Merge patch series "riscv: misaligned: Add ZCB handling and fix sleeping function"

Nylon Chen <[email protected]> says:

1. Adds support for ZCB compressed instructions (C.LHU, C.LH, C.SH).

2. Fixes a bug where copy_from/to_user() calls in non-sleepable contexts
triggered attempts to sleep.

Signed-off-by: Zong Li <[email protected]>
Signed-off-by: Nylon Chen [email protected]

Nylon Chen (2):
  riscv: misaligned: Add handling for ZCB instructions
  riscv: misaligned: fix sleeping function called during misaligned
    access handling

* b4-shazam-merge:
  riscv: misaligned: fix sleeping function called during misaligned access handling
  riscv: misaligned: Add handling for ZCB instructions

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

Author: palmer-dabbelt

arch/riscv/kernel/traps_misaligned.c

@@ -88,6 +88,13 @@
 #define INSN_MATCH_C_FSWSP		0xe002
 #define INSN_MASK_C_FSWSP		0xe003
 
+#define INSN_MATCH_C_LHU		0x8400
+#define INSN_MASK_C_LHU			0xfc43
+#define INSN_MATCH_C_LH			0x8440
+#define INSN_MASK_C_LH			0xfc43
+#define INSN_MATCH_C_SH			0x8c00
+#define INSN_MASK_C_SH			0xfc43
+
 #define INSN_LEN(insn)			((((insn) & 0x3) < 0x3) ? 2 : 4)
 
 #if defined(CONFIG_64BIT)
@@ -431,6 +438,13 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs)
 		fp = 1;
 		len = 4;
 #endif
+	} else if ((insn & INSN_MASK_C_LHU) == INSN_MATCH_C_LHU) {
+		len = 2;
+		insn = RVC_RS2S(insn) << SH_RD;
+	} else if ((insn & INSN_MASK_C_LH) == INSN_MATCH_C_LH) {
+		len = 2;
+		shift = 8 * (sizeof(ulong) - len);
+		insn = RVC_RS2S(insn) << SH_RD;
 	} else {
 		regs->epc = epc;
 		return -1;
@@ -441,7 +455,7 @@ static int handle_scalar_misaligned_load(struct pt_regs *regs)
 
 	val.data_u64 = 0;
 	if (user_mode(regs)) {
-		if (copy_from_user(&val, (u8 __user *)addr, len))
+		if (copy_from_user_nofault(&val, (u8 __user *)addr, len))
 			return -1;
 	} else {
 		memcpy(&val, (u8 *)addr, len);
@@ -530,6 +544,9 @@ static int handle_scalar_misaligned_store(struct pt_regs *regs)
 		len = 4;
 		val.data_ulong = GET_F32_RS2C(insn, regs);
 #endif
+	} else if ((insn & INSN_MASK_C_SH) == INSN_MATCH_C_SH) {
+		len = 2;
+		val.data_ulong = GET_RS2S(insn, regs);
 	} else {
 		regs->epc = epc;
 		return -1;
@@ -539,7 +556,7 @@ static int handle_scalar_misaligned_store(struct pt_regs *regs)
 		return -EOPNOTSUPP;
 
 	if (user_mode(regs)) {
-		if (copy_to_user((u8 __user *)addr, &val, len))
+		if (copy_to_user_nofault((u8 __user *)addr, &val, len))
 			return -1;
 	} else {
 		memcpy((u8 *)addr, &val, len);