From: Jeremy Linton jeremy.linton@arm.com
Commit bbd1b70639f785a970d998f35155c713f975e3ac upstream.
ACPI 6.3 adds a flag to the CPU node to indicate whether the given PE is a thread. Add a function to return that information for a given linux logical CPU.
Signed-off-by: Jeremy Linton jeremy.linton@arm.com Reviewed-by: Sudeep Holla sudeep.holla@arm.com Reviewed-by: Robert Richter rrichter@marvell.com Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Will Deacon will@kernel.org [jpg: backport for 4.19, replace acpi_pptt_warn_missing()] Signed-off-by: John Garry john.garry@huawei.com --- drivers/acpi/pptt.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 5 +++++ 2 files changed, 57 insertions(+)
diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c index da031b1df6f5..9dbf86a0c827 100644 --- a/drivers/acpi/pptt.c +++ b/drivers/acpi/pptt.c @@ -509,6 +509,44 @@ static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag) return retval; }
+/** + * check_acpi_cpu_flag() - Determine if CPU node has a flag set + * @cpu: Kernel logical CPU number + * @rev: The minimum PPTT revision defining the flag + * @flag: The flag itself + * + * Check the node representing a CPU for a given flag. + * + * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or + * the table revision isn't new enough. + * 1, any passed flag set + * 0, flag unset + */ +static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag) +{ + struct acpi_table_header *table; + acpi_status status; + u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu); + struct acpi_pptt_processor *cpu_node = NULL; + int ret = -ENOENT; + + status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); + if (ACPI_FAILURE(status)) { + pr_warn_once("No PPTT table found, cpu topology may be inaccurate\n"); + return ret; + } + + if (table->revision >= rev) + cpu_node = acpi_find_processor_node(table, acpi_cpu_id); + + if (cpu_node) + ret = (cpu_node->flags & flag) != 0; + + acpi_put_table(table); + + return ret; +} + /** * acpi_find_last_cache_level() - Determines the number of cache levels for a PE * @cpu: Kernel logical cpu number @@ -573,6 +611,20 @@ int cache_setup_acpi(unsigned int cpu) return status; }
+/** + * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread + * @cpu: Kernel logical CPU number + * + * Return: 1, a thread + * 0, not a thread + * -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or + * the table revision isn't new enough. + */ +int acpi_pptt_cpu_is_thread(unsigned int cpu) +{ + return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD); +} + /** * find_acpi_cpu_topology() - Determine a unique topology value for a given cpu * @cpu: Kernel logical cpu number diff --git a/include/linux/acpi.h b/include/linux/acpi.h index b4d23b3a2ef2..59a416dfcaaa 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1291,10 +1291,15 @@ static inline int lpit_read_residency_count_address(u64 *address) #endif
#ifdef CONFIG_ACPI_PPTT +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_cache_topology(unsigned int cpu, int level); #else +static inline int acpi_pptt_cpu_is_thread(unsigned int cpu) +{ + return -EINVAL; +} static inline int find_acpi_cpu_topology(unsigned int cpu, int level) { return -EINVAL;