riscv: Add prctl controls for userspace vector management

This patch add two riscv-specific prctls, to allow usespace control the
use of vector unit:

 * PR_RISCV_V_SET_CONTROL: control the permission to use Vector at next,
   or all following execve for a thread. Turning off a thread's Vector
   live is not possible since libraries may have registered ifunc that
   may execute Vector instructions.
 * PR_RISCV_V_GET_CONTROL: get the same permission setting for the
   current thread, and the setting for following execve(s).

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
Reviewed-by: Vincent Chen <vincent.chen@sifive.com>
Link: https://lore.kernel.org/r/20230605110724.21391-22-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index f23d9a16507f..3c36aeade991 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -294,4 +294,15 @@ struct prctl_mm_map {
 
 #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 /* _LINUX_PRCTL_H */