On Mon, Oct 19, 2020 at 12:12:46PM +0000, Christophe Leroy wrote:
> GCC 4.9 sometimes fails to build with "m<>" constraint in
> inline assembly.
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -223,7 +223,7 @@ do {
> \
> "1: " op "%U1%X1 %0,%1 # put_user\n" \
> EX_TABLE(1b, %l2) \
> : \
> - : "r" (x), "m<>" (*addr) \
> + : "r" (x), "m"UPD_CONSTR (*addr) \
> : \
> : label)
>
> @@ -294,7 +294,7 @@ extern long __get_user_bad(void);
> ".previous\n" \
> EX_TABLE(1b, 3b) \
> : "=r" (err), "=r" (x) \
> - : "m<>" (*addr), "i" (-EFAULT), "0" (err))
> + : "m"UPD_CONSTR (*addr), "i" (-EFAULT), "0" (err))
Wow, ugly! But these are the only two places that use this, so
Acked-by: Segher Boessenkool <seg...@kernel.crashing.org>
I just hope that we get rid of 4.9 before we would use this a lot more ;-)
Segher
