From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp03.au.ibm.com (e23smtp03.au.ibm.com [202.81.31.145]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp03.au.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 83514B6F01 for ; Fri, 9 Jul 2010 16:17:01 +1000 (EST) Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp03.au.ibm.com (8.14.4/8.13.1) with ESMTP id o696DQA9012018 for ; Fri, 9 Jul 2010 16:13:26 +1000 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o696H1c31478786 for ; Fri, 9 Jul 2010 16:17:01 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o696H0E3011389 for ; Fri, 9 Jul 2010 16:17:00 +1000 From: Benjamin Herrenschmidt To: linuxppc-dev@ozlabs.org Subject: [PATCH 05/13] powerpc/book3e: Don't re-trigger decrementer on lazy irq restore Date: Fri, 9 Jul 2010 16:16:47 +1000 Message-Id: <1278656215-24705-5-git-send-email-benh@kernel.crashing.org> In-Reply-To: <1278656215-24705-4-git-send-email-benh@kernel.crashing.org> References: <1278656215-24705-1-git-send-email-benh@kernel.crashing.org> <1278656215-24705-2-git-send-email-benh@kernel.crashing.org> <1278656215-24705-3-git-send-email-benh@kernel.crashing.org> <1278656215-24705-4-git-send-email-benh@kernel.crashing.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The decrementer on BookE acts as a level interrupt and doesn't need to be re-triggered when going negative. It doesn't go negative anyways (unless programmed to auto-reload with a negative value) as it stops when reaching 0. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/irq.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 77be3d0..fa6f385 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -159,8 +159,17 @@ notrace void raw_local_irq_restore(unsigned long en) * use local_paca instead of get_paca() to avoid preemption checking. */ local_paca->hard_enabled = en; + +#ifndef CONFIG_BOOKE + /* On server, re-trigger the decrementer if it went negative since + * some processors only trigger on edge transitions of the sign bit. + * + * BookE has a level sensitive decrementer (latches in TSR) so we + * don't need that + */ if ((int)mfspr(SPRN_DEC) < 0) mtspr(SPRN_DEC, 1); +#endif /* CONFIG_BOOKE */ /* * Force the delivery of pending soft-disabled interrupts on PS3. -- 1.6.3.3