1 // SPDX-License-Identifier: GPL-2.0-only
3  * CPU/APIC topology
24 #define pr_fmt(fmt) "CPU topo: " fmt
25 #include <linux/cpu.h>
35 #include "cpu.h"
38  * Map cpu index to physical APIC ID
48 /* Used for CPU number allocation and parallel CPU bringup */
49 u32 cpuid_to_apicid[] __ro_after_init = { [0 ... NR_CPUS - 1] = BAD_APICID, };
52 static struct { DECLARE_BITMAP(map, MAX_LOCAL_APIC); } apic_maps[TOPO_MAX_DOMAIN] __ro_after_init;
56  * with 1 as CPU #0 is reserved for the boot CPU.
70 #define domain_weight(_dom)	bitmap_weight(apic_maps[_dom].map, MAX_LOCAL_APIC)
72 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)  in arch_match_cpu_phys_id()  argument
74 	return phys_id == (u64)cpuid_to_apicid[cpu];  in arch_match_cpu_phys_id()
78 static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid)  in cpu_mark_primary_thread()  argument
80 	if (!(apicid & (__max_threads_per_core - 1)))  in cpu_mark_primary_thread()
81 		cpumask_set_cpu(cpu, &__cpu_primary_thread_mask);  in cpu_mark_primary_thread()
84 static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { }  in cpu_mark_primary_thread()  argument
95 	return apicid & (UINT_MAX << x86_topo_system.dom_shifts[dom - 1]);  in topo_apicid()
102 	/* CPU# to APICID mapping is persistent once it is established */  in topo_lookup_cpuid()
107 	return -ENODEV;  in topo_lookup_cpuid()
112 	int cpu = topo_lookup_cpuid(apic_id);  in topo_get_cpunr()  local
114 	if (cpu >= 0)  in topo_get_cpunr()
115 		return cpu;  in topo_get_cpunr()
120 static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id)  in topo_set_cpuids()  argument
123 	early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;  in topo_set_cpuids()
124 	early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;  in topo_set_cpuids()
126 	set_cpu_present(cpu, true);  in topo_set_cpuids()
139 	 * CPU is the real BSP. If it is not, then do not register the APIC  in check_for_real_bsp()
144 	 * because the boot CPU APIC ID is registered before that without  in check_for_real_bsp()
152 	 * BSP bit in the APICBASE MSR. If the CPU does not have the  in check_for_real_bsp()
163 		 * If the boot CPU has the APIC BSP bit set then the  in check_for_real_bsp()
164 		 * firmware enumeration is agreeing. If the CPU does not  in check_for_real_bsp()
180 		pr_warn("Assuming crash kernel. Limiting to one CPU to prevent machine INIT\n");  in check_for_real_bsp()
185 	pr_warn("Boot CPU APIC ID not the first enumerated APIC ID: %x != %x\n",  in check_for_real_bsp()
190 		 * The boot CPU has the APIC BSP bit set. Use it and complain  in check_for_real_bsp()
208 				    unsigned long *map)  in topo_unit_count()  argument
216 	for (id = find_next_bit(map, end, lvlid); id < end; id = find_next_bit(map, end, ++id))  in topo_unit_count()
223 	int cpu, dom;  in topo_register_apic()  local
229 		 * Double registration is valid in case of the boot CPU  in topo_register_apic()
235 			cpu = 0;  in topo_register_apic()
237 			cpu = topo_get_cpunr(apic_id);  in topo_register_apic()
239 		cpuid_to_apicid[cpu] = apic_id;  in topo_register_apic()
240 		topo_set_cpuids(cpu, apic_id, acpi_id);  in topo_register_apic()
250 			pr_info_once("Ignoring hot-pluggable APIC ID %x in present package.\n",  in topo_register_apic()
265 		set_bit(topo_apicid(apic_id, dom), apic_maps[dom].map);  in topo_register_apic()
269  * topology_register_apic - Register an APIC in early topology maps
272  * @present:	True if the corresponding CPU is present
277 		pr_err_once("APIC ID %x exceeds kernel limit of: %x\n", apic_id, MAX_LOCAL_APIC - 1);  in topology_register_apic()
287 	/* CPU numbers exhausted? */  in topology_register_apic()
289 		pr_warn_once("CPU limit of %d reached. Ignoring further CPUs\n", nr_cpu_ids);  in topology_register_apic()
298  * topology_register_boot_apic - Register the boot CPU APIC
301  * Separate so CPU #0 can be assigned
312  * topology_get_logical_id - Retrieve the logical ID at a given topology domain level
321  *  - >= 0:	The requested logical ID
322  *  - -ERANGE:	@apicid is out of range
323  *  - -ENODEV:	@apicid is not registered
331 		return -ERANGE;  in topology_get_logical_id()
332 	if (!test_bit(lvlid, apic_maps[at_level].map))  in topology_get_logical_id()
333 		return -ENODEV;  in topology_get_logical_id()
335 	return bitmap_weight(apic_maps[at_level].map, lvlid);  in topology_get_logical_id()
340  * topology_unit_count - Retrieve the count of specified units at a given topology domain level
365 	if (!test_bit(lvlid, apic_maps[at_level].map))  in topology_unit_count()
371 	return topo_unit_count(lvlid, at_level, apic_maps[which_units].map);  in topology_unit_count()
376  * topology_hotplug_apic - Handle a physical hotplugged APIC after boot
382 	int cpu;  in topology_hotplug_apic()  local
385 		return -EINVAL;  in topology_hotplug_apic()
388 	if (!test_bit(apic_id, apic_maps[TOPO_SMT_DOMAIN].map))  in topology_hotplug_apic()
389 		return -ENODEV;  in topology_hotplug_apic()
391 	cpu = topo_lookup_cpuid(apic_id);  in topology_hotplug_apic()
392 	if (cpu < 0)  in topology_hotplug_apic()
393 		return -ENOSPC;  in topology_hotplug_apic()
396 	topo_set_cpuids(cpu, apic_id, acpi_id);  in topology_hotplug_apic()
397 	cpu_mark_primary_thread(cpu, apic_id);  in topology_hotplug_apic()
398 	return cpu;  in topology_hotplug_apic()
402  * topology_hotunplug_apic - Remove a physical hotplugged APIC after boot
403  * @cpu:	The CPU number for which the APIC ID is removed
405 void topology_hotunplug_apic(unsigned int cpu)  in topology_hotunplug_apic()  argument
407 	u32 apic_id = cpuid_to_apicid[cpu];  in topology_hotunplug_apic()
412 	per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;  in topology_hotunplug_apic()
414 	set_cpu_present(cpu, false);  in topology_hotunplug_apic()
422  * topology_apply_cmdline_limits_early - Apply topology command line limits early
464 	unsigned int cnta, cntb, cpu, allowed = 1;  in topology_init_possible_cpus()  local
481 			disabled += assigned - nr_cpu_ids;  in topology_init_possible_cpus()
491 	disabled = allowed - assigned;  in topology_init_possible_cpus()
502 	__max_dies_per_package = 1U << (get_count_order(cntb) - get_count_order(cnta));  in topology_init_possible_cpus()
517 	firstid = find_first_bit(apic_maps[TOPO_SMT_DOMAIN].map, MAX_LOCAL_APIC);  in topology_init_possible_cpus()
530 	/* Assign CPU numbers to non-present CPUs */  in topology_init_possible_cpus()
531 	for (apicid = 0; disabled; disabled--, apicid++) {  in topology_init_possible_cpus()
532 		apicid = find_next_andnot_bit(apic_maps[TOPO_SMT_DOMAIN].map, phys_cpu_present_map,  in topology_init_possible_cpus()
539 	for (cpu = 0; cpu < allowed; cpu++) {  in topology_init_possible_cpus()
540 		apicid = cpuid_to_apicid[cpu];  in topology_init_possible_cpus()
542 		set_cpu_possible(cpu, true);  in topology_init_possible_cpus()
547 		cpu_mark_primary_thread(cpu, apicid);  in topology_init_possible_cpus()
548 		set_cpu_present(cpu, test_bit(apicid, phys_cpu_present_map));  in topology_init_possible_cpus()
553  * Late SMP disable after sizing CPU masks when APIC/IOAPIC setup failed.