ababa16fd9
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 |
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kunit | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rv | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| ufs | ||
| vdso | ||
| video | ||
| xen | ||