Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756150AbaDXVsl (ORCPT ); Thu, 24 Apr 2014 17:48:41 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39763 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755599AbaDXVqS (ORCPT ); Thu, 24 Apr 2014 17:46:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Fabio M. Di Nitto" , Jan Engelhardt , "David S. Miller" Subject: [PATCH 3.10 21/23] sparc64: Make sure %pil interrupts are enabled during hypervisor yield. Date: Thu, 24 Apr 2014 14:48:51 -0700 Message-Id: <20140424214828.619144912@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140424214825.933835556@linuxfoundation.org> References: <20140424214825.933835556@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: "David S. Miller" [ Upstream commit cb3042d609e30e6144024801c89be3925106752b ] In arch_cpu_idle() we must enable %pil based interrupts before potentially invoking the hypervisor cpu yield call. As per the Hypervisor API documentation for cpu_yield: Interrupts which are blocked by some mechanism other that pstate.ie (for example %pil) are not guaranteed to cause a return from this service. It seems that only first generation Niagara chips are hit by this bug. My best guess is that later chips implement this in hardware and wake up anyways from %pil events, whereas in first generation chips the yield is implemented completely in hypervisor code and requires %pil to be enabled in order to wake properly from this call. Fixes: 87fa05aeb3a5 ("sparc: Use generic idle loop") Reported-by: Fabio M. Di Nitto Reported-by: Jan Engelhardt Tested-by: Jan Engelhardt Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/sparc/kernel/process_64.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -57,9 +57,12 @@ void arch_cpu_idle(void) { if (tlb_type != hypervisor) { touch_nmi_watchdog(); + local_irq_enable(); } else { unsigned long pstate; + local_irq_enable(); + /* The sun4v sleeping code requires that we have PSTATE.IE cleared over * the cpu sleep hypervisor call. */ @@ -81,7 +84,6 @@ void arch_cpu_idle(void) : "=&r" (pstate) : "i" (PSTATE_IE)); } - local_irq_enable(); } #ifdef CONFIG_HOTPLUG_CPU -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/