From: Fabrice Bellard <fabrice@bellard.org>
To: qemu-devel@nongnu.org
Cc: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 0/5] Debugger enhancements
Date: Sat, 31 May 2008 20:33:02 +0200 [thread overview]
Message-ID: <484199DE.3080904@bellard.org> (raw)
In-Reply-To: <200805311805.03739.paul@codesourcery.com>
Paul Brook wrote:
>> 2) The current watchpoint code is not implemented correctly so it is not
>> safe to improve it using the same system (IMHO it should not have been
>> commited in its current state). A correct implementation should not
>> delay the DEBUG exception. It should be implemented like the "normal"
>> MMU exceptions.
>
> On most targets watchpoint traps occur after the instruction completes, so you
> have to defer the DEBUG exception.
> Normal MMU faults occur before the instruction completes.
If this is the wanted behavior then the same system as the Self
Modifying Code on x86 should be used. Basically it consists in doing as
a MMU fault and single stepping one instruction after. Unfortunately I
fear the implementation will be complicated.
Fabrice.
next prev parent reply other threads:[~2008-05-31 18:34 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-31 12:55 [Qemu-devel] [PATCH 0/5] Debugger enhancements Jan Kiszka
2008-05-31 13:15 ` [Qemu-devel] [PATCH 3/5] Add read watchpoint support Jan Kiszka
2008-05-31 13:15 ` [Qemu-devel] [PATCH 2/5] Watchpoint length and type awareness Jan Kiszka
2008-05-31 13:26 ` [Qemu-devel] [PATCH 4/5] Report exact PC on watchpoint hit Jan Kiszka
2008-05-31 14:11 ` Paul Brook
2008-05-31 14:42 ` Jan Kiszka
2008-05-31 15:17 ` Paul Brook
2008-05-31 13:44 ` [Qemu-devel] [PATCH 5/5] Enhance SMP guest debugging Jan Kiszka
2008-05-31 13:49 ` [Qemu-devel] [PATCH 1/5] Refactor breakpoint API and gdbstub integration Jan Kiszka
2008-05-31 16:50 ` [Qemu-devel] [PATCH 0/5] Debugger enhancements Fabrice Bellard
2008-05-31 17:05 ` Paul Brook
2008-05-31 17:29 ` [Qemu-devel] " Jan Kiszka
2008-05-31 18:33 ` Fabrice Bellard [this message]
2008-06-01 13:54 ` Jan Kiszka
2008-06-01 12:38 ` [Qemu-devel] " Jamie Lokier
2008-06-01 13:56 ` [Qemu-devel] " Jan Kiszka
2008-05-31 17:20 ` Jan Kiszka
2008-05-31 18:42 ` Fabrice Bellard
2008-06-01 0:06 ` Paul Brook
2008-06-01 13:53 ` Jan Kiszka
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