diff options
Diffstat (limited to 'arch/x86/kernel/cpu/topology.c')
-rw-r--r-- | arch/x86/kernel/cpu/topology.c | 585 |
1 files changed, 471 insertions, 114 deletions
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index dc13670356..d17c9b71eb 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -1,167 +1,524 @@ -// SPDX-License-Identifier: GPL-2.0 +// SPDX-License-Identifier: GPL-2.0-only /* - * Check for extended topology enumeration cpuid leaf 0xb and if it - * exists, use it for populating initial_apicid and cpu topology - * detection. + * CPU/APIC topology + * + * The APIC IDs describe the system topology in multiple domain levels. + * The CPUID topology parser provides the information which part of the + * APIC ID is associated to the individual levels: + * + * [PACKAGE][DIEGRP][DIE][TILE][MODULE][CORE][THREAD] + * + * The root space contains the package (socket) IDs. + * + * Not enumerated levels consume 0 bits space, but conceptually they are + * always represented. If e.g. only CORE and THREAD levels are enumerated + * then the DIE, MODULE and TILE have the same physical ID as the PACKAGE. + * + * If SMT is not supported, then the THREAD domain is still used. It then + * has the same physical ID as the CORE domain and is the only child of + * the core domain. + * + * This allows a unified view on the system independent of the enumerated + * domain levels without requiring any conditionals in the code. */ - +#define pr_fmt(fmt) "CPU topo: " fmt #include <linux/cpu.h> + +#include <xen/xen.h> + #include <asm/apic.h> -#include <asm/memtype.h> -#include <asm/processor.h> +#include <asm/hypervisor.h> +#include <asm/io_apic.h> +#include <asm/mpspec.h> +#include <asm/smp.h> #include "cpu.h" -/* leaf 0xb SMT level */ -#define SMT_LEVEL 0 +/* + * Map cpu index to physical APIC ID + */ +DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_apicid, BAD_APICID); +DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, CPU_ACPIID_INVALID); +EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid); +EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid); -/* extended topology sub-leaf types */ -#define INVALID_TYPE 0 -#define SMT_TYPE 1 -#define CORE_TYPE 2 -#define DIE_TYPE 5 +/* Bitmap of physically present CPUs. */ +DECLARE_BITMAP(phys_cpu_present_map, MAX_LOCAL_APIC) __read_mostly; -#define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff) -#define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f) -#define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff) +/* Used for CPU number allocation and parallel CPU bringup */ +u32 cpuid_to_apicid[] __ro_after_init = { [0 ... NR_CPUS - 1] = BAD_APICID, }; + +/* Bitmaps to mark registered APICs at each topology domain */ +static struct { DECLARE_BITMAP(map, MAX_LOCAL_APIC); } apic_maps[TOPO_MAX_DOMAIN] __ro_after_init; + +/* + * Keep track of assigned, disabled and rejected CPUs. Present assigned + * with 1 as CPU #0 is reserved for the boot CPU. + */ +static struct { + unsigned int nr_assigned_cpus; + unsigned int nr_disabled_cpus; + unsigned int nr_rejected_cpus; + u32 boot_cpu_apic_id; + u32 real_bsp_apic_id; +} topo_info __ro_after_init = { + .nr_assigned_cpus = 1, + .boot_cpu_apic_id = BAD_APICID, + .real_bsp_apic_id = BAD_APICID, +}; -unsigned int __max_die_per_package __read_mostly = 1; -EXPORT_SYMBOL(__max_die_per_package); +#define domain_weight(_dom) bitmap_weight(apic_maps[_dom].map, MAX_LOCAL_APIC) + +bool arch_match_cpu_phys_id(int cpu, u64 phys_id) +{ + return phys_id == (u64)cpuid_to_apicid[cpu]; +} #ifdef CONFIG_SMP +static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) +{ + if (!(apicid & (__max_threads_per_core - 1))) + cpumask_set_cpu(cpu, &__cpu_primary_thread_mask); +} +#else +static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { } +#endif + /* - * Check if given CPUID extended topology "leaf" is implemented + * Convert the APIC ID to a domain level ID by masking out the low bits + * below the domain level @dom. */ -static int check_extended_topology_leaf(int leaf) +static inline u32 topo_apicid(u32 apicid, enum x86_topology_domains dom) +{ + if (dom == TOPO_SMT_DOMAIN) + return apicid; + return apicid & (UINT_MAX << x86_topo_system.dom_shifts[dom - 1]); +} + +static int topo_lookup_cpuid(u32 apic_id) { - unsigned int eax, ebx, ecx, edx; + int i; - cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); + /* CPU# to APICID mapping is persistent once it is established */ + for (i = 0; i < topo_info.nr_assigned_cpus; i++) { + if (cpuid_to_apicid[i] == apic_id) + return i; + } + return -ENODEV; +} - if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE)) - return -1; +static __init int topo_get_cpunr(u32 apic_id) +{ + int cpu = topo_lookup_cpuid(apic_id); - return 0; + if (cpu >= 0) + return cpu; + + return topo_info.nr_assigned_cpus++; } -/* - * Return best CPUID Extended Topology Leaf supported + +static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id) +{ +#if defined(CONFIG_SMP) || defined(CONFIG_X86_64) + early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id; + early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id; +#endif + set_cpu_present(cpu, true); +} + +static __init bool check_for_real_bsp(u32 apic_id) +{ + /* + * There is no real good way to detect whether this a kdump() + * kernel, but except on the Voyager SMP monstrosity which is not + * longer supported, the real BSP APIC ID is the first one which is + * enumerated by firmware. That allows to detect whether the boot + * CPU is the real BSP. If it is not, then do not register the APIC + * because sending INIT to the real BSP would reset the whole + * system. + * + * The first APIC ID which is enumerated by firmware is detectable + * because the boot CPU APIC ID is registered before that without + * invoking this code. + */ + if (topo_info.real_bsp_apic_id != BAD_APICID) + return false; + + if (apic_id == topo_info.boot_cpu_apic_id) { + topo_info.real_bsp_apic_id = apic_id; + return false; + } + + pr_warn("Boot CPU APIC ID not the first enumerated APIC ID: %x > %x\n", + topo_info.boot_cpu_apic_id, apic_id); + pr_warn("Crash kernel detected. Disabling real BSP to prevent machine INIT\n"); + + topo_info.real_bsp_apic_id = apic_id; + return true; +} + +static unsigned int topo_unit_count(u32 lvlid, enum x86_topology_domains at_level, + unsigned long *map) +{ + unsigned int id, end, cnt = 0; + + /* Calculate the exclusive end */ + end = lvlid + (1U << x86_topo_system.dom_shifts[at_level]); + + /* Unfortunately there is no bitmap_weight_range() */ + for (id = find_next_bit(map, end, lvlid); id < end; id = find_next_bit(map, end, ++id)) + cnt++; + return cnt; +} + +static __init void topo_register_apic(u32 apic_id, u32 acpi_id, bool present) +{ + int cpu, dom; + + if (present) { + set_bit(apic_id, phys_cpu_present_map); + + /* + * Double registration is valid in case of the boot CPU + * APIC because that is registered before the enumeration + * of the APICs via firmware parsers or VM guest + * mechanisms. + */ + if (apic_id == topo_info.boot_cpu_apic_id) + cpu = 0; + else + cpu = topo_get_cpunr(apic_id); + + cpuid_to_apicid[cpu] = apic_id; + topo_set_cpuids(cpu, apic_id, acpi_id); + } else { + u32 pkgid = topo_apicid(apic_id, TOPO_PKG_DOMAIN); + + /* + * Check for present APICs in the same package when running + * on bare metal. Allow the bogosity in a guest. + */ + if (hypervisor_is_type(X86_HYPER_NATIVE) && + topo_unit_count(pkgid, TOPO_PKG_DOMAIN, phys_cpu_present_map)) { + pr_info_once("Ignoring hot-pluggable APIC ID %x in present package.\n", + apic_id); + topo_info.nr_rejected_cpus++; + return; + } + + topo_info.nr_disabled_cpus++; + } + + /* + * Register present and possible CPUs in the domain + * maps. cpu_possible_map will be updated in + * topology_init_possible_cpus() after enumeration is done. + */ + for (dom = TOPO_SMT_DOMAIN; dom < TOPO_MAX_DOMAIN; dom++) + set_bit(topo_apicid(apic_id, dom), apic_maps[dom].map); +} + +/** + * topology_register_apic - Register an APIC in early topology maps + * @apic_id: The APIC ID to set up + * @acpi_id: The ACPI ID associated to the APIC + * @present: True if the corresponding CPU is present */ -static int detect_extended_topology_leaf(struct cpuinfo_x86 *c) +void __init topology_register_apic(u32 apic_id, u32 acpi_id, bool present) { - if (c->cpuid_level >= 0x1f) { - if (check_extended_topology_leaf(0x1f) == 0) - return 0x1f; + if (apic_id >= MAX_LOCAL_APIC) { + pr_err_once("APIC ID %x exceeds kernel limit of: %x\n", apic_id, MAX_LOCAL_APIC - 1); + topo_info.nr_rejected_cpus++; + return; + } + + if (check_for_real_bsp(apic_id)) { + topo_info.nr_rejected_cpus++; + return; } - if (c->cpuid_level >= 0xb) { - if (check_extended_topology_leaf(0xb) == 0) - return 0xb; + /* CPU numbers exhausted? */ + if (apic_id != topo_info.boot_cpu_apic_id && topo_info.nr_assigned_cpus >= nr_cpu_ids) { + pr_warn_once("CPU limit of %d reached. Ignoring further CPUs\n", nr_cpu_ids); + topo_info.nr_rejected_cpus++; + return; } - return -1; + topo_register_apic(apic_id, acpi_id, present); +} + +/** + * topology_register_boot_apic - Register the boot CPU APIC + * @apic_id: The APIC ID to set up + * + * Separate so CPU #0 can be assigned + */ +void __init topology_register_boot_apic(u32 apic_id) +{ + WARN_ON_ONCE(topo_info.boot_cpu_apic_id != BAD_APICID); + + topo_info.boot_cpu_apic_id = apic_id; + topo_register_apic(apic_id, CPU_ACPIID_INVALID, true); +} + +/** + * topology_get_logical_id - Retrieve the logical ID at a given topology domain level + * @apicid: The APIC ID for which to lookup the logical ID + * @at_level: The topology domain level to use + * + * @apicid must be a full APIC ID, not the normalized variant. It's valid to have + * all bits below the domain level specified by @at_level to be clear. So both + * real APIC IDs and backshifted normalized APIC IDs work correctly. + * + * Returns: + * - >= 0: The requested logical ID + * - -ERANGE: @apicid is out of range + * - -ENODEV: @apicid is not registered + */ +int topology_get_logical_id(u32 apicid, enum x86_topology_domains at_level) +{ + /* Remove the bits below @at_level to get the proper level ID of @apicid */ + unsigned int lvlid = topo_apicid(apicid, at_level); + + if (lvlid >= MAX_LOCAL_APIC) + return -ERANGE; + if (!test_bit(lvlid, apic_maps[at_level].map)) + return -ENODEV; + /* Get the number of set bits before @lvlid. */ + return bitmap_weight(apic_maps[at_level].map, lvlid); +} +EXPORT_SYMBOL_GPL(topology_get_logical_id); + +/** + * topology_unit_count - Retrieve the count of specified units at a given topology domain level + * @apicid: The APIC ID which specifies the search range + * @which_units: The domain level specifying the units to count + * @at_level: The domain level at which @which_units have to be counted + * + * This returns the number of possible units according to the enumerated + * information. + * + * E.g. topology_count_units(apicid, TOPO_CORE_DOMAIN, TOPO_PKG_DOMAIN) + * counts the number of possible cores in the package to which @apicid + * belongs. + * + * @at_level must obviously be greater than @which_level to produce useful + * results. If @at_level is equal to @which_units the result is + * unsurprisingly 1. If @at_level is less than @which_units the results + * is by definition undefined and the function returns 0. + */ +unsigned int topology_unit_count(u32 apicid, enum x86_topology_domains which_units, + enum x86_topology_domains at_level) +{ + /* Remove the bits below @at_level to get the proper level ID of @apicid */ + unsigned int lvlid = topo_apicid(apicid, at_level); + + if (lvlid >= MAX_LOCAL_APIC) + return 0; + if (!test_bit(lvlid, apic_maps[at_level].map)) + return 0; + if (which_units > at_level) + return 0; + if (which_units == at_level) + return 1; + return topo_unit_count(lvlid, at_level, apic_maps[which_units].map); +} + +#ifdef CONFIG_ACPI_HOTPLUG_CPU +/** + * topology_hotplug_apic - Handle a physical hotplugged APIC after boot + * @apic_id: The APIC ID to set up + * @acpi_id: The ACPI ID associated to the APIC + */ +int topology_hotplug_apic(u32 apic_id, u32 acpi_id) +{ + int cpu; + + if (apic_id >= MAX_LOCAL_APIC) + return -EINVAL; + + /* Reject if the APIC ID was not registered during enumeration. */ + if (!test_bit(apic_id, apic_maps[TOPO_SMT_DOMAIN].map)) + return -ENODEV; + + cpu = topo_lookup_cpuid(apic_id); + if (cpu < 0) + return -ENOSPC; + + set_bit(apic_id, phys_cpu_present_map); + topo_set_cpuids(cpu, apic_id, acpi_id); + cpu_mark_primary_thread(cpu, apic_id); + return cpu; +} + +/** + * topology_hotunplug_apic - Remove a physical hotplugged APIC after boot + * @cpu: The CPU number for which the APIC ID is removed + */ +void topology_hotunplug_apic(unsigned int cpu) +{ + u32 apic_id = cpuid_to_apicid[cpu]; + + if (apic_id == BAD_APICID) + return; + + per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID; + clear_bit(apic_id, phys_cpu_present_map); + set_cpu_present(cpu, false); } #endif -int detect_extended_topology_early(struct cpuinfo_x86 *c) +#ifdef CONFIG_X86_LOCAL_APIC +static unsigned int max_possible_cpus __initdata = NR_CPUS; + +/** + * topology_apply_cmdline_limits_early - Apply topology command line limits early + * + * Ensure that command line limits are in effect before firmware parsing + * takes place. + */ +void __init topology_apply_cmdline_limits_early(void) { -#ifdef CONFIG_SMP - unsigned int eax, ebx, ecx, edx; - int leaf; + unsigned int possible = nr_cpu_ids; - leaf = detect_extended_topology_leaf(c); - if (leaf < 0) - return -1; + /* 'maxcpus=0' 'nosmp' 'nolapic' 'disableapic' 'noapic' */ + if (!setup_max_cpus || ioapic_is_disabled || apic_is_disabled) + possible = 1; - set_cpu_cap(c, X86_FEATURE_XTOPOLOGY); + /* 'possible_cpus=N' */ + possible = min_t(unsigned int, max_possible_cpus, possible); + + if (possible < nr_cpu_ids) { + pr_info("Limiting to %u possible CPUs\n", possible); + set_nr_cpu_ids(possible); + } +} - cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); +static __init bool restrict_to_up(void) +{ + if (!smp_found_config || ioapic_is_disabled) + return true; /* - * initial apic id, which also represents 32-bit extended x2apic id. + * XEN PV is special as it does not advertise the local APIC + * properly, but provides a fake topology for it so that the + * infrastructure works. So don't apply the restrictions vs. APIC + * here. */ - c->topo.initial_apicid = edx; - smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx)); -#endif - return 0; + if (xen_pv_domain()) + return false; + + return apic_is_disabled; } -/* - * Check for extended topology enumeration cpuid leaf, and if it - * exists, use it for populating initial_apicid and cpu topology - * detection. - */ -int detect_extended_topology(struct cpuinfo_x86 *c) +void __init topology_init_possible_cpus(void) { -#ifdef CONFIG_SMP - unsigned int eax, ebx, ecx, edx, sub_index; - unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width; - unsigned int core_select_mask, core_level_siblings; - unsigned int die_select_mask, die_level_siblings; - unsigned int pkg_mask_width; - bool die_level_present = false; - int leaf; - - leaf = detect_extended_topology_leaf(c); - if (leaf < 0) - return -1; + unsigned int assigned = topo_info.nr_assigned_cpus; + unsigned int disabled = topo_info.nr_disabled_cpus; + unsigned int cnta, cntb, cpu, allowed = 1; + unsigned int total = assigned + disabled; + u32 apicid, firstid; /* - * Populate HT related information from sub-leaf level 0. + * If there was no APIC registered, then fake one so that the + * topology bitmap is populated. That ensures that the code below + * is valid and the various query interfaces can be used + * unconditionally. This does not affect the actual APIC code in + * any way because either the local APIC address has not been + * registered or the local APIC was disabled on the command line. */ - cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); - c->topo.initial_apicid = edx; - core_level_siblings = LEVEL_MAX_SIBLINGS(ebx); - smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx)); - core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); - die_level_siblings = LEVEL_MAX_SIBLINGS(ebx); - pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); - - sub_index = 1; - while (true) { - cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx); + if (topo_info.boot_cpu_apic_id == BAD_APICID) + topology_register_boot_apic(0); - /* - * Check for the Core type in the implemented sub leaves. - */ - if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) { - core_level_siblings = LEVEL_MAX_SIBLINGS(ebx); - core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); - die_level_siblings = core_level_siblings; - die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); - } - if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) { - die_level_present = true; - die_level_siblings = LEVEL_MAX_SIBLINGS(ebx); - die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); + if (!restrict_to_up()) { + if (WARN_ON_ONCE(assigned > nr_cpu_ids)) { + disabled += assigned - nr_cpu_ids; + assigned = nr_cpu_ids; } + allowed = min_t(unsigned int, total, nr_cpu_ids); + } - if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE) - pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); - else - break; + if (total > allowed) + pr_warn("%u possible CPUs exceed the limit of %u\n", total, allowed); - sub_index++; - } + assigned = min_t(unsigned int, allowed, assigned); + disabled = allowed - assigned; - core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width; - die_select_mask = (~(-1 << die_plus_mask_width)) >> - core_plus_mask_width; + topo_info.nr_assigned_cpus = assigned; + topo_info.nr_disabled_cpus = disabled; - c->topo.core_id = apic->phys_pkg_id(c->topo.initial_apicid, - ht_mask_width) & core_select_mask; + total_cpus = allowed; + set_nr_cpu_ids(allowed); - if (die_level_present) { - c->topo.die_id = apic->phys_pkg_id(c->topo.initial_apicid, - core_plus_mask_width) & die_select_mask; - } + cnta = domain_weight(TOPO_PKG_DOMAIN); + cntb = domain_weight(TOPO_DIE_DOMAIN); + __max_logical_packages = cnta; + __max_dies_per_package = 1U << (get_count_order(cntb) - get_count_order(cnta)); + + pr_info("Max. logical packages: %3u\n", cnta); + pr_info("Max. logical dies: %3u\n", cntb); + pr_info("Max. dies per package: %3u\n", __max_dies_per_package); - c->topo.pkg_id = apic->phys_pkg_id(c->topo.initial_apicid, pkg_mask_width); + cnta = domain_weight(TOPO_CORE_DOMAIN); + cntb = domain_weight(TOPO_SMT_DOMAIN); /* - * Reinit the apicid, now that we have extended initial_apicid. + * Can't use order delta here as order(cnta) can be equal + * order(cntb) even if cnta != cntb. */ - c->topo.apicid = apic->phys_pkg_id(c->topo.initial_apicid, 0); + __max_threads_per_core = DIV_ROUND_UP(cntb, cnta); + pr_info("Max. threads per core: %3u\n", __max_threads_per_core); - c->x86_max_cores = (core_level_siblings / smp_num_siblings); - __max_die_per_package = (die_level_siblings / core_level_siblings); -#endif + firstid = find_first_bit(apic_maps[TOPO_SMT_DOMAIN].map, MAX_LOCAL_APIC); + __num_cores_per_package = topology_unit_count(firstid, TOPO_CORE_DOMAIN, TOPO_PKG_DOMAIN); + pr_info("Num. cores per package: %3u\n", __num_cores_per_package); + __num_threads_per_package = topology_unit_count(firstid, TOPO_SMT_DOMAIN, TOPO_PKG_DOMAIN); + pr_info("Num. threads per package: %3u\n", __num_threads_per_package); + + pr_info("Allowing %u present CPUs plus %u hotplug CPUs\n", assigned, disabled); + if (topo_info.nr_rejected_cpus) + pr_info("Rejected CPUs %u\n", topo_info.nr_rejected_cpus); + + init_cpu_present(cpumask_of(0)); + init_cpu_possible(cpumask_of(0)); + + /* Assign CPU numbers to non-present CPUs */ + for (apicid = 0; disabled; disabled--, apicid++) { + apicid = find_next_andnot_bit(apic_maps[TOPO_SMT_DOMAIN].map, phys_cpu_present_map, + MAX_LOCAL_APIC, apicid); + if (apicid >= MAX_LOCAL_APIC) + break; + cpuid_to_apicid[topo_info.nr_assigned_cpus++] = apicid; + } + + for (cpu = 0; cpu < allowed; cpu++) { + apicid = cpuid_to_apicid[cpu]; + + set_cpu_possible(cpu, true); + + if (apicid == BAD_APICID) + continue; + + cpu_mark_primary_thread(cpu, apicid); + set_cpu_present(cpu, test_bit(apicid, phys_cpu_present_map)); + } +} + +/* + * Late SMP disable after sizing CPU masks when APIC/IOAPIC setup failed. + */ +void __init topology_reset_possible_cpus_up(void) +{ + init_cpu_present(cpumask_of(0)); + init_cpu_possible(cpumask_of(0)); + + bitmap_zero(phys_cpu_present_map, MAX_LOCAL_APIC); + if (topo_info.boot_cpu_apic_id != BAD_APICID) + set_bit(topo_info.boot_cpu_apic_id, phys_cpu_present_map); +} + +static int __init setup_possible_cpus(char *str) +{ + get_option(&str, &max_possible_cpus); return 0; } +early_param("possible_cpus", setup_possible_cpus); +#endif |