diff options
Diffstat (limited to 'kernel/arch/arm64/kernel/insn.c')
-rw-r--r-- | kernel/arch/arm64/kernel/insn.c | 65 |
1 files changed, 62 insertions, 3 deletions
diff --git a/kernel/arch/arm64/kernel/insn.c b/kernel/arch/arm64/kernel/insn.c index 30eb88e5b..c08b9ad6f 100644 --- a/kernel/arch/arm64/kernel/insn.c +++ b/kernel/arch/arm64/kernel/insn.c @@ -77,6 +77,14 @@ bool __kprobes aarch64_insn_is_nop(u32 insn) } } +bool aarch64_insn_is_branch_imm(u32 insn) +{ + return (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn) || + aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn) || + aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)); +} + static DEFINE_RAW_SPINLOCK(patch_lock); static void __kprobes *patch_map(void *addr, int fixmap) @@ -93,9 +101,8 @@ static void __kprobes *patch_map(void *addr, int fixmap) return addr; BUG_ON(!page); - set_fixmap(fixmap, page_to_phys(page)); - - return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); + return (void *)set_fixmap_offset(fixmap, page_to_phys(page) + + (uintaddr & ~PAGE_MASK)); } static void __kprobes patch_unmap(int fixmap) @@ -1057,6 +1064,58 @@ u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst, return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift); } +/* + * Decode the imm field of a branch, and return the byte offset as a + * signed value (so it can be used when computing a new branch + * target). + */ +s32 aarch64_get_branch_offset(u32 insn) +{ + s32 imm; + + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_26, insn); + return (imm << 6) >> 4; + } + + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_19, insn); + return (imm << 13) >> 11; + } + + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) { + imm = aarch64_insn_decode_immediate(AARCH64_INSN_IMM_14, insn); + return (imm << 18) >> 16; + } + + /* Unhandled instruction */ + BUG(); +} + +/* + * Encode the displacement of a branch in the imm field and return the + * updated instruction. + */ +u32 aarch64_set_branch_offset(u32 insn, s32 offset) +{ + if (aarch64_insn_is_b(insn) || aarch64_insn_is_bl(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn, + offset >> 2); + + if (aarch64_insn_is_cbz(insn) || aarch64_insn_is_cbnz(insn) || + aarch64_insn_is_bcond(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn, + offset >> 2); + + if (aarch64_insn_is_tbz(insn) || aarch64_insn_is_tbnz(insn)) + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_14, insn, + offset >> 2); + + /* Unhandled instruction */ + BUG(); +} + bool aarch32_insn_is_wide(u32 insn) { return insn >= 0xe800; |