On Mon, Apr 11, 2016 at 5:13 AM, Lv Zheng <lv.zheng@xxxxxxxxx> wrote: > > This patch converts the initrd table override mechanism to the table > upgrade mechanism by restricting its usage to the tables released with > compatibility and more recent revision. > > This use case has been encouraged by the ACPI specification: > 1. OEMID: > An OEM-supplied string that identifies the OEM. > 2. OEM Table ID: > An OEM-supplied string that the OEM uses to identify the particular data > table. This field is particularly useful when defining a definition > block to distinguish definition block functions. OEM assigns each > dissimilar table a new OEM Table Id. > 3. OEM Revision: > An OEM-supplied revision number. Larger numbers are assumed to be newer > revisions. > For OEMs, good practices will ensure consistency when assigning OEMID and > OEM Table ID fields in any table. The intent of these fields is to allow > for a binary control system that support services can use. Because many > support function can be automated, it is useful when a tool can > programatically determine which table release is a compatible and more > recent revision of a prior table on the same OEMID and OEM Table ID. > > The facility can now be used by the vendors to upgrade wrong tables for bug > fixing purpose, thus lockdep disabling taint is not suitable for it and it > should be a default 'y' option to implement the spec encouraged use case. > I agree that we should not force lockdep disabling. I wonder if we should add a new taint (like the one I proposed in the overlay patch set) to see in bug reports that the ACPI tables have been modified. Also, do we need a new config option? IMO it would be better if we can keep the existing config option and do the following: * if CONFIG_ACPI_INITRD_TABLE_OVERRIDE is set: allow arbitrary overrides (preserve the current behavior) * if CONFIG_ACPI_INITRD_TABLE_OVERRIDE is not set: allow upgrades based on the revision number * allow adding new tables regardless of CONFIG_ACPI_INITRD_TABLE_OVERRIDE -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
