From patchwork Thu Jun 9 20:08:44 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geoff Levand X-Patchwork-Id: 9167857 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 27A5960573 for ; Thu, 9 Jun 2016 20:13:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 17E9428047 for ; Thu, 9 Jun 2016 20:13:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0B5542835F; Thu, 9 Jun 2016 20:13:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B1A3228047 for ; Thu, 9 Jun 2016 20:13:41 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1bB6J4-0007Fp-Ql; Thu, 09 Jun 2016 20:11:58 +0000 Received: from merlin.infradead.org ([2001:4978:20e::2]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1bB6G3-0002ac-RS; Thu, 09 Jun 2016 20:08:51 +0000 Received: from geoff by merlin.infradead.org with local (Exim 4.85_2 #1 (Red Hat Linux)) id 1bB6Fw-00046G-Ea; Thu, 09 Jun 2016 20:08:44 +0000 Message-Id: <194f9fd51174555c41472015a48f54e452c44cc3.1465502767.git.geoff@infradead.org> In-Reply-To: References: From: Geoff Levand Patch-Date: Wed, 1 Jun 2016 11:59:54 -0700 Subject: [PATCH v18 02/13] arm64: Add cpus_are_stuck_in_kernel To: Catalin Marinas , Will Deacon Date: Thu, 09 Jun 2016 20:08:44 +0000 X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , marc.zyngier@arm.com, kexec@lists.infradead.org, AKASHI Takahiro , James Morse , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: James Morse kernel/smp.c has a fancy counter that keeps track of the number of CPUs it marked as not-present and left in cpu_park_loop(). If there are any CPUs spinning in here, kexec will release them once the memory is re-used by the new kernel. Provide a function to expose whether this counter is non-zero, so we can use this when loading a new kexec image, and when calling machine_kexec(). Signed-off-by: James Morse [Split off from a larger patch] Signed-off-by: Geoff Levand --- arch/arm64/include/asm/smp.h | 10 ++++++++++ arch/arm64/kernel/smp.c | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 433e504..38712f4 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -124,6 +124,16 @@ static inline void cpu_panic_kernel(void) cpu_park_loop(); } +/* + * If a secondary CPU fails to come online, (e.g. due to mismatched features), + * it will try to call cpu_die(). If this fails, it updates + * cpus_stuck_in_kernel and sits in cpu_park_loop(). + * + * Kexec checks this counter and refuses to load/kexec if it is non-zero, as + * cpu_park_loop() would be overwritten releasing the parked cpus. + */ +bool cpus_are_stuck_in_kernel(void); + #endif /* ifndef __ASSEMBLY__ */ #endif /* ifndef __ASM_SMP_H */ diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 678e084..d0bcd55 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -909,3 +909,8 @@ int setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } + +bool cpus_are_stuck_in_kernel(void) +{ + return !!cpus_stuck_in_kernel; +}