On Wed, 2015-01-07 at 16:12 +1100, Anton Blanchard wrote:

Thanks for looking into this. Does that mean we were just getting lucky
with the previous version:

static inline struct thread_info *current_thread_info(void)
{
        register unsigned long sp asm("r1");

        return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
}
 
ie a static register asm instead of a global one. If so the safest fix
for now might be to just eat the overead of a register move:

static inline struct thread_info *current_thread_info(void)
{
        unsigned long sp;

        asm("mr %0,1": "=r"(sp));
        return (struct thread_info *)(sp & ~(THREAD_SIZE-1));

You could avoid the register move by doing a rlwinm/rldicr in inline
asm, if it matters enough.

-Scott