From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15727 invoked by alias); 24 Oct 2007 21:54:42 -0000 Received: (qmail 15715 invoked by uid 22791); 24 Oct 2007 21:54:42 -0000 X-Spam-Check-By: sourceware.org Received: from waste.org (HELO waste.org) (66.93.16.53) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 24 Oct 2007 21:54:39 +0000 Received: from waste.org (localhost [127.0.0.1]) by waste.org (8.13.8/8.13.8/Debian-3) with ESMTP id l9OLsN5n001471 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 24 Oct 2007 16:54:23 -0500 Received: (from oxymoron@localhost) by waste.org (8.13.8/8.13.8/Submit) id l9OLsM6E001469; Wed, 24 Oct 2007 16:54:22 -0500 Date: Wed, 24 Oct 2007 21:54:00 -0000 From: Matt Mackall To: Grant Likely Cc: linuxppc-embedded@ozlabs.org, gdb@sourceware.org Subject: Re: Apparent kernel bug with GDB on ppc405 Message-ID: <20071024215421.GF19691@waste.org> References: <20071024194640.GB19691@waste.org> <20071024204215.GC19691@waste.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071024204215.GC19691@waste.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2007-10/txt/msg00212.txt.bz2 On Wed, Oct 24, 2007 at 03:42:16PM -0500, Matt Mackall wrote: > On Wed, Oct 24, 2007 at 02:28:14PM -0600, Grant Likely wrote: > > On 10/24/07, Matt Mackall wrote: > > > I'm trying to debug a trivial statically-linked hello world program on > > > a Xilinx PPC 405 and I'm seeing the following behavior: > > > > > > > > > > > Any suggestions? > > > > http://thread.gmane.org/gmane.linux.ports.ppc.embedded/11202 > > > > I was fighting with a similar problem almost 2 years ago. Looks like > > it might be related. At some point the problem seemed to go away and > > I determined what the root cause was. :-( > > > > I haven't been using gdb lately, so I don't know if it's the same > > problem. Nobody I had talked to had seen the issue on other 405 > > platforms. It could very well be something virtex-specific. > > Could be the same problem, but I'm seeing only your symptom 3 so far. > > I've tried throwing some larger hammers at the problem. Flushing all > of the dcache and icache (flush_dcache_all and > flush_instruction_cache) isn't helping. But printk(".") does! Well there was one remaining cache - the TLB. This patch seems to make things work, but don't ask me why: --- include/asm-ppc/cacheflush.h (revision 10439) +++ include/asm-ppc/cacheflush.h (working copy) @@ -11,6 +11,7 @@ #define _PPC_CACHEFLUSH_H #include +#include /* * No cache flushing is required when address mappings are @@ -35,10 +36,23 @@ extern void flush_icache_user_range(struct vm_area_struct *vma, struct page *page, unsigned long addr, int len); #define copy_to_user_page(vma, page, vaddr, dst, src, len) \ do { memcpy(dst, src, len); \ flush_icache_user_range(vma, page, vaddr, len); \ + _tlbia(); \ } while (0) -- Mathematics is the supreme nostalgia of our time.