diff --git a/libc/kernel/uapi/linux/prctl.h b/libc/kernel/uapi/linux/prctl.h
index ccab000..0e86d95 100644
--- a/libc/kernel/uapi/linux/prctl.h
+++ b/libc/kernel/uapi/linux/prctl.h
@@ -192,4 +192,13 @@
 #define PR_GET_AUXV 0x41555856
 #define PR_SET_MEMORY_MERGE 67
 #define PR_GET_MEMORY_MERGE 68
+#define PR_RISCV_V_SET_CONTROL 69
+#define PR_RISCV_V_GET_CONTROL 70
+#define PR_RISCV_V_VSTATE_CTRL_DEFAULT 0
+#define PR_RISCV_V_VSTATE_CTRL_OFF 1
+#define PR_RISCV_V_VSTATE_CTRL_ON 2
+#define PR_RISCV_V_VSTATE_CTRL_INHERIT (1 << 4)
+#define PR_RISCV_V_VSTATE_CTRL_CUR_MASK 0x3
+#define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc
+#define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f
 #endif