[PATCH RFC 3/4] powerpc/microwatt: Add early debug UART support for Microwatt

[Segher Boessenkool]

Hi!

On Sat, May 09, 2020 at 03:03:40PM +1000, Paul Mackerras wrote:
> +	__asm__ volatile("mtmsrd %3,0; ldcix %0,%1,%2; mtmsrd %4,0"
> +			 : "=r" (val) : "b" (potato_uart_base), "r" (offset),
> +			   "r" (msr & ~MSR_DR), "r" (msr));

That should be  "=&r"(val)  (an earlyclobber), because when %0 is
written, %4 will still be used later.

Looks fine otherwise.

Reviewed-by: Segher Boessenkool <segher at kernel.crashing.org>


Segher