1.global call_trusted 2.arch_extension sec 3 4call_trusted: 5 stmfd sp!, {r4-r12,lr} 6 mov r6, #0xff 7 mov r12, #0 8 dsb 9 isb 10 dmb 11 smc 1 12 ldmfd sp!, {r4-r12,lr} 13 bx lr 14 15