[PATCH -next v18 05/20] riscv: Disable Vector Instructions for kernel itself

Andy Chiu
2023-04-14T15:59:28Z

From: Guo Ren <guoren@linux.alibaba.com>

Disable vector instructions execution for kernel mode at its entrances.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Co-developed-by: Han-Kuan Chen <hankuan.chen@sifive.com>
Signed-off-by: Han-Kuan Chen <hankuan.chen@sifive.com>
Co-developed-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
arch/riscv/kernel/entry.S | 6 +++---
arch/riscv/kernel/head.S | 12 ++++++------
2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 3fbb100bc9e4..e9ae284a55c1 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -48,10 +48,10 @@ _save_context:
* Disable user-mode memory access as it should only be set in the
* actual user copy routines.
*
- * Disable the FPU to detect illegal usage of floating point in kernel
- * space.
+ * Disable the FPU/Vector to detect illegal usage of floating point
+ * or vector in kernel space.
*/
- li t0, SR_SUM | SR_FS
+ li t0, SR_SUM | SR_FS_VS

REG_L s0, TASK_TI_USER_SP(tp)
csrrc s1, CSR_STATUS, t0
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 3fd6a4bd9c3e..e16bb2185d55 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -140,10 +140,10 @@ secondary_start_sbi:
.option pop

/*
- * Disable FPU to detect illegal usage of
- * floating point in kernel space
+ * Disable FPU & VECTOR to detect illegal usage of
+ * floating point or vector in kernel space
*/
- li t0, SR_FS
+ li t0, SR_FS_VS
csrc CSR_STATUS, t0

/* Set trap vector to spin forever to help debug */
@@ -234,10 +234,10 @@ pmp_done:
.option pop

/*
- * Disable FPU to detect illegal usage of
- * floating point in kernel space
+ * Disable FPU & VECTOR to detect illegal usage of
+ * floating point or vector in kernel space
*/
- li t0, SR_FS
+ li t0, SR_FS_VS
csrc CSR_STATUS, t0

#ifdef CONFIG_RISCV_BOOT_SPINWAIT
--
2.17.1