1 files changed, 54 insertions, 0 deletions
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index b9dac57e580a..7df08075fc7a 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -208,3 +208,57 @@ int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
 
 	return aarch64_insn_patch_text_sync(addrs, insns, cnt);
 }
+
+u32 __kprobes aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
+				  u32 insn, u64 imm)
+{
+	u32 immlo, immhi, lomask, himask, mask;
+	int shift;
+
+	switch (type) {
+	case AARCH64_INSN_IMM_ADR:
+		lomask = 0x3;
+		himask = 0x7ffff;
+		immlo = imm & lomask;
+		imm >>= 2;
+		immhi = imm & himask;
+		imm = (immlo << 24) | (immhi);
+		mask = (lomask << 24) | (himask);
+		shift = 5;
+		break;
+	case AARCH64_INSN_IMM_26:
+		mask = BIT(26) - 1;
+		shift = 0;
+		break;
+	case AARCH64_INSN_IMM_19:
+		mask = BIT(19) - 1;
+		shift = 5;
+		break;
+	case AARCH64_INSN_IMM_16:
+		mask = BIT(16) - 1;
+		shift = 5;
+		break;
+	case AARCH64_INSN_IMM_14:
+		mask = BIT(14) - 1;
+		shift = 5;
+		break;
+	case AARCH64_INSN_IMM_12:
+		mask = BIT(12) - 1;
+		shift = 10;
+		break;
+	case AARCH64_INSN_IMM_9:
+		mask = BIT(9) - 1;
+		shift = 12;
+		break;
+	default:
+		pr_err("aarch64_insn_encode_immediate: unknown immediate encoding %d\n",
+			type);
+		return 0;
+	}
+
+	/* Update the immediate field. */
+	insn &= ~(mask << shift);
+	insn |= (imm & mask) << shift;
+
+	return insn;
+}