diff options
| -rw-r--r-- | arch/arm64/kernel/insn.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 2929ada..816d03c 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -35,6 +35,7 @@ #define AARCH64_INSN_SF_BIT BIT(31) #define AARCH64_INSN_N_BIT BIT(22) +#define AARCH64_INSN_LSL_12 BIT(22) static int aarch64_insn_encoding_class[] = { AARCH64_INSN_CLS_UNKNOWN, @@ -903,9 +904,18 @@ u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst, return AARCH64_BREAK_FAULT; } + /* We can't encode more than a 24bit value (12bit + 12bit shift) */ + if (imm & ~(BIT(24) - 1)) + goto out; + + /* If we have something in the top 12 bits... */ if (imm & ~(SZ_4K - 1)) { - pr_err("%s: invalid immediate encoding %d\n", __func__, imm); - return AARCH64_BREAK_FAULT; + /* ... and in the low 12 bits -> error */ + if (imm & (SZ_4K - 1)) + goto out; + + imm >>= 12; + insn |= AARCH64_INSN_LSL_12; } insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, dst); @@ -913,6 +923,10 @@ u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst, insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, src); return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm); + +out: + pr_err("%s: invalid immediate encoding %d\n", __func__, imm); + return AARCH64_BREAK_FAULT; } u32 aarch64_insn_gen_bitfield(enum aarch64_insn_register dst, |
