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/bootmem.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_NEED_MULTIPLE_NODES 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 /** 88 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu 89 * @cpu: cpu to allocate for 90 * @size: size allocation in bytes 91 * @align: alignment 92 * 93 * Allocate @size bytes aligned at @align for cpu @cpu. This wrapper 94 * does the right thing for NUMA regardless of the current 95 * configuration. 96 * 97 * RETURNS: 98 * Pointer to the allocated area on success, NULL on failure. 99 */ 100 static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size, 101 unsigned long align) 102 { 103 const unsigned long goal = __pa(MAX_DMA_ADDRESS); 104 #ifdef CONFIG_NEED_MULTIPLE_NODES 105 int node = early_cpu_to_node(cpu); 106 void *ptr; 107 108 if (!node_online(node) || !NODE_DATA(node)) { 109 ptr = __alloc_bootmem_nopanic(size, align, goal); 110 pr_info("cpu %d has no node %d or node-local memory\n", 111 cpu, node); 112 pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n", 113 cpu, size, __pa(ptr)); 114 } else { 115 ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node), 116 size, align, goal); 117 pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n", 118 cpu, size, node, __pa(ptr)); 119 } 120 return ptr; 121 #else 122 return __alloc_bootmem_nopanic(size, align, goal); 123 #endif 124 } 125 126 /* 127 * Helpers for first chunk memory allocation 128 */ 129 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align) 130 { 131 return pcpu_alloc_bootmem(cpu, size, align); 132 } 133 134 static void __init pcpu_fc_free(void *ptr, size_t size) 135 { 136 free_bootmem(__pa(ptr), size); 137 } 138 139 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 140 { 141 #ifdef CONFIG_NEED_MULTIPLE_NODES 142 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 143 return LOCAL_DISTANCE; 144 else 145 return REMOTE_DISTANCE; 146 #else 147 return LOCAL_DISTANCE; 148 #endif 149 } 150 151 static void __init pcpup_populate_pte(unsigned long addr) 152 { 153 populate_extra_pte(addr); 154 } 155 156 static inline void setup_percpu_segment(int cpu) 157 { 158 #ifdef CONFIG_X86_32 159 struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu), 160 0xFFFFF); 161 162 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S); 163 #endif 164 } 165 166 void __init setup_per_cpu_areas(void) 167 { 168 unsigned int cpu; 169 unsigned long delta; 170 int rc; 171 172 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%d\n", 173 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 174 175 /* 176 * Allocate percpu area. Embedding allocator is our favorite; 177 * however, on NUMA configurations, it can result in very 178 * sparse unit mapping and vmalloc area isn't spacious enough 179 * on 32bit. Use page in that case. 180 */ 181 #ifdef CONFIG_X86_32 182 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 183 pcpu_chosen_fc = PCPU_FC_PAGE; 184 #endif 185 rc = -EINVAL; 186 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 187 const size_t dyn_size = PERCPU_MODULE_RESERVE + 188 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 189 size_t atom_size; 190 191 /* 192 * On 64bit, use PMD_SIZE for atom_size so that embedded 193 * percpu areas are aligned to PMD. This, in the future, 194 * can also allow using PMD mappings in vmalloc area. Use 195 * PAGE_SIZE on 32bit as vmalloc space is highly contended 196 * and large vmalloc area allocs can easily fail. 197 */ 198 #ifdef CONFIG_X86_64 199 atom_size = PMD_SIZE; 200 #else 201 atom_size = PAGE_SIZE; 202 #endif 203 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 204 dyn_size, atom_size, 205 pcpu_cpu_distance, 206 pcpu_fc_alloc, pcpu_fc_free); 207 if (rc < 0) 208 pr_warning("%s allocator failed (%d), falling back to page size\n", 209 pcpu_fc_names[pcpu_chosen_fc], rc); 210 } 211 if (rc < 0) 212 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 213 pcpu_fc_alloc, pcpu_fc_free, 214 pcpup_populate_pte); 215 if (rc < 0) 216 panic("cannot initialize percpu area (err=%d)", rc); 217 218 /* alrighty, percpu areas up and running */ 219 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 220 for_each_possible_cpu(cpu) { 221 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 222 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 223 per_cpu(cpu_number, cpu) = cpu; 224 setup_percpu_segment(cpu); 225 setup_stack_canary_segment(cpu); 226 /* 227 * Copy data used in early init routines from the 228 * initial arrays to the per cpu data areas. These 229 * arrays then become expendable and the *_early_ptr's 230 * are zeroed indicating that the static arrays are 231 * gone. 232 */ 233 #ifdef CONFIG_X86_LOCAL_APIC 234 per_cpu(x86_cpu_to_apicid, cpu) = 235 early_per_cpu_map(x86_cpu_to_apicid, cpu); 236 per_cpu(x86_bios_cpu_apicid, cpu) = 237 early_per_cpu_map(x86_bios_cpu_apicid, cpu); 238 per_cpu(x86_cpu_to_acpiid, cpu) = 239 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 240 #endif 241 #ifdef CONFIG_X86_32 242 per_cpu(x86_cpu_to_logical_apicid, cpu) = 243 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu); 244 #endif 245 #ifdef CONFIG_X86_64 246 per_cpu(irq_stack_ptr, cpu) = 247 per_cpu(irq_stack_union.irq_stack, cpu) + 248 IRQ_STACK_SIZE; 249 #endif 250 #ifdef CONFIG_NUMA 251 per_cpu(x86_cpu_to_node_map, cpu) = 252 early_per_cpu_map(x86_cpu_to_node_map, cpu); 253 /* 254 * Ensure that the boot cpu numa_node is correct when the boot 255 * cpu is on a node that doesn't have memory installed. 256 * Also cpu_up() will call cpu_to_node() for APs when 257 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 258 * up later with c_init aka intel_init/amd_init. 259 * So set them all (boot cpu and all APs). 260 */ 261 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 262 #endif 263 /* 264 * Up to this point, the boot CPU has been using .init.data 265 * area. Reload any changed state for the boot CPU. 266 */ 267 if (!cpu) 268 switch_to_new_gdt(cpu); 269 } 270 271 /* indicate the early static arrays will soon be gone */ 272 #ifdef CONFIG_X86_LOCAL_APIC 273 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 274 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 275 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 276 #endif 277 #ifdef CONFIG_X86_32 278 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL; 279 #endif 280 #ifdef CONFIG_NUMA 281 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 282 #endif 283 284 /* Setup node to cpumask map */ 285 setup_node_to_cpumask_map(); 286 287 /* Setup cpu initialized, callin, callout masks */ 288 setup_cpu_local_masks(); 289 290 #ifdef CONFIG_X86_32 291 /* 292 * Sync back kernel address range again. We already did this in 293 * setup_arch(), but percpu data also needs to be available in 294 * the smpboot asm. We can't reliably pick up percpu mappings 295 * using vmalloc_fault(), because exception dispatch needs 296 * percpu data. 297 */ 298 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 299 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 300 KERNEL_PGD_PTRS); 301 302 /* 303 * sync back low identity map too. It is used for example 304 * in the 32-bit EFI stub. 305 */ 306 clone_pgd_range(initial_page_table, 307 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 308 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 309 #endif 310 } 311