x86/apic/of: Fix CPU devicetree-node lookups
authorJohan Hovold <johan@kernel.org>
Fri, 12 Mar 2021 09:20:33 +0000 (10:20 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 25 Mar 2021 08:04:18 +0000 (09:04 +0100)
commit21536d7b7e6f58a2a7b3af3909c5150fe1fceb8c
tree0a5f9fd42fce50c6f914b3188dcc32aa367d6347
parent95247d24c4d4973146a9e7175ec0803f734cf50e
x86/apic/of: Fix CPU devicetree-node lookups

commit dd926880da8dbbe409e709c1d3c1620729a94732 upstream.

Architectures that describe the CPU topology in devicetree and do not have
an identity mapping between physical and logical CPU ids must override the
default implementation of arch_match_cpu_phys_id().

Failing to do so breaks CPU devicetree-node lookups using of_get_cpu_node()
and of_cpu_device_node_get() which several drivers rely on. It also causes
the CPU struct devices exported through sysfs to point to the wrong
devicetree nodes.

On x86, CPUs are described in devicetree using their APIC ids and those
do not generally coincide with the logical ids, even if CPU0 typically
uses APIC id 0.

Add the missing implementation of arch_match_cpu_phys_id() so that CPU-node
lookups work also with SMP.

Apart from fixing the broken sysfs devicetree-node links this likely does
not affect current users of mainline kernels on x86.

Fixes: 4e07db9c8db8 ("x86/devicetree: Use CPU description from Device Tree")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210312092033.26317-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/apic/apic.c