3 files changed, 54 insertions, 22 deletions

diff --git a/arch/riscv/lib/riscv_v_helpers.c b/arch/riscv/lib/riscv_v_helpers.c
index be38a93cedae..7bbdfc6d4552 100644
--- a/arch/riscv/lib/riscv_v_helpers.c
+++ b/arch/riscv/lib/riscv_v_helpers.c
@@ -16,8 +16,11 @@
 #ifdef CONFIG_MMU
 size_t riscv_v_usercopy_threshold = CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD;
 int __asm_vector_usercopy(void *dst, void *src, size_t n);
+int __asm_vector_usercopy_sum_enabled(void *dst, void *src, size_t n);
 int fallback_scalar_usercopy(void *dst, void *src, size_t n);
-asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n)
+int fallback_scalar_usercopy_sum_enabled(void *dst, void *src, size_t n);
+asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n,
+				     bool enable_sum)
 {
 	size_t remain, copied;
 
@@ -26,7 +29,8 @@ asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n)
 		goto fallback;
 
 	kernel_vector_begin();
-	remain = __asm_vector_usercopy(dst, src, n);
+	remain = enable_sum ? __asm_vector_usercopy(dst, src, n) :
+			      __asm_vector_usercopy_sum_enabled(dst, src, n);
 	kernel_vector_end();
 
 	if (remain) {
@@ -40,6 +44,7 @@ asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n)
 	return remain;
 
 fallback:
-	return fallback_scalar_usercopy(dst, src, n);
+	return enable_sum ? fallback_scalar_usercopy(dst, src, n) :
+			    fallback_scalar_usercopy_sum_enabled(dst, src, n);
 }
 #endif
diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
index 6a9f116bb545..4efea1b3326c 100644
--- a/arch/riscv/lib/uaccess.S
+++ b/arch/riscv/lib/uaccess.S
@@ -17,14 +17,43 @@ SYM_FUNC_START(__asm_copy_to_user)
 	ALTERNATIVE("j fallback_scalar_usercopy", "nop", 0, RISCV_ISA_EXT_ZVE32X, CONFIG_RISCV_ISA_V)
 	REG_L	t0, riscv_v_usercopy_threshold
 	bltu	a2, t0, fallback_scalar_usercopy
-	tail enter_vector_usercopy
+	li	a3, 1
+	tail 	enter_vector_usercopy
 #endif
-SYM_FUNC_START(fallback_scalar_usercopy)
+SYM_FUNC_END(__asm_copy_to_user)
+EXPORT_SYMBOL(__asm_copy_to_user)
+SYM_FUNC_ALIAS(__asm_copy_from_user, __asm_copy_to_user)
+EXPORT_SYMBOL(__asm_copy_from_user)
 
+SYM_FUNC_START(fallback_scalar_usercopy)
 	/* Enable access to user memory */
-	li t6, SR_SUM
-	csrs CSR_STATUS, t6
+	li	t6, SR_SUM
+	csrs 	CSR_STATUS, t6
+	mv 	t6, ra
 
+	call 	fallback_scalar_usercopy_sum_enabled
+
+	/* Disable access to user memory */
+	mv 	ra, t6
+	li 	t6, SR_SUM
+	csrc 	CSR_STATUS, t6
+	ret
+SYM_FUNC_END(fallback_scalar_usercopy)
+
+SYM_FUNC_START(__asm_copy_to_user_sum_enabled)
+#ifdef CONFIG_RISCV_ISA_V
+	ALTERNATIVE("j fallback_scalar_usercopy_sum_enabled", "nop", 0, RISCV_ISA_EXT_ZVE32X, CONFIG_RISCV_ISA_V)
+	REG_L	t0, riscv_v_usercopy_threshold
+	bltu	a2, t0, fallback_scalar_usercopy_sum_enabled
+	li	a3, 0
+	tail 	enter_vector_usercopy
+#endif
+SYM_FUNC_END(__asm_copy_to_user_sum_enabled)
+SYM_FUNC_ALIAS(__asm_copy_from_user_sum_enabled, __asm_copy_to_user_sum_enabled)
+EXPORT_SYMBOL(__asm_copy_from_user_sum_enabled)
+EXPORT_SYMBOL(__asm_copy_to_user_sum_enabled)
+
+SYM_FUNC_START(fallback_scalar_usercopy_sum_enabled)
 	/*
 	 * Save the terminal address which will be used to compute the number
 	 * of bytes copied in case of a fixup exception.
@@ -178,23 +207,12 @@ SYM_FUNC_START(fallback_scalar_usercopy)
 	bltu	a0, t0, 4b	/* t0 - end of dst */
 
 .Lout_copy_user:
-	/* Disable access to user memory */
-	csrc CSR_STATUS, t6
 	li	a0, 0
 	ret
-
-	/* Exception fixup code */
 10:
-	/* Disable access to user memory */
-	csrc CSR_STATUS, t6
 	sub a0, t5, a0
 	ret
-SYM_FUNC_END(__asm_copy_to_user)
-SYM_FUNC_END(fallback_scalar_usercopy)
-EXPORT_SYMBOL(__asm_copy_to_user)
-SYM_FUNC_ALIAS(__asm_copy_from_user, __asm_copy_to_user)
-EXPORT_SYMBOL(__asm_copy_from_user)
-
+SYM_FUNC_END(fallback_scalar_usercopy_sum_enabled)
 
 SYM_FUNC_START(__clear_user)
 
diff --git a/arch/riscv/lib/uaccess_vector.S b/arch/riscv/lib/uaccess_vector.S
index 7c45f26de4f7..03b5560609a2 100644
--- a/arch/riscv/lib/uaccess_vector.S
+++ b/arch/riscv/lib/uaccess_vector.S
@@ -24,7 +24,18 @@ SYM_FUNC_START(__asm_vector_usercopy)
 	/* Enable access to user memory */
 	li	t6, SR_SUM
 	csrs	CSR_STATUS, t6
+	mv	t6, ra
 
+	call 	__asm_vector_usercopy_sum_enabled
+
+	/* Disable access to user memory */
+	mv 	ra, t6
+	li 	t6, SR_SUM
+	csrc	CSR_STATUS, t6
+	ret
+SYM_FUNC_END(__asm_vector_usercopy)
+
+SYM_FUNC_START(__asm_vector_usercopy_sum_enabled)
 loop:
 	vsetvli iVL, iNum, e8, ELEM_LMUL_SETTING, ta, ma
 	fixup vle8.v vData, (pSrc), 10f
@@ -36,8 +47,6 @@ loop:
 
 	/* Exception fixup for vector load is shared with normal exit */
 10:
-	/* Disable access to user memory */
-	csrc	CSR_STATUS, t6
 	mv	a0, iNum
 	ret
 
@@ -49,4 +58,4 @@ loop:
 	csrr	t2, CSR_VSTART
 	sub	iNum, iNum, t2
 	j	10b
-SYM_FUNC_END(__asm_vector_usercopy)
+SYM_FUNC_END(__asm_vector_usercopy_sum_enabled)