From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5017 invoked by alias); 26 Oct 2007 01:52:37 -0000 Received: (qmail 4973 invoked by uid 22791); 26 Oct 2007 01:52:29 -0000 X-Spam-Check-By: sourceware.org Received: from gate.crashing.org (HELO gate.crashing.org) (63.228.1.57) by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 26 Oct 2007 01:52:28 +0000 Received: from [127.0.0.1] (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.13.8/8.13.8) with ESMTP id l9Q1qCGD001443; Thu, 25 Oct 2007 20:52:13 -0500 Subject: Re: Apparent kernel bug with GDB on ppc405 From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: David Daney Cc: Matt Mackall , gdb@sourceware.org, linuxppc-embedded@ozlabs.org In-Reply-To: <471FAC48.1070008@avtrex.com> References: <20071024194640.GB19691@waste.org> <471FAC48.1070008@avtrex.com> Content-Type: text/plain Date: Fri, 26 Oct 2007 01:52:00 -0000 Message-Id: <1193363530.7018.42.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit 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/msg00253.txt.bz2 On Wed, 2007-10-24 at 13:34 -0700, David Daney wrote: > First of all I have never used a similar configuration so this may be > totally off base. But... > > If the icache is virtually indexed, then I think there are only two > ways > to invalidate it. The first is from the context of the debugged > process > where the page is mapped at the location the target program will see > it. > If you try to invalidate from the context of the debugger, the > page > will most likely not be mapped at the virtual address of the target > program so you might have to invalidate the *entire* icache. Yup, sounds likely. We don't handle that virtual icache well at all in linux. Things tend to work by mere luck. I have various ideas to fix that but haven't actually implemented them. Ben.