Add a helper to extract the register field from a given
instruction.
Signed-off-by: Suzuki K. Poulose <suzuki.poul...@arm.com>
---
arch/arm64/include/asm/insn.h | 2 ++
arch/arm64/kernel/insn.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 30e50eb..6dea3bc 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -289,6 +289,8 @@ enum aarch64_insn_encoding_class aarch64_get_insn_class(u32
insn);
u64 aarch64_insn_decode_immediate(enum aarch64_insn_imm_type type, u32 insn);
u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type,
u32 insn, u64 imm);
+u32 aarch64_insn_decode_register(enum aarch64_insn_register_type type,
+ u32 insn);
u32 aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr,
enum aarch64_insn_branch_type type);
u32 aarch64_insn_gen_comp_branch_imm(unsigned long pc, unsigned long addr,
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index f341866..4286fed 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -388,6 +388,35 @@ u32 __kprobes aarch64_insn_encode_immediate(enum
aarch64_insn_imm_type type,
return insn;
}
+u32 aarch64_insn_decode_register(enum aarch64_insn_register_type type,
+ u32 insn)
+{
+ int shift;
+
+ switch (type) {
+ case AARCH64_INSN_REGTYPE_RT:
+ case AARCH64_INSN_REGTYPE_RD:
+ shift = 0;
+ break;
+ case AARCH64_INSN_REGTYPE_RN:
+ shift = 5;
+ break;
+ case AARCH64_INSN_REGTYPE_RT2:
+ case AARCH64_INSN_REGTYPE_RA:
+ shift = 10;
+ break;
+ case AARCH64_INSN_REGTYPE_RM:
+ shift = 16;
+ break;
+ default:
+ pr_err("%s: unknown register type encoding %d\n", __func__,
+ type);
+ return 0;
+ }
+
+ return (insn >> shift) & GENMASK(4, 0);
+}
+
static u32 aarch64_insn_encode_register(enum aarch64_insn_register_type type,
u32 insn,
enum aarch64_insn_register reg)
--
1.7.9.5
--
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