[06/17] riscv: Reset vector register

Message ID	20220921194629.1480202-7-stillson@rivosinc.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org> From: Chris Stillson <stillson@rivosinc.com> To: linux-riscv@lists.infradead.org, jpalmer@dabbelt.com, kvm-riscv@lists.infradead.org Cc: Guo Ren <guoren@linux.alibaba.com>, Vincent Chen <vincent.chen@sifive.com>, Han-Kuan Chen <hankuan.chen@sifive.com>, Greentime Hu <greentime.hu@sifive.com>, Palmer Dabbelt <palmer@rivosinc.com> Subject: [PATCH 06/17] riscv: Reset vector register Date: Wed, 21 Sep 2022 12:46:18 -0700 Message-Id: <20220921194629.1480202-7-stillson@rivosinc.com> In-Reply-To: <20220921194629.1480202-1-stillson@rivosinc.com> References: <20220921194629.1480202-1-stillson@rivosinc.com> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org> Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
Series	Prctl to enable vector commands, previous vector patches rebased \| expand [00/17] Prctl to enable vector commands, previous vector patches rebased [01/17] riscv: Rename __switch_to_aux -> fpu [02/17] riscv: Extending cpufeature.c to detect V-extension [03/17] riscv: Add new csr defines related to vector extension [04/17] riscv: Add vector feature to compile [05/17] riscv: Add has_vector/riscv_vsize to save vector features. [06/17] riscv: Reset vector register [07/17] riscv: Add vector struct and assembler definitions [08/17] riscv: Add task switch support for vector [09/17] riscv: Add ptrace vector support [10/17] riscv: Add sigcontext save/restore for vector [11/17] riscv: signal: Report signal frame size to userspace via auxv [12/17] riscv: Add support for kernel mode vector [13/17] riscv: Add vector extension XOR implementation [14/17] riscv: Fix a kernel panic issue if $s2 is set to a specific value before entering Linux [15/17] riscv: Add V extension to KVM ISA allow list [16/17] riscv: KVM: Add vector lazy save/restore support [17/17] riscv: prctl to enable vector commands

Message ID

20220921194629.1480202-7-stillson@rivosinc.com (mailing list archive)

State

New, archived

Headers

From: Chris Stillson <stillson@rivosinc.com>
To: linux-riscv@lists.infradead.org,
	jpalmer@dabbelt.com,
	kvm-riscv@lists.infradead.org
Cc: Guo Ren <guoren@linux.alibaba.com>,
	Vincent Chen <vincent.chen@sifive.com>,
	Han-Kuan Chen <hankuan.chen@sifive.com>,
	Greentime Hu <greentime.hu@sifive.com>,
	Palmer Dabbelt <palmer@rivosinc.com>
Subject: [PATCH 06/17] riscv: Reset vector register
Date: Wed, 21 Sep 2022 12:46:18 -0700
Message-Id: <20220921194629.1480202-7-stillson@rivosinc.com>
In-Reply-To: <20220921194629.1480202-1-stillson@rivosinc.com>
References: <20220921194629.1480202-1-stillson@rivosinc.com>
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 linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org

Series

Prctl to enable vector commands, previous vector patches rebased | expand

Commit Message

Chris Stillson Sept. 21, 2022, 7:46 p.m. UTC

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

Reset vector registers at boot-time and disable vector instructions
execution for kernel mode.

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>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/riscv/kernel/entry.S |  6 +++---
 arch/riscv/kernel/head.S  | 35 +++++++++++++++++++++++++++++------
 2 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index b9eda3fcbd6d..1e9987376591 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -77,10 +77,10 @@  _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 | SR_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 b865046e4dbb..2c81ca42ec4e 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 | SR_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 | SR_VS
 	csrc CSR_STATUS, t0
 
 #ifdef CONFIG_RISCV_BOOT_SPINWAIT
@@ -431,6 +431,29 @@  ENTRY(reset_regs)
 	csrw	fcsr, 0
 	/* note that the caller must clear SR_FS */
 #endif /* CONFIG_FPU */
+
+#ifdef CONFIG_VECTOR
+	csrr	t0, CSR_MISA
+	li	t1, COMPAT_HWCAP_ISA_V
+	and	t0, t0, t1
+	beqz	t0, .Lreset_regs_done
+
+	/*
+	 * Clear vector registers and reset vcsr
+	 * VLMAX has a defined value, VLEN is a constant,
+	 * and this form of vsetvli is defined to set vl to VLMAX.
+	 */
+	li	t1, SR_VS
+	csrs	CSR_STATUS, t1
+	csrs	CSR_VCSR, x0
+	vsetvli t1, x0, e8, m8, ta, ma
+	vmv.v.i v0, 0
+	vmv.v.i v8, 0
+	vmv.v.i v16, 0
+	vmv.v.i v24, 0
+	/* note that the caller must clear SR_VS */
+#endif /* CONFIG_VECTOR */
+
 .Lreset_regs_done:
 	ret
 END(reset_regs)

[06/17] riscv: Reset vector register

Commit Message

Patch