On Thu, Jun 11, 2015 at 08:45:10PM +0100, [email protected] wrote: > From: Al Stone <[email protected]> > > The BAD_MADT_ENTRY() macro is designed to work for all of the subtables > of the MADT. In the ACPI 5.1 version of the spec, the struct for the > GICC subtable (struct acpi_madt_generic_interrupt) is 76 bytes long; in > ACPI 6.0, the struct is 80 bytes long. But, there is only one definition > in ACPICA for this struct -- and that is the 6.0 version. Hence, when > BAD_MADT_ENTRY() compares the struct size to the length in the GICC > subtable, it fails if 5.1 structs are in use, and there are systems in > the wild that have them. > > This patch adds the BAD_MADT_GICC_ENTRY() that checks the GICC subtable > only, accounting for the difference in specification versions that are > possible. The BAD_MADT_ENTRY() will continue to work as is for all other > MADT subtables.
Unfortunately that's nothing new, it seems. ia64 put in place a quite nifty solution to that (I *guess* owing to ACPI 3.0 updates to Local sapic specs), have a look at: arch/ia64/kernel/acpi.c acpi_parse_lsacpi() /*Skip BAD_MADT_ENTRY check, as lsapic size could vary */ We remove the check, job done ;-) > Signed-off-by: Al Stone <[email protected]> > Reviewed-by: Hanjun Guo <[email protected]> > Reviewed-by: Graeme Gregory <[email protected]> > > CC: Rafael J. Wysocki <[email protected]> > CC: Len Brown <[email protected]> > > --- > include/linux/acpi.h | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index 33ed313..8a83f91 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -127,6 +127,13 @@ static inline void acpi_initrd_override(void *data, > size_t size) > (!entry) || (unsigned long)entry + sizeof(*entry) > end || \ > ((struct acpi_subtable_header *)entry)->length < sizeof(*entry)) > > +#define BAD_MADT_GICC_ENTRY(entry, end) ( \ > + (!entry) || (unsigned long)entry + sizeof(*entry) > end || \ > + ((ACPI_FADT_SPEC_VERSION == ACPI_SPEC_VERSION(5,1)) && \ > + (entry->header.length != 76)) || \ > + ((ACPI_FADT_SPEC_VERSION == ACPI_SPEC_VERSION(6,0)) && \ > + (entry->header.length != 80))) I would make those length magic numbers ACPICA defines at least. It is not a GICC only issue, that's true for all MADT subtables that change size with versions so, maybe we can replace the sizeof(*entry) in BAD_MADT_ENTRY with a macro compound statement returning the subtable length (where you can add a switch case on entry->type and return sizeof(*entry) in the default case) ? Overkill ? Certainly ugly, but at least you do not need to patch anything else. I am inclined to relegate these checks to ACPICA tools (statically) altogether. It is better to check Len and Rafael opinion on this first before coding it. Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
