1 // SPDX-License-Identifier: GPL-2.0 2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 3 4 #include <linux/kernel.h> 5 #include <linux/export.h> 6 #include <linux/init.h> 7 #include <linux/memblock.h> 8 #include <linux/percpu.h> 9 #include <linux/kexec.h> 10 #include <linux/crash_dump.h> 11 #include <linux/smp.h> 12 #include <linux/topology.h> 13 #include <linux/pfn.h> 14 #include <linux/stackprotector.h> 15 #include <asm/sections.h> 16 #include <asm/processor.h> 17 #include <asm/desc.h> 18 #include <asm/setup.h> 19 #include <asm/mpspec.h> 20 #include <asm/apicdef.h> 21 #include <asm/highmem.h> 22 #include <asm/proto.h> 23 #include <asm/cpumask.h> 24 #include <asm/cpu.h> 25 26 DEFINE_PER_CPU_CACHE_HOT(int, cpu_number); 27 EXPORT_PER_CPU_SYMBOL(cpu_number); 28 29 DEFINE_PER_CPU_CACHE_HOT(unsigned long, this_cpu_off); 30 EXPORT_PER_CPU_SYMBOL(this_cpu_off); 31 32 unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init; 33 EXPORT_SYMBOL(__per_cpu_offset); 34 35 /* 36 * On x86_64 symbols referenced from code should be reachable using 37 * 32bit relocations. Reserve space for static percpu variables in 38 * modules so that they are always served from the first chunk which 39 * is located at the percpu segment base. On x86_32, anything can 40 * address anywhere. No need to reserve space in the first chunk. 41 */ 42 #ifdef CONFIG_X86_64 43 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE 44 #else 45 #define PERCPU_FIRST_CHUNK_RESERVE 0 46 #endif 47 48 #ifdef CONFIG_X86_32 49 /** 50 * pcpu_need_numa - determine percpu allocation needs to consider NUMA 51 * 52 * If NUMA is not configured or there is only one NUMA node available, 53 * there is no reason to consider NUMA. This function determines 54 * whether percpu allocation should consider NUMA or not. 55 * 56 * RETURNS: 57 * true if NUMA should be considered; otherwise, false. 58 */ 59 static bool __init pcpu_need_numa(void) 60 { 61 #ifdef CONFIG_NUMA 62 pg_data_t *last = NULL; 63 unsigned int cpu; 64 65 for_each_possible_cpu(cpu) { 66 int node = early_cpu_to_node(cpu); 67 68 if (node_online(node) && NODE_DATA(node) && 69 last && last != NODE_DATA(node)) 70 return true; 71 72 last = NODE_DATA(node); 73 } 74 #endif 75 return false; 76 } 77 #endif 78 79 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 80 { 81 #ifdef CONFIG_NUMA 82 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 83 return LOCAL_DISTANCE; 84 else 85 return REMOTE_DISTANCE; 86 #else 87 return LOCAL_DISTANCE; 88 #endif 89 } 90 91 static int __init pcpu_cpu_to_node(int cpu) 92 { 93 return early_cpu_to_node(cpu); 94 } 95 96 void __init pcpu_populate_pte(unsigned long addr) 97 { 98 populate_extra_pte(addr); 99 } 100 101 static inline void setup_percpu_segment(int cpu) 102 { 103 #ifdef CONFIG_X86_32 104 struct desc_struct d = GDT_ENTRY_INIT(DESC_DATA32, 105 per_cpu_offset(cpu), 0xFFFFF); 106 107 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S); 108 #endif 109 } 110 111 void __init setup_per_cpu_areas(void) 112 { 113 unsigned int cpu; 114 unsigned long delta; 115 int rc; 116 117 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n", 118 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 119 120 /* 121 * Allocate percpu area. Embedding allocator is our favorite; 122 * however, on NUMA configurations, it can result in very 123 * sparse unit mapping and vmalloc area isn't spacious enough 124 * on 32bit. Use page in that case. 125 */ 126 #ifdef CONFIG_X86_32 127 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 128 pcpu_chosen_fc = PCPU_FC_PAGE; 129 #endif 130 rc = -EINVAL; 131 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 132 const size_t dyn_size = PERCPU_MODULE_RESERVE + 133 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 134 size_t atom_size; 135 136 /* 137 * On 64bit, use PMD_SIZE for atom_size so that embedded 138 * percpu areas are aligned to PMD. This, in the future, 139 * can also allow using PMD mappings in vmalloc area. Use 140 * PAGE_SIZE on 32bit as vmalloc space is highly contended 141 * and large vmalloc area allocs can easily fail. 142 */ 143 #ifdef CONFIG_X86_64 144 atom_size = PMD_SIZE; 145 #else 146 atom_size = PAGE_SIZE; 147 #endif 148 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 149 dyn_size, atom_size, 150 pcpu_cpu_distance, 151 pcpu_cpu_to_node); 152 if (rc < 0) 153 pr_warn("%s allocator failed (%d), falling back to page size\n", 154 pcpu_fc_names[pcpu_chosen_fc], rc); 155 } 156 if (rc < 0) 157 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 158 pcpu_cpu_to_node); 159 if (rc < 0) 160 panic("cannot initialize percpu area (err=%d)", rc); 161 162 /* alrighty, percpu areas up and running */ 163 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 164 for_each_possible_cpu(cpu) { 165 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 166 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 167 per_cpu(cpu_number, cpu) = cpu; 168 setup_percpu_segment(cpu); 169 /* 170 * Copy data used in early init routines from the 171 * initial arrays to the per cpu data areas. These 172 * arrays then become expendable and the *_early_ptr's 173 * are zeroed indicating that the static arrays are 174 * gone. 175 */ 176 #ifdef CONFIG_X86_LOCAL_APIC 177 per_cpu(x86_cpu_to_apicid, cpu) = 178 early_per_cpu_map(x86_cpu_to_apicid, cpu); 179 per_cpu(x86_cpu_to_acpiid, cpu) = 180 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 181 #endif 182 #ifdef CONFIG_NUMA 183 per_cpu(x86_cpu_to_node_map, cpu) = 184 early_per_cpu_map(x86_cpu_to_node_map, cpu); 185 /* 186 * Ensure that the boot cpu numa_node is correct when the boot 187 * cpu is on a node that doesn't have memory installed. 188 * Also cpu_up() will call cpu_to_node() for APs when 189 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 190 * up later with c_init aka intel_init/amd_init. 191 * So set them all (boot cpu and all APs). 192 */ 193 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 194 #endif 195 /* 196 * Up to this point, the boot CPU has been using .init.data 197 * area. Reload any changed state for the boot CPU. 198 */ 199 if (!cpu) 200 switch_gdt_and_percpu_base(cpu); 201 } 202 203 /* indicate the early static arrays will soon be gone */ 204 #ifdef CONFIG_X86_LOCAL_APIC 205 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 206 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 207 #endif 208 #ifdef CONFIG_NUMA 209 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 210 #endif 211 212 /* Setup node to cpumask map */ 213 setup_node_to_cpumask_map(); 214 215 /* Setup cpu initialized, callin, callout masks */ 216 setup_cpu_local_masks(); 217 218 /* 219 * Sync back kernel address range again. We already did this in 220 * setup_arch(), but percpu data also needs to be available in 221 * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to 222 * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available 223 * there too. 224 * 225 * FIXME: Can the later sync in setup_cpu_entry_areas() replace 226 * this call? 227 */ 228 sync_initial_page_table(); 229 } 230