I'm tweaking RISC-V 32-bit kernel and toolchains, and seems by default some syscalls are not enabled -- for example, adjtimex. In kernel headers (usr/include/asm-generic/unistd.h)it is guarded by the macro: #if defined(__ARCH_WANT_TIME32_SYSCALLS) || __BITS_PER_LONG != 32 ... #define __NR_adjtimex 171 __SC_3264(__NR_adjtimex, sys_adjtimex_time32, sys_adjtimex) which is not enabled on 32-bit because __ARCH_WANT_TIME32_SYSCALLS is not defined for RISC-V, and there's no 32-bit counterparts in the unistd.h file ,unlike, for example, ppoll: #if __BITS_PER_LONG == 32 ... #define __NR_ppoll_time64 414 __SC_COMP(__NR_ppoll_time64, sys_ppoll, compat_sys_ppoll_time64) In other architectures like ARM 32-bit, I find adjtimex listed in the syscalls.tbl file, which doesn't exist for RISC-V. So is syscalls like adjtimex just shouldn't exist for RISC-V 32-bit? If not, is it good to manually define __ARCH_WANT_TIME32_SYSCALLS? I got uclibc compiled and run after defining this macro in kernel, but I'm not sure if this is good.