Re: [Xen-devel] [PATCH v5 for 4.5] xen/arm: Correctly support WARN_ON

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

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@xxxxxxxxxx>

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.



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