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 <asm/sections.h> 15 #include <asm/processor.h> 16 #include <asm/desc.h> 17 #include <asm/setup.h> 18 #include <asm/mpspec.h> 19 #include <asm/apicdef.h> 20 #include <asm/highmem.h> 21 #include <asm/proto.h> 22 #include <asm/cpumask.h> 23 #include <asm/cpu.h> 24 #include <asm/stackprotector.h> 25 26 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number); 27 EXPORT_PER_CPU_SYMBOL(cpu_number); 28 29 #ifdef CONFIG_X86_64 30 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load) 31 #else 32 #define BOOT_PERCPU_OFFSET 0 33 #endif 34 35 DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; 36 EXPORT_PER_CPU_SYMBOL(this_cpu_off); 37 38 unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = { 39 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET, 40 }; 41 EXPORT_SYMBOL(__per_cpu_offset); 42 43 /* 44 * On x86_64 symbols referenced from code should be reachable using 45 * 32bit relocations. Reserve space for static percpu variables in 46 * modules so that they are always served from the first chunk which 47 * is located at the percpu segment base. On x86_32, anything can 48 * address anywhere. No need to reserve space in the first chunk. 49 */ 50 #ifdef CONFIG_X86_64 51 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE 52 #else 53 #define PERCPU_FIRST_CHUNK_RESERVE 0 54 #endif 55 56 #ifdef CONFIG_X86_32 57 /** 58 * pcpu_need_numa - determine percpu allocation needs to consider NUMA 59 * 60 * If NUMA is not configured or there is only one NUMA node available, 61 * there is no reason to consider NUMA. This function determines 62 * whether percpu allocation should consider NUMA or not. 63 * 64 * RETURNS: 65 * true if NUMA should be considered; otherwise, false. 66 */ 67 static bool __init pcpu_need_numa(void) 68 { 69 #ifdef CONFIG_NUMA 70 pg_data_t *last = NULL; 71 unsigned int cpu; 72 73 for_each_possible_cpu(cpu) { 74 int node = early_cpu_to_node(cpu); 75 76 if (node_online(node) && NODE_DATA(node) && 77 last && last != NODE_DATA(node)) 78 return true; 79 80 last = NODE_DATA(node); 81 } 82 #endif 83 return false; 84 } 85 #endif 86 87 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 88 { 89 #ifdef CONFIG_NUMA 90 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 91 return LOCAL_DISTANCE; 92 else 93 return REMOTE_DISTANCE; 94 #else 95 return LOCAL_DISTANCE; 96 #endif 97 } 98 99 static int __init pcpu_cpu_to_node(int cpu) 100 { 101 return early_cpu_to_node(cpu); 102 } 103 104 void __init pcpu_populate_pte(unsigned long addr) 105 { 106 populate_extra_pte(addr); 107 } 108 109 static inline void setup_percpu_segment(int cpu) 110 { 111 #ifdef CONFIG_X86_32 112 struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu), 113 0xFFFFF); 114 115 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S); 116 #endif 117 } 118 119 void __init setup_per_cpu_areas(void) 120 { 121 unsigned int cpu; 122 unsigned long delta; 123 int rc; 124 125 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n", 126 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 127 128 /* 129 * Allocate percpu area. Embedding allocator is our favorite; 130 * however, on NUMA configurations, it can result in very 131 * sparse unit mapping and vmalloc area isn't spacious enough 132 * on 32bit. Use page in that case. 133 */ 134 #ifdef CONFIG_X86_32 135 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 136 pcpu_chosen_fc = PCPU_FC_PAGE; 137 #endif 138 rc = -EINVAL; 139 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 140 const size_t dyn_size = PERCPU_MODULE_RESERVE + 141 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 142 size_t atom_size; 143 144 /* 145 * On 64bit, use PMD_SIZE for atom_size so that embedded 146 * percpu areas are aligned to PMD. This, in the future, 147 * can also allow using PMD mappings in vmalloc area. Use 148 * PAGE_SIZE on 32bit as vmalloc space is highly contended 149 * and large vmalloc area allocs can easily fail. 150 */ 151 #ifdef CONFIG_X86_64 152 atom_size = PMD_SIZE; 153 #else 154 atom_size = PAGE_SIZE; 155 #endif 156 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 157 dyn_size, atom_size, 158 pcpu_cpu_distance, 159 pcpu_cpu_to_node); 160 if (rc < 0) 161 pr_warn("%s allocator failed (%d), falling back to page size\n", 162 pcpu_fc_names[pcpu_chosen_fc], rc); 163 } 164 if (rc < 0) 165 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 166 pcpu_cpu_to_node); 167 if (rc < 0) 168 panic("cannot initialize percpu area (err=%d)", rc); 169 170 /* alrighty, percpu areas up and running */ 171 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 172 for_each_possible_cpu(cpu) { 173 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 174 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 175 per_cpu(cpu_number, cpu) = cpu; 176 setup_percpu_segment(cpu); 177 /* 178 * Copy data used in early init routines from the 179 * initial arrays to the per cpu data areas. These 180 * arrays then become expendable and the *_early_ptr's 181 * are zeroed indicating that the static arrays are 182 * gone. 183 */ 184 #ifdef CONFIG_X86_LOCAL_APIC 185 per_cpu(x86_cpu_to_apicid, cpu) = 186 early_per_cpu_map(x86_cpu_to_apicid, cpu); 187 per_cpu(x86_bios_cpu_apicid, cpu) = 188 early_per_cpu_map(x86_bios_cpu_apicid, cpu); 189 per_cpu(x86_cpu_to_acpiid, cpu) = 190 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 191 #endif 192 #ifdef CONFIG_X86_32 193 per_cpu(x86_cpu_to_logical_apicid, cpu) = 194 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu); 195 #endif 196 #ifdef CONFIG_NUMA 197 per_cpu(x86_cpu_to_node_map, cpu) = 198 early_per_cpu_map(x86_cpu_to_node_map, cpu); 199 /* 200 * Ensure that the boot cpu numa_node is correct when the boot 201 * cpu is on a node that doesn't have memory installed. 202 * Also cpu_up() will call cpu_to_node() for APs when 203 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 204 * up later with c_init aka intel_init/amd_init. 205 * So set them all (boot cpu and all APs). 206 */ 207 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 208 #endif 209 /* 210 * Up to this point, the boot CPU has been using .init.data 211 * area. Reload any changed state for the boot CPU. 212 */ 213 if (!cpu) 214 switch_to_new_gdt(cpu); 215 } 216 217 /* indicate the early static arrays will soon be gone */ 218 #ifdef CONFIG_X86_LOCAL_APIC 219 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 220 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 221 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 222 #endif 223 #ifdef CONFIG_X86_32 224 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL; 225 #endif 226 #ifdef CONFIG_NUMA 227 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 228 #endif 229 230 /* Setup node to cpumask map */ 231 setup_node_to_cpumask_map(); 232 233 /* Setup cpu initialized, callin, callout masks */ 234 setup_cpu_local_masks(); 235 236 /* 237 * Sync back kernel address range again. We already did this in 238 * setup_arch(), but percpu data also needs to be available in 239 * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to 240 * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available 241 * there too. 242 * 243 * FIXME: Can the later sync in setup_cpu_entry_areas() replace 244 * this call? 245 */ 246 sync_initial_page_table(); 247 } 248