Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760187Ab2BNOXd (ORCPT ); Tue, 14 Feb 2012 09:23:33 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:34290 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756274Ab2BNOXc (ORCPT ); Tue, 14 Feb 2012 09:23:32 -0500 Date: Tue, 14 Feb 2012 19:45:24 +0530 From: Rabin Vincent To: Russell King - ARM Linux Cc: Stephen Boyd , Nicolas Pitre , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas Subject: Re: [PATCH] ARM: cache-v7: Disable preemption when reading CCSIDR Message-ID: <20120214141524.GB3310@debian> References: <1328234629-32735-1-git-send-email-sboyd@codeaurora.org> <4F3952C7.3040502@codeaurora.org> <20120213181501.GD25655@n2100.arm.linux.org.uk> <4F398D61.9080501@codeaurora.org> <20120213232901.GG25655@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120213232901.GG25655@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3523 Lines: 89 On Mon, Feb 13, 2012 at 11:29:01PM +0000, Russell King - ARM Linux wrote: > On Mon, Feb 13, 2012 at 02:23:29PM -0800, Stephen Boyd wrote: > > On 02/13/12 10:15, Russell King - ARM Linux wrote: > > > On Mon, Feb 13, 2012 at 10:13:27AM -0800, Stephen Boyd wrote: > > >> Thanks. Russell has already merged the original patch to the fixes > > >> branch. Hopefully he can fold this one in. > > > Nope, I've asked Linus to pull it. > > > > > > So do we conclude that the original patch wasn't properly tested? :P > > > > Sigh. Lockdep strikes again! I promise I tested it with lockdep disabled. > > > > It looks like Linus' hasn't pulled yet but maybe he just hasn't > > published it. > > It's not nice to change something after you've sent a pull request - > there's no way of knowing when Linus actually pulls it before he's > published it, and if he gets something different then it can raise > questions. > > So, it's gone in as-is, and, as I'm now intending asking for another > pull request soo soon after my previous one, this is something that > we will have to live with probably for the remainder of the week. OK, since it can't be folded in, here is a proper patch: 8<--------- >From 26f02624a20a61ed1997a4e8648e4c766a54d91d Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Tue, 14 Feb 2012 19:22:07 +0530 Subject: [PATCH] ARM: fix v7 boot with lockdep enabled Bootup with lockdep enabled has been broken on v7 since b46c0f74657d ("ARM: 7321/1: cache-v7: Disable preemption when reading CCSIDR"). This is because v7_setup (which is called very early during boot) calls v7_flush_dcache_all, and the save_and_disable_irqs added by that patch ends up attempting to call into lockdep C code (trace_hardirqs_off()) when we are in no position to execute it (no stack, MMU off). Fix this by using a notrace variant of save_and_disable_irqs. The code already uses the notrace variant of restore_irqs. Cc: Stephen Boyd Cc: Catalin Marinas Cc: Nicolas Pitre Cc: stable@vger.kernel.org Signed-off-by: Rabin Vincent --- arch/arm/include/asm/assembler.h | 5 +++++ arch/arm/mm/cache-v7.S | 2 +- 2 files changed, 6 insertions(+), 1 deletions(-) diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 62f8095..23371b1 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -137,6 +137,11 @@ disable_irq .endm + .macro save_and_disable_irqs_notrace, oldcpsr + mrs \oldcpsr, cpsr + disable_irq_notrace + .endm + /* * Restore interrupt state previously stored in a register. We don't * guarantee that this will preserve the flags. diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S index 7a24d396..a655d3d 100644 --- a/arch/arm/mm/cache-v7.S +++ b/arch/arm/mm/cache-v7.S @@ -55,7 +55,7 @@ loop1: cmp r1, #2 @ see what cache we have at this level blt skip @ skip if no cache, or just i-cache #ifdef CONFIG_PREEMPT - save_and_disable_irqs r9 @ make cssr&csidr read atomic + save_and_disable_irqs_notrace r9 @ make cssr&csidr read atomic #endif mcr p15, 2, r10, c0, c0, 0 @ select current cache level in cssr isb @ isb to sych the new cssr&csidr -- 1.7.9 -- 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/