[PATCH v2 1/6] riscv: Make get_insn public for instruction fault handling

[Yicong Yang]

Currently two places (vector and misaligned load/store) need
to get fault instructions for handling and they implement the
function separately. This is a common function so make
get_insn() public in asm/insn.h for doing this job to make it
less fragile and improve the maintainability.

Signed-off-by: Yicong Yang <yang.yicong at picoheart.com>
---
 arch/riscv/include/asm/insn.h        | 53 ++++++++++++++++++++++++++++
 arch/riscv/kernel/traps_misaligned.c | 52 ---------------------------
 arch/riscv/kernel/vector.c           |  6 ++--
 3 files changed, 56 insertions(+), 55 deletions(-)

diff --git a/arch/riscv/include/asm/insn.h b/arch/riscv/include/asm/insn.h
index c3005573e8c9..5f60367c2abc 100644
--- a/arch/riscv/include/asm/insn.h
+++ b/arch/riscv/include/asm/insn.h
@@ -600,4 +600,57 @@ static inline void riscv_insn_insert_utype_itype_imm(u32 *utype_insn, u32 *itype
 	*utype_insn |= (imm & RV_U_IMM_31_12_MASK) + ((imm & BIT(11)) << 1);
 	*itype_insn |= ((imm & RV_I_IMM_11_0_MASK) << RV_I_IMM_11_0_OPOFF);
 }
+
+#define __read_insn(regs, insn, insn_addr, type)			\
+({									\
+	int __ret;							\
+									\
+	if (user_mode(regs)) {						\
+		__ret = get_user(insn, (type __user *) insn_addr);	\
+	} else {							\
+		insn = *(type *)insn_addr;				\
+		__ret = 0;						\
+	}								\
+									\
+	__ret;								\
+})
+
+static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn)
+{
+	ulong insn = 0;
+
+	if (epc & 0x2) {
+		ulong tmp = 0;
+
+		if (__read_insn(regs, insn, epc, u16))
+			return -EFAULT;
+		/* __get_user() uses regular "lw" which sign extend the loaded
+		 * value make sure to clear higher order bits in case we "or" it
+		 * below with the upper 16 bits half.
+		 */
+		insn &= GENMASK(15, 0);
+		if ((insn & __INSN_LENGTH_MASK) != __INSN_LENGTH_32) {
+			*r_insn = insn;
+			return 0;
+		}
+		epc += sizeof(u16);
+		if (__read_insn(regs, tmp, epc, u16))
+			return -EFAULT;
+		*r_insn = (tmp << 16) | insn;
+
+		return 0;
+	} else {
+		if (__read_insn(regs, insn, epc, u32))
+			return -EFAULT;
+		if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) {
+			*r_insn = insn;
+			return 0;
+		}
+		insn &= GENMASK(15, 0);
+		*r_insn = insn;
+
+		return 0;
+	}
+}
+
 #endif /* _ASM_RISCV_INSN_H */
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
index 6e8ae6c66322..f10f14001480 100644
--- a/arch/riscv/kernel/traps_misaligned.c
+++ b/arch/riscv/kernel/traps_misaligned.c
@@ -129,58 +129,6 @@ static unsigned long get_f32_rs(unsigned long insn, u8 fp_reg_offset,
 #define GET_F32_RS2C(insn, regs) (get_f32_rs(insn, 2, regs))
 #define GET_F32_RS2S(insn, regs) (get_f32_rs(RVC_RS2S(insn), 0, regs))
 
-#define __read_insn(regs, insn, insn_addr, type)	\
-({							\
-	int __ret;					\
-							\
-	if (user_mode(regs)) {				\
-		__ret = get_user(insn, (type __user *) insn_addr); \
-	} else {					\
-		insn = *(type *)insn_addr;		\
-		__ret = 0;				\
-	}						\
-							\
-	__ret;						\
-})
-
-static inline int get_insn(struct pt_regs *regs, ulong epc, ulong *r_insn)
-{
-	ulong insn = 0;
-
-	if (epc & 0x2) {
-		ulong tmp = 0;
-
-		if (__read_insn(regs, insn, epc, u16))
-			return -EFAULT;
-		/* __get_user() uses regular "lw" which sign extend the loaded
-		 * value make sure to clear higher order bits in case we "or" it
-		 * below with the upper 16 bits half.
-		 */
-		insn &= GENMASK(15, 0);
-		if ((insn & __INSN_LENGTH_MASK) != __INSN_LENGTH_32) {
-			*r_insn = insn;
-			return 0;
-		}
-		epc += sizeof(u16);
-		if (__read_insn(regs, tmp, epc, u16))
-			return -EFAULT;
-		*r_insn = (tmp << 16) | insn;
-
-		return 0;
-	} else {
-		if (__read_insn(regs, insn, epc, u32))
-			return -EFAULT;
-		if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) {
-			*r_insn = insn;
-			return 0;
-		}
-		insn &= GENMASK(15, 0);
-		*r_insn = insn;
-
-		return 0;
-	}
-}
-
 union reg_data {
 	u8 data_bytes[8];
 	ulong data_ulong;
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index b112166d51e9..1e37810035a9 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -184,8 +184,8 @@ EXPORT_SYMBOL_GPL(riscv_v_vstate_ctrl_user_allowed);
 
 bool riscv_v_first_use_handler(struct pt_regs *regs)
 {
-	u32 __user *epc = (u32 __user *)regs->epc;
-	u32 insn = (u32)regs->badaddr;
+	unsigned long epc = regs->epc;
+	unsigned long insn = regs->badaddr;
 
 	if (!(has_vector() || has_xtheadvector()))
 		return false;
@@ -200,7 +200,7 @@ bool riscv_v_first_use_handler(struct pt_regs *regs)
 
 	/* Get the instruction */
 	if (!insn) {
-		if (__get_user(insn, epc))
+		if (get_insn(regs, epc, &insn))
 			return false;
 	}
 
-- 
2.50.1 (Apple Git-155)