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author | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2024-06-06 12:42:38 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2024-06-06 17:30:15 +0300 |
commit | ababa16fd9bd0e2727a1c31c4fb68d6be053bddc (patch) | |
tree | dd002a2b30d778bdde7e30bd7f9583e34211ed07 /drivers/acpi/processor_core.c | |
parent | d011c022efe275791897668aa421e2db9f2e6450 (diff) | |
download | linux-ababa16fd9bd0e2727a1c31c4fb68d6be053bddc.tar.xz |
irqchip/gic-v3: Enable non-coherent redistributors/ITSes ACPI probing
The GIC architecture specification defines a set of registers for
redistributors and ITSes that control the sharebility and cacheability
attributes of redistributors/ITSes initiator ports on the interconnect
(GICR_[V]PROPBASER, GICR_[V]PENDBASER, GITS_BASER<n>).
Architecturally the GIC provides a means to drive shareability and
cacheability attributes signals but it is not mandatory for designs to
wire up the corresponding interconnect signals that control the
cacheability/shareability of transactions.
Redistributors and ITSes interconnect ports can be connected to
non-coherent interconnects that are not able to manage the
shareability/cacheability attributes; this implicitly makes the
redistributors and ITSes non-coherent observers.
To enable non-coherent GIC designs on ACPI based systems, parse the MADT
GICC/GICR/ITS subtables non-coherent flags to determine whether the
respective components are non-coherent observers and force the
shareability attributes to be programmed into the redistributors and
ITSes registers.
An ACPI global function (acpi_get_madt_revision()) is added to retrieve
the MADT revision, in that it is essential to check the MADT revision
before checking for flags that were added with MADT revision 7 so that
if the kernel is booted with an ACPI MADT table with revision < 7 it
skips parsing the newly added flags (that should be zeroed reserved
values for MADT versions < 7 but they could turn out to be buggy and
should be ignored).
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240606094238.757649-2-lpieralisi@kernel.org
Diffstat (limited to 'drivers/acpi/processor_core.c')
-rw-r--r-- | drivers/acpi/processor_core.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index b203cfe28550..915713c0e9b7 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -215,6 +215,21 @@ phys_cpuid_t __init acpi_map_madt_entry(u32 acpi_id) return rv; } +int __init acpi_get_madt_revision(void) +{ + struct acpi_table_header *madt = NULL; + int revision; + + if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_MADT, 0, &madt))) + return -EINVAL; + + revision = madt->revision; + + acpi_put_table(madt); + + return revision; +} + static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id) { struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; |