From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v5 for 4.5] xen/arm: Correctly support
	WARN_ON
Date: Thu, 2 Oct 2014 12:56:49 -0400
Message-ID: <20141002165649.GG1715@laptop.dumpdata.com>
References: <1412096285-4400-1-git-send-email-julien.grall@linaro.org>
	<1412165900.4861.32.camel@citrix.com>
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To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: xen-devel@lists.xenproject.org, Julien Grall <julien.grall@linaro.org>, tim@xen.org, stefano.stabellini@citrix.com
List-Id: xen-devel@lists.xenproject.org

On Wed, Oct 01, 2014 at 01:18:20PM +0100, Ian Campbell wrote:
> On Tue, 2014-09-30 at 17:58 +0100, Julien Grall wrote:
> > Currently the hypervisor will hang if it hits a WARN_ON.
> > 
> > The implementation uses an undefined instruction, made ourself because ARM
> > don't provide one, to implement BUG/ASSERT/WARN_ON, and sets up the
> > different tables (one for each type) which contain useful information.
> > 
> > This is based on the x86 implementation (include/asm-x86/bug.h). Unfortunately
> > the structure can't be shared because many ARM{32,64} gcc versions doesn't
> > correctly support %c. The support for executing a function in an exception handler
> > is also keep unimplemented on ARM. Therefore, dump_execution_state is
> > implemented as WARN()
> > 
> > The current opcode used to go in exception mode may not be undefined on ARM64.
> > Use the instruction "brk" to generate a software debug exception.
> > 
> > Signed-off-by: Julien Grall <julien.grall@linaro.org>
> 
> Acked...
> 
> > ---
> >     This is a bug fix for Xen 4.5. It make WARN_ON working correctly
> >     when it has been hit in the hypervisor.
> 
> ...and applied on that basis.

Excellent!
> 
>