[PATCH] ARM: kdgb: use .inst for data to be assembled as intruction

[Dave Martin]

On Thu, Jul 25, 2013 at 03:49:38PM +0100, Ben Dooks wrote:
> The arch_kgdb_breakpoint() function uses an inline assembly directive
> to assemble a specific instruction using .word. This means the linker
> will not treat is as an instruction, and therefore incorrectly swap
> the endian-ness if running BE8.
> 
> Note, not tested, please comment if this is wrong.
> 
> Signed-off-by: Ben Dooks <ben.dooks at codethink.co.uk>
> ---
>  arch/arm/include/asm/kgdb.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
> index 48066ce..76227c8 100644
> --- a/arch/arm/include/asm/kgdb.h
> +++ b/arch/arm/include/asm/kgdb.h
> @@ -41,7 +41,7 @@
>  
>  static inline void arch_kgdb_breakpoint(void)
>  {
> -	asm(".word 0xe7ffdeff");
> +	asm(".inst 0xe7ffdeff");

Yikes, this isn't going to work in a Thumb kernel.

We should make HAVE_ARCH_KGDB depend on !THUMB2_KERNEL until/unless that
gets fixed...  It looks like the incompatibilities may be more extensive
than just this one instruction.


For the ARM case, similarly to the other patches, please use the __inst
macros from <asm/opcodes.h> instead of emitting the opcode explicitly.

Cheers
---Dave