Message-ID: <4050EDEE.6050706@mvista.com>
Date: Thu, 11 Mar 2004 14:53:34 -0800
From: George Anzinger <george@mvista.com>
Organization: MontaVista Software
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To: Tom Rini <trini@kernel.crashing.org>
CC: "Amit S. Kale" <amitkale@emsyssoft.com>, Pavel Machek <pavel@ucw.cz>,
       Kernel Mailing List <linux-kernel@vger.kernel.org>,
       kgdb-bugreport@lists.sourceforge.net
Subject: Re: [Kgdb-bugreport] [PATCH] Kill kgdb_serial
References: <20040302213901.GF20227@smtp.west.cox.net> <200403031113.02822.amitkale@emsyssoft.com> <20040303151628.GQ20227@smtp.west.cox.net> <200403041011.39467.amitkale@emsyssoft.com> <20040304152729.GC26065@smtp.west.cox.net> <4047B67A.4050609@mvista.com> <20040304231737.GJ26065@smtp.west.cox.net> <4050DB34.8060704@mvista.com> <20040311223321.GL5169@smtp.west.cox.net>
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Tom Rini wrote:
> On Thu, Mar 11, 2004 at 01:33:40PM -0800, George Anzinger wrote:
> 
> 
>>Tom Rini wrote:
>>
>>
>>>>I am afraid I don't quite understand what he was saying other than early 
>>>>init stuff.  On of the problems with trying early init stuff, by the way, 
>>>>is that a lot of things depend on having alloc up and that happens rather 
>>>>late in the game.
>>>
>>>
>>>I assume you aren't talking about kgdb stuff here (or what would be the
>>>point of going so early) but I believe he was talking about allowing for
>>>stuff that could be done early, to be done early.
>>
>>One of the issues with the UART set up is registering the interrupt handler 
>>with the kernel.  It will fail if alloc is not up.  The -mm patch does two 
>>things with this.  a) It tries every getchar to register the interrupt 
>>handler, and b) it has a module init entry to register it.  This last will 
>>happen late in the bring up and is safe.  a) is there to get it ASAP if you 
>>are actually using kgdb during the bring up.
> 
> 
> There's two ways to look at this.
> - All the more reason to acknowledge that the earliest you can safely
>   get into KGDB is point X, where X is where alloc works, 

Just to get ^C to work?  I would rather give it up entirely!
mappings done
>   if needed, etc, etc, and IFF we change things slightly in kgdboe so
>   that it can call kgdb_schedule_breakpoint() if it needs to as an
>   initial break, and handle setting kgdb_serial to the serial driver in
>   kgdb_arch_init, or something, and remove all of the extra kludges to
>   get us a few lines / function calls earlier on.
> - More and more special cases.

How about a command line set up ASAP which calls a driver entry to do the break. 
  The driver being serial does it NOW, but being some thing that needs 
additional resources, just sets a flag to break when it gets them and returns. 
Seems rather simple.
> 
> Roughly. :)
> 

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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