On 2015年01月20日 19:17, Catalin Marinas wrote:
On Wed, Jan 14, 2015 at 03:04:59PM +0000, Hanjun Guo wrote:--- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -64,6 +64,38 @@ static int map_lsapic_id(struct acpi_subtable_header *entry, return 0; }+/* + * On ARM platform, MPIDR value is the hardware ID as apic ID + * on Intel platforms + */ +static int map_gicc_mpidr(struct acpi_subtable_header *entry, + int device_declaration, u32 acpi_id, int *mpidr) +{ + struct acpi_madt_generic_interrupt *gicc = + container_of(entry, struct acpi_madt_generic_interrupt, header); + + if (!(gicc->flags & ACPI_MADT_ENABLED)) + return -ENODEV; + + /* In the GIC interrupt model, logical processors are + * required to have a Processor Device object in the DSDT, + * so we should check device_declaration here + */ + if (device_declaration && (gicc->uid == acpi_id)) { + /* + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2 + * and bits [32:39] Aff3 are meaningful, so pack the Affx + * fields into a single 32 bit identifier to accommodate the + * acpi processor drivers. + */ + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8) + | gicc->arm_mpidr;Nitpick: I would clarify the comment here since "meaningful" doesn't necessarily mean that the other bits are 0. And if they are not, the above masking is not enough. Looking at the ACPI 5.1 spec, bits other than Aff[0-3] must be zero. Same for the pack_mpidr() comment.
OK, how about: /* * bits other than [0:7] Aff0, [8:15] Aff1, [16:23] Aff2 and * [32:39] Aff3 must be 0 which is defined in ACPI 5.1, so pack * the Affx fields into a single 32 bit identifier to accommodate * the acpi processor drivers. */ Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
