diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index f6573c335f4c..6e0a44bad305 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -398,6 +398,11 @@ static void free_cache_attributes(unsigned int cpu) cache_shared_cpu_map_remove(cpu); } +int __weak early_cache_level(unsigned int cpu) +{ + return -ENOENT; +} + int __weak init_cache_level(unsigned int cpu) { return -ENOENT; @@ -423,32 +428,71 @@ int allocate_cache_info(int cpu) int fetch_cache_info(unsigned int cpu) { - struct cpu_cacheinfo *this_cpu_ci; + struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); unsigned int levels = 0, split_levels = 0; int ret; if (acpi_disabled) { ret = init_of_cache_level(cpu); - if (ret < 0) - return ret; } else { ret = acpi_get_cache_info(cpu, &levels, &split_levels); - if (ret < 0) + if (!ret) { + this_cpu_ci->num_levels = levels; + /* + * This assumes that: + * - there cannot be any split caches (data/instruction) + * above a unified cache + * - data/instruction caches come by pair + */ + this_cpu_ci->num_leaves = levels + split_levels; + } + } + + if (ret || !cache_leaves(cpu)) { + ret = early_cache_level(cpu); + if (ret) return ret; - this_cpu_ci = get_cpu_cacheinfo(cpu); - this_cpu_ci->num_levels = levels; - /* - * This assumes that: - * - there cannot be any split caches (data/instruction) - * above a unified cache - * - data/instruction caches come by pair - */ - this_cpu_ci->num_leaves = levels + split_levels; + if (!cache_leaves(cpu)) + return -ENOENT; + + this_cpu_ci->early_ci_levels = true; } - if (!cache_leaves(cpu)) + + return allocate_cache_info(cpu); +} + +static inline int init_level_allocate_ci(unsigned int cpu) +{ + unsigned int early_leaves = cache_leaves(cpu); + + /* Since early initialization/allocation of the cacheinfo is allowed + * via fetch_cache_info() and this also gets called as CPU hotplug + * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped + * as it will happen only once (the cacheinfo memory is never freed). + * Just populate the cacheinfo. However, if the cacheinfo has been + * allocated early through the arch-specific early_cache_level() call, + * there is a chance the info is wrong (this can happen on arm64). In + * that case, call init_cache_level() anyway to give the arch-specific + * code a chance to make things right. + */ + if (per_cpu_cacheinfo(cpu) && !ci_cacheinfo(cpu)->early_ci_levels) + return 0; + + if (init_cache_level(cpu) || !cache_leaves(cpu)) return -ENOENT; + /* + * Now that we have properly initialized the cache level info, make + * sure we don't try to do that again the next time we are called + * (e.g. as CPU hotplug callbacks). + */ + ci_cacheinfo(cpu)->early_ci_levels = false; + + if (cache_leaves(cpu) <= early_leaves) + return 0; + + kfree(per_cpu_cacheinfo(cpu)); return allocate_cache_info(cpu); } @@ -456,23 +500,10 @@ int detect_cache_attributes(unsigned int cpu) { int ret; - /* Since early initialization/allocation of the cacheinfo is allowed - * via fetch_cache_info() and this also gets called as CPU hotplug - * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped - * as it will happen only once (the cacheinfo memory is never freed). - * Just populate the cacheinfo. - */ - if (per_cpu_cacheinfo(cpu)) - goto populate_leaves; - - if (init_cache_level(cpu) || !cache_leaves(cpu)) - return -ENOENT; - - ret = allocate_cache_info(cpu); + ret = init_level_allocate_ci(cpu); if (ret) return ret; -populate_leaves: /* * populate_cache_leaves() may completely setup the cache leaves and * shared_cpu_map or it may leave it partially setup. diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h index 908e19d17f49..6147b2672555 100644 --- a/include/linux/cacheinfo.h +++ b/include/linux/cacheinfo.h @@ -76,9 +76,11 @@ struct cpu_cacheinfo { unsigned int num_levels; unsigned int num_leaves; bool cpu_map_populated; + bool early_ci_levels; }; struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu); +int early_cache_level(unsigned int cpu); int init_cache_level(unsigned int cpu); int init_of_cache_level(unsigned int cpu); int populate_cache_leaves(unsigned int cpu);