[PATCH 62/62] ARM: tegra: make debug_ll code build for ARMv6

On Wednesday 19 March 2014, Stephen Warren wrote:

On 03/19/2014 01:51 PM, Arnd Bergmann wrote:

quoted

On Wednesday 19 March 2014 13:40:06 Stephen Warren wrote:

quoted

Hmmm. This code is guaranteed to only execute on Tegra (well, perhaps
someone can turn on the wrong debug option and run it on non-Tegra, but
then it's guaranteed not to work since the HW it touches doesn't exist).
As such, the code ought to be able to use ARMv7 instructions.

As a fix for similar issues in assembly code in arch/arm/mach-tegra/*.S,
Makefile there does:

asflags-y                               += -march=armv7-a

(I think you added that? Yes, in 408e713545ca "ARM: tegra: build
assembly files with -march=armv7-a")

Shouldn't we use the same fix in this case too?

That was my first idea, but I couldn't come up with a nice way to do this
for arch/arm/kernel/debug.S, which #includes the specific implementation.

I'd rather not put lots of per-platform hacks into arch/arm/kernel/Makefile.

Oh, I guess the fact it's include makes it a bit more painful.

You could deal with it in Kconfig reasonably easily by having each of
DEBUG_*_UART select a config option indicating how to compile code that
includes DEBUG_LL_INCLUDE, and then have the Makefiles set up asflags
based on those. Still, that would be a lot of work and this patch is
simpler.

Tested-by: Stephen Warren <redacted>
Acked-by: Stephen Warren <redacted>

Ok, thanks for testing! I'm always cautious aobut my own assembly skills,
so I'm glad this worked.

	Arnd