From owner-freebsd-sparc64@FreeBSD.ORG Tue Feb 14 08:48:03 2006 Return-Path: X-Original-To: freebsd-sparc64@freebsd.org Delivered-To: freebsd-sparc64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A2BE816A420; Tue, 14 Feb 2006 08:48:03 +0000 (GMT) (envelope-from marius@newtrinity.zeist.de) Received: from newtrinity.zeist.de (newtrinity.zeist.de [217.24.217.8]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5133143D55; Tue, 14 Feb 2006 08:47:59 +0000 (GMT) (envelope-from marius@newtrinity.zeist.de) Received: from newtrinity.zeist.de (localhost [127.0.0.1]) by newtrinity.zeist.de (8.12.11/8.12.11/ZEIST.DE) with ESMTP id k1E8lsfZ082414; Tue, 14 Feb 2006 09:47:54 +0100 (CET) (envelope-from marius@newtrinity.zeist.de) Received: (from marius@localhost) by newtrinity.zeist.de (8.12.11/8.12.10/Submit) id k1E8ljCH082413; Tue, 14 Feb 2006 09:47:45 +0100 (CET) (envelope-from marius) Date: Tue, 14 Feb 2006 09:47:44 +0100 From: Marius Strobl To: Antoine Brodin Message-ID: <20060214094744.A81690@newtrinity.zeist.de> References: <200602131150.k1DBo6S1074438@freefall.freebsd.org> <200602131223.51561.jhb@freebsd.org> <20060213193613.547d1b8f.antoine.brodin@laposte.net> <200602131430.11228.jhb@freebsd.org> <20060213213719.7767921e.antoine.brodin@laposte.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20060213213719.7767921e.antoine.brodin@laposte.net>; from antoine.brodin@laposte.net on Mon, Feb 13, 2006 at 09:37:19PM +0100 X-AntiVirus-modified: yes X-AntiVirus: checked by AntiVir Milter (version: 1.1.2-1; AVE: 6.33.0.31; VDF: 6.33.0.232; host: newtrinity.zeist.de) Cc: freebsd-sparc64@freebsd.org Subject: Re: sparc64/93226: DEBUG_LOCKS (really stack_save()) causes panics on sparc64 X-BeenThere: freebsd-sparc64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the Sparc List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Feb 2006 08:48:03 -0000 On Mon, Feb 13, 2006 at 09:37:19PM +0100, Antoine Brodin wrote: > John Baldwin wrote: > > On Monday 13 February 2006 13:36, Antoine Brodin wrote: > > > John Baldwin wrote: > > > > If there are kernel functions before the assembly ones (dependent on link > > > > order) then this would wrongly bail when it hit those. I think you need > > > > to do what the ddb stack tracing code does which is to lookup the symbol > > > > name and do a bcmp() on the first 4 chars to recognize trapframes. > > > > > > I ran objdump -d on a sparc64 kernel and it looks like tl0_* and tl1_* > > > are always at the beginning of the code, there is some kind of magic. > > > > magic aside, it would be best to use the same algorithm in both places IMO. > > It would also be a lot more intuitive to other folks later on. > > There are 2 reasons why I didn't use db_search_symbol() and > db_symbol_values() : > > - first they aren't reentrant, they use a global variable > db_last_symtab and they can panic if a thread sets db_last_symtab to 0 > while another one is using it. I found this in my mail archive : > %%% > Stopped at X_db_symbol_values+0x18: cmpl $0,0xc(%eax) > db> trace > Tracing pid 34983 tid 100093 td 0xc2e9c640 > X_db_symbol_values(0,c0738214,e84859f4,e84859c4,7c) at X_db_symbol_values+0x18 > db_symbol_values(c0738214,e84859f4,0,c89d19c8,0) at db_symbol_values+0x40 > %%% > It can be fixed easily but I don't have the fix anymore. > You can use linker_ddb_search_symbol() and linker_ddb_symbol_values() > too that are safer. > > - the second reason is performance. if you replace > CTRSTACK(KTR_LOCK, &stack, 0, 1); > by > CTRSTACK(KTR_LOCK, &stack, 0, 0); > in kern_lock.c, i.e. if you print the symbol name in the ktr traces, you > will notice that your box is extremely slow. (you type ls, you wait 4 or 5 > seconds and you have the result) > Can't we just use what's done in support.S and add two dummy symbols to mark the begin and end of the asm functions in question? Marius -- This mail was scanned by AntiVir Milter. This product is licensed for non-commercial use. See www.antivir.de for details.