From 41a7bb39fede8ecc053c261b86cdfadea45b7b10 Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 19 Nov 2025 12:22:34 +0000 Subject: ACPI / PPTT: Find cache level by cache-id The MPAM table identifies caches by id. The MPAM driver also wants to know the cache level to determine if the platform is of the shape that can be managed via resctrl. Cacheinfo has this information, but only for CPUs that are online. Waiting for all CPUs to come online is a problem for platforms where CPUs are brought online late by user-space. Add a helper that walks every possible cache, until it finds the one identified by cache-id, then return the level. Signed-off-by: James Morse Signed-off-by: Ben Horgan Reviewed-by: Gavin Shan Reviewed-by: Fenghua Yu Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Reviewed-by: Jeremy Linton Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo Signed-off-by: Catalin Marinas --- include/linux/acpi.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include') diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4752ebd48132..be074bdfd4d1 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1542,6 +1542,7 @@ int find_acpi_cpu_topology_cluster(unsigned int cpu); int find_acpi_cpu_topology_package(unsigned int cpu); int find_acpi_cpu_topology_hetero_id(unsigned int cpu); void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus); +int find_acpi_cache_level_from_id(u32 cache_id); #else static inline int acpi_pptt_cpu_is_thread(unsigned int cpu) { @@ -1565,6 +1566,10 @@ static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) } static inline void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus) { } +static inline int find_acpi_cache_level_from_id(u32 cache_id) +{ + return -ENOENT; +} #endif void acpi_arch_init(void); -- cgit v1.2.3