From patchwork Tue Nov 7 10:29:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Russell King \(Oracle\)" X-Patchwork-Id: 742175 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 2B6FDC0018C for ; Tue, 7 Nov 2023 10:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233938AbjKGK3s (ORCPT ); Tue, 7 Nov 2023 05:29:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233850AbjKGK3r (ORCPT ); Tue, 7 Nov 2023 05:29:47 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17F4012C; Tue, 7 Nov 2023 02:29:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Date:Sender:Message-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References: In-Reply-To:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=+gACgpTQj8OpvruPj/p3shExXAIg9qVB65uOYbGxgdU=; b=KqJga0cJkf0ea2I44dro/hehY+ hdGHrWJf9SO9FdCGw+AG9MFvt/hy1EM8laesvxJR3tlIJm04unhSe1TyMvk5EOkVpAVmnQEzEGvk2 erEqCrnXjQNiZHzYYZxVVhyVh7jBOTkO5gRjjijQwz8tW3XZQPsB1UeV4/h/eZcKG86V0Hz8ev82u xdr3rDxe/M5yjtU8f98kyXf+5wrQ8fSNhMKHgI8hgzksRtWxYcmdC1WQdfIj4RfgFB3Dh5PyS4lKJ OOd1sULTW/XN1dkdCIkVRG8j5hzT0k/nvc0vkOLSQ3xApjwWJrgOiQMzmMmP6FLoc0jLsOWEoyIsS XcI5Shxw==; Received: from e0022681537dd.dyn.armlinux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:54700 helo=rmk-PC.armlinux.org.uk) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1r0JKo-0000Dk-39; Tue, 07 Nov 2023 10:29:27 +0000 Received: from rmk by rmk-PC.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1r0JKq-00CTwZ-Mh; Tue, 07 Nov 2023 10:29:28 +0000 In-Reply-To: References: From: Russell King (Oracle) 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, x86@kernel.org, linux-csky@vger.kernel.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org Cc: Salil Mehta , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com, James Morse , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH RFC 02/22] x86: intel_epb: Don't rely on link order MIME-Version: 1.0 Content-Disposition: inline Message-Id: Sender: Russell King Date: Tue, 07 Nov 2023 10:29:28 +0000 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: James Morse 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 dereference 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 Signed-off-by: Russell King (Oracle) Reviewed-by: Gavin Shan Reviewed-by: Jonathan Cameron --- 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);