KERNEL_STACK_SHIFT   73 arch/xtensa/include/asm/kmem_layout.h #define KERNEL_STACK_SIZE	(1 << KERNEL_STACK_SHIFT)
KERNEL_STACK_SHIFT   17 arch/xtensa/include/asm/thread_info.h #define CURRENT_SHIFT KERNEL_STACK_SHIFT
KERNEL_STACK_SHIFT  125 arch/xtensa/include/asm/thread_info.h #define THREAD_SIZE_ORDER (KERNEL_STACK_SHIFT - PAGE_SHIFT)