From: Andi Kleen <andi@firstfloor.org>
To: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Arjan van de Ven <arjan@linux.intel.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] x86: don't destroy %rbp on kernel-mode faults
Date: Mon, 19 May 2008 23:16:56 +0200 [thread overview]
Message-ID: <4831EE48.5050908@firstfloor.org> (raw)
In-Reply-To: <20080519200230.GA12210@damson.getinternet.no>
Vegard Nossum wrote:
> Hi,
>
> The RFC part of this patch is: Does anybody see why touching %rcx would
> be bad? It certainly looks like %ecx is free. This fixes the stacktrace
> problem I was seeing, and Pekka tested a bootup to userspace. (Pekka also
> did half of the debugging. When will git allow multiple authors for a
> patch? :-))
The patch is ok, but I'm sure there's lots of other assembler code that
destroys %rbp when it was saved elsewhere.
When I wrote all the assembler the assumption was always that a real
unwinder would be used for backtraces, not frame pointer.
-Andi
next prev parent reply other threads:[~2008-05-19 21:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-19 20:02 [RFC][PATCH] x86: don't destroy %rbp on kernel-mode faults Vegard Nossum
2008-05-19 20:22 ` Arjan van de Ven
2008-05-19 21:16 ` Andi Kleen [this message]
2008-05-22 12:07 ` Vegard Nossum
2008-05-22 13:07 ` Andi Kleen
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