32-bit Thumb-2 breakpoints

[Catalin Marinas]

On Mon, 2010-01-11 at 21:58 +0000, Daniel Jacobowitz wrote:
> The kernel currently reserves two architecturally undefined
> instructions for breakpoints, one ARM and one Thumb.  I suggest
> another for Thumb-2, provisionally 0xfff7 0xffcf, but I'm open
> to any other suggestion.  Any comments?  If that sounds OK,
> I can put together a patch.

I find the reasons good enough to add a 32-bit Thumb-2 breakpoint
instruction.

Regarding the opcode, can we not use a permanently undefined one? There
is A6.3.4 in the ARM ARM defining such encoding. Maybe something like
0xf7f0 a000 (or 0xa000 f7f0 if you write it as a 32-bit word).

-- 
Catalin