arch_align_stack
extern unsigned long arch_align_stack(unsigned long sp);
extern unsigned long arch_align_stack(unsigned long sp);
extern unsigned long arch_align_stack(unsigned long sp);
extern unsigned long arch_align_stack(unsigned long sp);
extern unsigned long arch_align_stack(unsigned long sp);
extern unsigned long arch_align_stack(unsigned long sp);
#ifndef arch_align_stack
extern unsigned long arch_align_stack(unsigned long sp);
p = arch_align_stack(p);
sp = arch_align_stack(bprm->p);
stack_top = arch_align_stack(stack_top);