Hi Alexey, On Mon, Jul 9, 2018 at 2:48 PM Alexey Brodkin <Alexey.Brodkin@xxxxxxxxxxxx> wrote: > Atomic instructions require data they operate on to be aligned > according to data size. I.e. 32-bit atomic values must be 32-bit > aligned while 64-bit values must be 64-bit aligned. > > Otherwise even if CPU may handle not-aligend normal data access, > still atomic instructions fail and typically raise an exception > leaving us dead in the water. > > This came-up during lengthly discussion here: > http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004022.html > > Signed-off-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx> Thanks for your patch! > --- a/include/asm-generic/atomic64.h > +++ b/include/asm-generic/atomic64.h > @@ -13,7 +13,7 @@ > #define _ASM_GENERIC_ATOMIC64_H > > typedef struct { > - long long counter; > + u64 __aligned(8) counter; I think you can drop the change to this file, as this is the generic implementation using spinlocks, for processors that don't have 64-bit atomic instructions. > } atomic64_t; Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
