subsys_initcall(). This is fragile. Moving the register_cpu() to a different subsys_initcall() leads to a NULL derefernce during boot. Make intel_epb_init() a late_initcall(), user-space can't provide a policy before this point anyway. Signed-off-by: James Morse --- subsys_initcall_sync() would be an option, but moving the register_cpu() calls into ACPI also means adding a safety net for CPUs that are online but not described properly by firmware. This lives in subsys_initcall_sync(). --- arch/x86/kernel/cpu/intel_epb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/intel_epb.c b/arch/x86/kernel/cpu/intel_epb.c index e4c3ba91321c..f18d35fe27a9 100644 --- a/arch/x86/kernel/cpu/intel_epb.c +++ b/arch/x86/kernel/cpu/intel_epb.c @@ -237,4 +237,4 @@ static __init int intel_epb_init(void) cpuhp_remove_state(CPUHP_AP_X86_INTEL_EPB_ONLINE); return ret; } -subsys_initcall(intel_epb_init); +late_initcall(intel_epb_init);