The cache information can be extracted from either a Device Tree(DT),
the PPTT ACPI table, or arch registers (clidr_el1 for arm64).
When the DT is used but no cache properties are advertised, the current
code doesn't correctly fallback to using arch information. The changes
fixes the same and also assuse the that L1 data/instruction caches
are private and L2/higher caches are shared when the cache information
is missing in DT/ACPI and is derived form clidr_el1/arch registers.
Currently the cacheinfo is built from the primary CPU prior to secondary
CPUs boot, if the DT/ACPI description contains cache information.
However, if not present, it still reverts to the old behavior, which
allocates the cacheinfo memory on each secondary CPUs which causes
RT kernels to triggers a "BUG: sleeping function called from invalid
context".
The changes here attempts to enable automatic detection for RT kernels
when no DT/ACPI cache information is available, by pre-allocating
cacheinfo memory on the primary CPU.
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Merge tag 'cacheinfo-updates-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into driver-core-next
Sudeep writes:
cacheinfo and arch_topology updates for v6.4
The cache information can be extracted from either a Device Tree(DT),
the PPTT ACPI table, or arch registers (clidr_el1 for arm64).
When the DT is used but no cache properties are advertised, the current
code doesn't correctly fallback to using arch information. The changes
fixes the same and also assuse the that L1 data/instruction caches
are private and L2/higher caches are shared when the cache information
is missing in DT/ACPI and is derived form clidr_el1/arch registers.
Currently the cacheinfo is built from the primary CPU prior to secondary
CPUs boot, if the DT/ACPI description contains cache information.
However, if not present, it still reverts to the old behavior, which
allocates the cacheinfo memory on each secondary CPUs which causes
RT kernels to triggers a "BUG: sleeping function called from invalid
context".
The changes here attempts to enable automatic detection for RT kernels
when no DT/ACPI cache information is available, by pre-allocating
cacheinfo memory on the primary CPU.
* tag 'cacheinfo-updates-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
cacheinfo: Add use_arch[|_cache]_info field/function
arch_topology: Remove early cacheinfo error message if -ENOENT
cacheinfo: Check cache properties are present in DT
cacheinfo: Check sib_leaf in cache_leaves_are_shared()
cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
cacheinfo: Add arm64 early level initializer implementation
cacheinfo: Add arch specific early level initializer
a7b3a470fd