Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756833Ab2BNRaE (ORCPT ); Tue, 14 Feb 2012 12:30:04 -0500 Received: from relais.videotron.ca ([24.201.245.36]:21141 "EHLO relais.videotron.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752593Ab2BNRaC (ORCPT ); Tue, 14 Feb 2012 12:30:02 -0500 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN; CHARSET=US-ASCII Date: Tue, 14 Feb 2012 12:30:00 -0500 (EST) From: Nicolas Pitre To: Rabin Vincent Cc: Russell King - ARM Linux , Stephen Boyd , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas Subject: Re: [PATCH] ARM: cache-v7: Disable preemption when reading CCSIDR In-reply-to: <20120214141524.GB3310@debian> Message-id: 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> <20120214141524.GB3310@debian> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3784 Lines: 95 On Tue, 14 Feb 2012, Rabin Vincent wrote: > 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 Reviewed-by: 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/