Index: sys/riscv/riscv/machdep.c
===================================================================
--- sys/riscv/riscv/machdep.c
+++ sys/riscv/riscv/machdep.c
@@ -368,11 +368,16 @@
 	tf = td->td_frame;
 
 	/*
-	 * Make sure the processor mode has not been tampered with and
-	 * interrupts have not been disabled.
-	 * Supervisor interrupts in user mode are always enabled.
+	 * Permit changes to the USTATUS bits of SSTATUS.
+	 *
+	 * Ignore writes to read-only bits (SD, XS).
+	 *
+	 * Ignore writes to the FS field as set_fpcontext() will set
+	 * it explicitly.
 	 */
-	if ((mcp->mc_gpregs.gp_sstatus & SSTATUS_SPP) != 0)
+	if (((mcp->mc_gpregs.gp_sstatus ^ tf->tf_sstatus) &
+	    ~(SSTATUS_SD | SSTATUS_XS_MASK | SSTATUS_FS_MASK | SSTATUS_UPIE |
+	    SSTATUS_UIE)) != 0)
 		return (EINVAL);
 
 	memcpy(tf->tf_t, mcp->mc_gpregs.gp_t, sizeof(tf->tf_t));
@@ -426,7 +431,12 @@
 {
 #ifdef FPE
 	struct pcb *curpcb;
+#endif
 
+	td->td_frame->tf_sstatus &= ~SSTATUS_FS_MASK;
+	td->td_frame->tf_sstatus |= SSTATUS_FS_OFF;
+
+#ifdef FPE
 	critical_enter();
 
 	if ((mcp->mc_flags & _MC_FP_VALID) != 0) {
@@ -436,6 +446,7 @@
 		    sizeof(mcp->mc_fpregs));
 		curpcb->pcb_fcsr = mcp->mc_fpregs.fp_fcsr;
 		curpcb->pcb_fpflags = mcp->mc_fpregs.fp_flags & PCB_FP_USERMASK;
+		td->td_frame->tf_sstatus |= SSTATUS_FS_CLEAN;
 	}
 
 	critical_exit();