powerpc: Don't use local named register variable in current_thread_info

LLVM doesn't support local named register variables and is unlikely
to. current_thread_info is using one, fix it by moving it out and
calling it __current_r1().

I gave it a bit of an obscure name because we don't want anyone else
using it - they should use current_stack_pointer(). This specific
case is performance critical and we can't afford to call a function
to get it. Furthermore it isn't important to know exactly where in
the stack we are since we mask the lower bits.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anton Blanchard 2014-10-31 14:47:25 +11:00 committed by Michael Ellerman
parent e88f157de5
commit a3e5b356b3

View File

@ -71,13 +71,12 @@ struct thread_info {
#define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
/* how to get the thread information struct from C */
register unsigned long __current_r1 asm("r1");
static inline struct thread_info *current_thread_info(void)
{
register unsigned long sp asm("r1");
/* gcc4, at least, is smart enough to turn this into a single
* rlwinm for ppc32 and clrrdi for ppc64 */
return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
return (struct thread_info *)(__current_r1 & ~(THREAD_SIZE-1));
}
#endif /* __ASSEMBLY__ */