PSL_MD
#define PSL_USERSTATIC (PSL_BL|PSL_RB|PSL_MD|PSL_IMASK|PSL_FD|PSL_MBO|PSL_MBZ)
#define KERNELMODE(sr) ((sr) & PSL_MD)
if ((tf->tf_ssr & PSL_MD) == 0)
sf->sf_sr = PSL_MD | /* kernel mode, interrupt enable */