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> > + u64 base_reg = readq_relaxed(smmu->base + ARM_SMMU_STRTAB_BASE); > > + bool was_2lvl = smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB; > > + phys_addr_t base = base_reg & STRTAB_BASE_ADDR_MASK; > > + u32 fmt = FIELD_GET(STRTAB_BASE_CFG_FMT, cfg_reg); > > + int ret; > > + > > + dev_dbg(smmu->dev, "adopting crashed kernel's stream table\n"); > > + > > + if (fmt == STRTAB_BASE_CFG_FMT_2LVL) { > > + /* > > + * Both kernels run on the same hardware, so it's impossible for > > + * kdump kernel to see the support for linear stream table only. > > + */ > > STRTAB_SPLIT which influences ARM_SMMU_FEAT_2_LVL_STRTAB is a SW choice, so it is > possible to get such mismatch if STRTAB_SPLIT of the newer kernel is larger than the > older kernel. > However, I agree that in that case it's better to refuse the adoption. Yeah this is one of those sneaky ABIs I was talking about for live update. Presumably we will eventually have to make this fully dynamic so the successor can process everything the HW supports. Jason