[v8, 08/10] riscv: vector: use a mask to write vstate_ctrl

[Andy Chiu]

riscv_v_ctrl_set() should only touch bits within
PR_RISCV_V_VSTATE_CTRL_MASK. So, use the mask when we really set task's
vstate_ctrl.

Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
---
Changelog v6:
 - splitted out from v3
---
 arch/riscv/kernel/vector.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index 66e8c6ab09d2..c1f28bc89ec6 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -122,7 +122,8 @@ static inline void riscv_v_ctrl_set(struct task_struct *tsk, int cur, int nxt,
 	ctrl |= VSTATE_CTRL_MAKE_NEXT(nxt);
 	if (inherit)
 		ctrl |= PR_RISCV_V_VSTATE_CTRL_INHERIT;
-	tsk->thread.vstate_ctrl = ctrl;
+	tsk->thread.vstate_ctrl &= ~PR_RISCV_V_VSTATE_CTRL_MASK;
+	tsk->thread.vstate_ctrl |= ctrl;
 }
 
 bool riscv_v_vstate_ctrl_user_allowed(void)
-- 
2.17.1