diff options
Diffstat (limited to 'arch/x86/kernel/cpu/topology.c')
| -rw-r--r-- | arch/x86/kernel/cpu/topology.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c new file mode 100644 index 000000000..0270925fe --- /dev/null +++ b/arch/x86/kernel/cpu/topology.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Check for extended topology enumeration cpuid leaf 0xb and if it + * exists, use it for populating initial_apicid and cpu topology + * detection. + */ + +#include <linux/cpu.h> +#include <asm/apic.h> +#include <asm/memtype.h> +#include <asm/processor.h> + +#include "cpu.h" + +/* leaf 0xb SMT level */ +#define SMT_LEVEL 0 + +/* extended topology sub-leaf types */ +#define INVALID_TYPE 0 +#define SMT_TYPE 1 +#define CORE_TYPE 2 +#define DIE_TYPE 5 + +#define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff) +#define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f) +#define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff) + +unsigned int __max_die_per_package __read_mostly = 1; +EXPORT_SYMBOL(__max_die_per_package); + +#ifdef CONFIG_SMP +/* + * Check if given CPUID extended topology "leaf" is implemented + */ +static int check_extended_topology_leaf(int leaf) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); + + if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE)) + return -1; + + return 0; +} +/* + * Return best CPUID Extended Topology Leaf supported + */ +static int detect_extended_topology_leaf(struct cpuinfo_x86 *c) +{ + if (c->cpuid_level >= 0x1f) { + if (check_extended_topology_leaf(0x1f) == 0) + return 0x1f; + } + + if (c->cpuid_level >= 0xb) { + if (check_extended_topology_leaf(0xb) == 0) + return 0xb; + } + + return -1; +} +#endif + +int detect_extended_topology_early(struct cpuinfo_x86 *c) +{ +#ifdef CONFIG_SMP + unsigned int eax, ebx, ecx, edx; + int leaf; + + leaf = detect_extended_topology_leaf(c); + if (leaf < 0) + return -1; + + set_cpu_cap(c, X86_FEATURE_XTOPOLOGY); + + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); + /* + * initial apic id, which also represents 32-bit extended x2apic id. + */ + c->initial_apicid = edx; + smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx)); +#endif + return 0; +} + +/* + * 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) +{ +#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; + + /* + * Populate HT related information from sub-leaf level 0. + */ + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); + c->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); + + /* + * 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 (LEAFB_SUBTYPE(ecx) != INVALID_TYPE) + pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); + else + break; + + sub_index++; + } + + core_select_mask = (~(-1 << pkg_mask_width)) >> ht_mask_width; + die_select_mask = (~(-1 << die_plus_mask_width)) >> + core_plus_mask_width; + + c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, + ht_mask_width) & core_select_mask; + + if (die_level_present) { + c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid, + core_plus_mask_width) & die_select_mask; + } + + c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, + pkg_mask_width); + /* + * Reinit the apicid, now that we have extended initial_apicid. + */ + c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); + + c->x86_max_cores = (core_level_siblings / smp_num_siblings); + __max_die_per_package = (die_level_siblings / core_level_siblings); +#endif + return 0; +} |