diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 05a16b1f0aee..51ebfd23e007 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -319,6 +319,7 @@ void do_trap_ecall_u(struct pt_regs *regs)
 
 		regs->epc += 4;
 		regs->orig_a0 = regs->a0;
+		regs->a0 = -ENOSYS;
 
 		riscv_v_vstate_discard(regs);
 
@@ -328,8 +329,7 @@ void do_trap_ecall_u(struct pt_regs *regs)
 
 		if (syscall >= 0 && syscall < NR_syscalls)
 			syscall_handler(regs, syscall);
-		else if (syscall != -1)
-			regs->a0 = -ENOSYS;
+
 		/*
 		 * Ultimately, this value will get limited by KSTACK_OFFSET_MAX(),
 		 * so the maximum stack offset is 1k bytes (10 bits).