From 428adfc04a2a8d9b25301779bcbc6bde58001430 Mon Sep 17 00:00:00 2001 From: Jeremy Linton Date: Wed, 26 Jun 2019 16:37:16 -0500 Subject: [PATCH] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens to #25688970 commit 56855a99f3d0d1e9f1f4e24f5851f9bf14c83296 upstream ACPI 6.3 adds a flag to indicate that child nodes are all identical cores. This is useful to authoritatively determine if a set of (possibly offline) cores are identical or not. Since the flag doesn't give us a unique id we can generate one and use it to create bitmaps of sibling nodes, or simply in a loop to determine if a subset of cores are identical. Acked-by: Rafael J. Wysocki Tested-by: Hanjun Guo Reviewed-by: Sudeep Holla Signed-off-by: Jeremy Linton Signed-off-by: Will Deacon Signed-off-by: luanshi Acked-by: zou cao Acked-by: Caspar Zhang --- drivers/acpi/pptt.c | 26 ++++++++++++++++++++++++++ include/linux/acpi.h | 5 +++++ 2 files changed, 31 insertions(+) diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c index e149cd9b0fcc..3e51fd742ddc 100644 --- a/drivers/acpi/pptt.c +++ b/drivers/acpi/pptt.c @@ -735,3 +735,29 @@ int find_acpi_cpu_topology_package(unsigned int cpu) return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE, ACPI_PPTT_PHYSICAL_PACKAGE); } + +/** + * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag + * @cpu: Kernel logical CPU number + * + * Determine a unique heterogeneous tag for the given CPU. CPUs with the same + * implementation should have matching tags. + * + * The returned tag can be used to group peers with identical implementation. + * + * The search terminates when a level is found with the identical implementation + * flag set or we reach a root node. + * + * Due to limitations in the PPTT data structure, there may be rare situations + * where two cores in a heterogeneous machine may be identical, but won't have + * the same tag. + * + * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found. + * Otherwise returns a value which represents a group of identical cores + * similar to this CPU. + */ +int find_acpi_cpu_topology_hetero_id(unsigned int cpu) +{ + return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE, + ACPI_PPTT_ACPI_IDENTICAL); +} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 7ab204eb92cc..8399af68167c 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1303,6 +1303,7 @@ static inline int lpit_read_residency_count_address(u64 *address) int acpi_pptt_cpu_is_thread(unsigned int cpu); int find_acpi_cpu_topology(unsigned int cpu, int level); int find_acpi_cpu_topology_package(unsigned int cpu); +int find_acpi_cpu_topology_hetero_id(unsigned int cpu); int find_acpi_cpu_cache_topology(unsigned int cpu, int level); #else static inline int acpi_pptt_cpu_is_thread(unsigned int cpu) @@ -1317,6 +1318,10 @@ static inline int find_acpi_cpu_topology_package(unsigned int cpu) { return -EINVAL; } +static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) +{ + return -EINVAL; +} static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level) { return -EINVAL; -- GitLab