Unverified Commit 74abe5a3 authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt
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riscv: Disable Vector Instructions for kernel itself 



Disable vector instructions execution for kernel mode at its entrances.
This helps find illegal uses of vector in the kernel space, which is
similar to the fpu.

Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Co-developed-by: default avatarVincent Chen <vincent.chen@sifive.com>
Signed-off-by: default avatarVincent Chen <vincent.chen@sifive.com>
Co-developed-by: default avatarHan-Kuan Chen <hankuan.chen@sifive.com>
Signed-off-by: default avatarHan-Kuan Chen <hankuan.chen@sifive.com>
Co-developed-by: default avatarGreentime Hu <greentime.hu@sifive.com>
Signed-off-by: default avatarGreentime Hu <greentime.hu@sifive.com>
Signed-off-by: default avatarVineet Gupta <vineetg@rivosinc.com>
Signed-off-by: default avatarAndy Chiu <andy.chiu@sifive.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarHeiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: default avatarHeiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230605110724.21391-7-andy.chiu@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 6b533828

arch/riscv/kernel/entry.S

+3 −3
Original line number Diff line number Diff line
@@ -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

arch/riscv/kernel/head.S

+6 −6
Original line number Diff line number Diff line
@@ -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