static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn)
{
if (aarch64_get_insn_class(insn) != AARCH64_INSN_CLS_BR_SYS)
return false;
return aarch64_insn_is_b(insn) ||
aarch64_insn_is_bl(insn) ||
aarch64_insn_is_svc(insn) ||
aarch64_insn_is_hvc(insn) ||
aarch64_insn_is_smc(insn) ||
aarch64_insn_is_brk(insn) ||
aarch64_insn_is_nop(insn);
}
/* Return:
* INSN_REJECTED If instruction is one not allowed to kprobe,
* INSN_GOOD If instruction is supported and uses instruction slot,
* INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
*/
static enum kprobe_insn __kprobes
arm_probe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
/*
* Instructions reading or modifying the PC won't work from the XOL
* slot.
*/
if (aarch64_insn_is_steppable(insn))
return INSN_GOOD;
if (aarch64_insn_is_bcond(insn)) {
asi->handler = simulate_b_cond;
} else if (aarch64_insn_is_cbz(insn) ||
aarch64_insn_is_cbnz(insn)) {
asi->handler = simulate_cbz_cbnz;
} else if (aarch64_insn_is_tbz(insn) ||
aarch64_insn_is_tbnz(insn)) {
asi->handler = simulate_tbz_tbnz;
} else if (aarch64_insn_is_adr_adrp(insn)) {
asi->handler = simulate_adr_adrp;
} else if (aarch64_insn_is_b(insn) ||
aarch64_insn_is_bl(insn)) {
asi->handler = simulate_b_bl;
} else if (aarch64_insn_is_br(insn) ||
aarch64_insn_is_blr(insn) ||
aarch64_insn_is_ret(insn)) {
asi->handler = simulate_br_blr_ret;
} else if (aarch64_insn_is_ldr_lit(insn)) {
asi->handler = simulate_ldr_literal;
} else if (aarch64_insn_is_ldrsw_lit(insn)) {
asi->handler = simulate_ldrsw_literal;
} else {
/*
* Instruction cannot be stepped out-of-line and we don't
* (yet) simulate it.
*/
return INSN_REJECTED;
}
return INSN_GOOD_NO_SLOT;
}