__msr_s
asm volatile(__msr_s(SYS_SVCR_SMSTART_SM_EL0, "xzr"));
asm volatile(__msr_s(SYS_SVCR_SMSTOP_SM_EL0, "xzr"));
asm volatile(__msr_s(SYS_SVCR_SMSTOP_SMZA_EL0, "xzr"));
"1: " __msr_s(at_op, "%3") "\n" \
asm volatile(ALTERNATIVE(__msr_s(r##nvh, "%x0"), \
__msr_s(r##vh, "%x0"), \
asm volatile(__msr_s(r, "xzr")); \
asm volatile(__msr_s(r, "%x0") : : "r" (__val)); \
asm volatile(__msr_s(r, "%x0") : : "rZ" (__val)); \