On Wed, Sep 09, 2015 at 03:09:46PM -0600, Al Stone wrote: > Currently, the BAD_MADT_ENTRY macro is used to do a very simple sanity > check on the various subtables that are defined for the MADT. The check > compares the size of the subtable data structure as defined by ACPICA to > the length entry in the subtable. If they are not the same, the assumption > is that the subtable is incorrect. > > Over time, the ACPI spec has allowed for MADT subtables where this can > never be true (the local SAPIC subtable, for example). Or, more recently, > the spec has accumulated some minor flaws where there are three possible > sizes for a subtable, all of which are valid, but only for specific versions > of the spec (the GICC subtable). In both cases, BAD_MADT_ENTRY reports these > subtables as bad when they are not. In order to retain some sanity check > on the MADT subtables, we now have to special case these subtables. Of > necessity, these special cases have ended up in arch-dependent code (arm64) > or an arch has simply decided to forgo the check (ia64). > > This patch set replaces the BAD_MADT_ENTRY macro with a function called > bad_madt_entry(). This function uses a data set of details about the > subtables to provide more sanity checking than before: > > -- is the subtable legal for the version given in the FADT? > > -- is the subtable legal for the revision of the MADT in use? > > -- is the subtable of the proper length (including checking > on the one variable length subtable that is currently ignored), > given the FADT version and the MADT revision? > > Further, this patch set adds in the call to bad_madt_entry() from the > acpi_table_parse_madt() function, allowing it to be used consistently > by all architectures, for all subtables, and removing the need for each > of the subtable traversal callback functions to use BAD_MADT_ENTRY. > > In theory, as the ACPI specification changes, we would only have to add > additional information to the data set describing the MADT subtables in > order to continue providing sanity checks, even when new subtables are > added. > > These patches have been tested on an APM Mustang (arm64) and are known to > work there. They have also been cross-compiled for x86 and ia64 with no > known failures. > > Changes for v3: > -- Reviewed-and-tested-by from Sudeep Holla for arm64 parts > -- Clearer language in error messages (Graeme Gregory, Timur Tabi) > -- Double checked that inserting call to bad_madt_entry() into the > function acpi_parse_entries() does not impact current behavior > (Sudeep Holla) > > Changes for v2: > -- Acked-by on 2/5 from Marc Zyngier and Catalin Marinas for ARM > -- Correct faulty end of loop test found by Timur Tabi > > > Al Stone (5): > ACPI: add in a bad_madt_entry() function to eventually replace the > macro > ACPI / ARM64: remove usage of BAD_MADT_ENTRY/BAD_MADT_GICC_ENTRY > ACPI / IA64: remove usage of BAD_MADT_ENTRY > ACPI / X86: remove usage of BAD_MADT_ENTRY > ACPI: remove definition of BAD_MADT_ENTRY macro > > arch/arm64/include/asm/acpi.h | 8 -- > arch/arm64/kernel/smp.c | 2 - > arch/ia64/kernel/acpi.c | 20 ---- > arch/x86/kernel/acpi/boot.c | 27 ----- > drivers/acpi/tables.c | 245 +++++++++++++++++++++++++++++++++++++++++- > drivers/irqchip/irq-gic.c | 6 -- > include/linux/acpi.h | 4 - > 7 files changed, 244 insertions(+), 68 deletions(-) > Whole series looks good to me apart from minor whitespace nit. Reviewed-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx> Thanks G -- 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
