From owner-freebsd-arm@FreeBSD.ORG Sat Aug 3 07:42:46 2013 Return-Path: Delivered-To: freebsd-arm@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 5D690834; Sat, 3 Aug 2013 07:42:46 +0000 (UTC) (envelope-from andrew@fubar.geek.nz) Received: from nibbler.fubar.geek.nz (nibbler.fubar.geek.nz [199.48.134.198]) by mx1.freebsd.org (Postfix) with ESMTP id 3CF7C2A88; Sat, 3 Aug 2013 07:42:46 +0000 (UTC) Received: from bender.Home (97e5e46b.skybroadband.com [151.229.228.107]) by nibbler.fubar.geek.nz (Postfix) with ESMTPSA id 5DD165E200; Sat, 3 Aug 2013 07:32:55 +0000 (UTC) Date: Sat, 3 Aug 2013 08:32:48 +0100 From: Andrew Turner To: Ian Lepore Subject: Re: Kernel Panic on DREAMPLUG: Alignment Fault 1 Message-ID: <20130803083248.342108c2@bender.Home> In-Reply-To: <1375374521.45247.211.camel@revolution.hippie.lan> References: <51F92F79.9010809@gmail.com> <1375309907.45247.185.camel@revolution.hippie.lan> <51F9C81A.7000106@gmail.com> <1375358623.45247.189.camel@revolution.hippie.lan> <51FA1D2B.9090009@gmail.com> <1375363713.45247.193.camel@revolution.hippie.lan> <51FA8946.8030301@gmail.com> <1375374521.45247.211.camel@revolution.hippie.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-arm@FreeBSD.org, mattia.rossi.mate@gmail.com X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 03 Aug 2013 07:42:46 -0000 On Thu, 01 Aug 2013 10:28:41 -0600 Ian Lepore wrote: > On Thu, 2013-08-01 at 18:13 +0200, Mattia Rossi wrote: > > On 01/08/13 15:28, Ian Lepore wrote: > > > On Thu, 2013-08-01 at 10:32 +0200, Mattia Rossi wrote: > > >> > > >> > > >> Anyhow, I'll try to compile with gcc, and see what happens. > > > The host system's compiler (gcc in your case) is used to build the > > > selected compiler from src/, then that new compiler is used to > > > build the rest of src/ into a runnable system. You can define > > > WITHOUT_CLANG_IS_CC and WITHOUT_EABI to use gcc, and you should > > > probably add WITHOUT_CLANG to avoid building it since it won't be > > > used (and it takes forever to build). > > Kernel built with gcc: > > [snip... same fault as with clang] > > Yep, I just had the same experience -- same fault, same place, > addresses differ by a few bytes which is to be expected with a > different compiler. > > I've just confirmed that gcc and WITHOUT_ARM_EABI=yes works fine, so > the problem seems to be that we're somehow not maintaining stack > alignment correctly for EABI on architectures prior to armv6. I have > a feeling somewhere in the code is something conditional on ARMV6 > that really needs to include armv5te (which has the ldrd/strd > instructions). Can you try the patch at [1]. It should fix the stack alignment in exceptions. I suspect gcc is working in this case because it doesn't generate any instructions that rely on the stack alignment, where clang does. Andrew [1] http://people.freebsd.org/~andrew/trapframe_align2.diff