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| author | Suzuki K Poulose <suzuki.poulose@arm.com> | 2017-01-09 20:28:29 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-01-10 20:11:23 +0300 |
| commit | 8c2dcbd2c4443bad0b4242fb62baa47b260b8f79 (patch) | |
| tree | 0ff1e138c7fdcccdc0ac75e44636f9252bd5df4a /arch/arm64/kernel/insn.c | |
| parent | c9ee0f98662a6e358b5f2969755c938ce9c3a63a (diff) | |
| download | linux-8c2dcbd2c4443bad0b4242fb62baa47b260b8f79.tar.xz | |
arm64: Add helper to decode register from instruction
Add a helper to extract the register field from a given
instruction.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/insn.c')
| -rw-r--r-- | arch/arm64/kernel/insn.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 94b62c1fa4df..1f44cf8c73e6 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -417,6 +417,35 @@ 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) |