1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 2 3 #include <linux/kernel.h> 4 #include <linux/export.h> 5 #include <linux/init.h> 6 #include <linux/bootmem.h> 7 #include <linux/percpu.h> 8 #include <linux/kexec.h> 9 #include <linux/crash_dump.h> 10 #include <linux/smp.h> 11 #include <linux/topology.h> 12 #include <linux/pfn.h> 13 #include <asm/sections.h> 14 #include <asm/processor.h> 15 #include <asm/desc.h> 16 #include <asm/setup.h> 17 #include <asm/mpspec.h> 18 #include <asm/apicdef.h> 19 #include <asm/highmem.h> 20 #include <asm/proto.h> 21 #include <asm/cpumask.h> 22 #include <asm/cpu.h> 23 #include <asm/stackprotector.h> 24 25 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number); 26 EXPORT_PER_CPU_SYMBOL(cpu_number); 27 28 #ifdef CONFIG_X86_64 29 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load) 30 #else 31 #define BOOT_PERCPU_OFFSET 0 32 #endif 33 34 DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; 35 EXPORT_PER_CPU_SYMBOL(this_cpu_off); 36 37 unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = { 38 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET, 39 }; 40 EXPORT_SYMBOL(__per_cpu_offset); 41 42 /* 43 * On x86_64 symbols referenced from code should be reachable using 44 * 32bit relocations. Reserve space for static percpu variables in 45 * modules so that they are always served from the first chunk which 46 * is located at the percpu segment base. On x86_32, anything can 47 * address anywhere. No need to reserve space in the first chunk. 48 */ 49 #ifdef CONFIG_X86_64 50 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE 51 #else 52 #define PERCPU_FIRST_CHUNK_RESERVE 0 53 #endif 54 55 #ifdef CONFIG_X86_32 56 /** 57 * pcpu_need_numa - determine percpu allocation needs to consider NUMA 58 * 59 * If NUMA is not configured or there is only one NUMA node available, 60 * there is no reason to consider NUMA. This function determines 61 * whether percpu allocation should consider NUMA or not. 62 * 63 * RETURNS: 64 * true if NUMA should be considered; otherwise, false. 65 */ 66 static bool __init pcpu_need_numa(void) 67 { 68 #ifdef CONFIG_NEED_MULTIPLE_NODES 69 pg_data_t *last = NULL; 70 unsigned int cpu; 71 72 for_each_possible_cpu(cpu) { 73 int node = early_cpu_to_node(cpu); 74 75 if (node_online(node) && NODE_DATA(node) && 76 last && last != NODE_DATA(node)) 77 return true; 78 79 last = NODE_DATA(node); 80 } 81 #endif 82 return false; 83 } 84 #endif 85 86 /** 87 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu 88 * @cpu: cpu to allocate for 89 * @size: size allocation in bytes 90 * @align: alignment 91 * 92 * Allocate @size bytes aligned at @align for cpu @cpu. This wrapper 93 * does the right thing for NUMA regardless of the current 94 * configuration. 95 * 96 * RETURNS: 97 * Pointer to the allocated area on success, NULL on failure. 98 */ 99 static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size, 100 unsigned long align) 101 { 102 const unsigned long goal = __pa(MAX_DMA_ADDRESS); 103 #ifdef CONFIG_NEED_MULTIPLE_NODES 104 int node = early_cpu_to_node(cpu); 105 void *ptr; 106 107 if (!node_online(node) || !NODE_DATA(node)) { 108 ptr = __alloc_bootmem_nopanic(size, align, goal); 109 pr_info("cpu %d has no node %d or node-local memory\n", 110 cpu, node); 111 pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n", 112 cpu, size, __pa(ptr)); 113 } else { 114 ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node), 115 size, align, goal); 116 pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n", 117 cpu, size, node, __pa(ptr)); 118 } 119 return ptr; 120 #else 121 return __alloc_bootmem_nopanic(size, align, goal); 122 #endif 123 } 124 125 /* 126 * Helpers for first chunk memory allocation 127 */ 128 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align) 129 { 130 return pcpu_alloc_bootmem(cpu, size, align); 131 } 132 133 static void __init pcpu_fc_free(void *ptr, size_t size) 134 { 135 free_bootmem(__pa(ptr), size); 136 } 137 138 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 139 { 140 #ifdef CONFIG_NEED_MULTIPLE_NODES 141 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 142 return LOCAL_DISTANCE; 143 else 144 return REMOTE_DISTANCE; 145 #else 146 return LOCAL_DISTANCE; 147 #endif 148 } 149 150 static void __init pcpup_populate_pte(unsigned long addr) 151 { 152 populate_extra_pte(addr); 153 } 154 155 static inline void setup_percpu_segment(int cpu) 156 { 157 #ifdef CONFIG_X86_32 158 struct desc_struct gdt; 159 160 pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF, 161 0x2 | DESCTYPE_S, 0x8); 162 gdt.s = 1; 163 write_gdt_entry(get_cpu_gdt_rw(cpu), 164 GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S); 165 #endif 166 } 167 168 void __init setup_per_cpu_areas(void) 169 { 170 unsigned int cpu; 171 unsigned long delta; 172 int rc; 173 174 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n", 175 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 176 177 /* 178 * Allocate percpu area. Embedding allocator is our favorite; 179 * however, on NUMA configurations, it can result in very 180 * sparse unit mapping and vmalloc area isn't spacious enough 181 * on 32bit. Use page in that case. 182 */ 183 #ifdef CONFIG_X86_32 184 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 185 pcpu_chosen_fc = PCPU_FC_PAGE; 186 #endif 187 rc = -EINVAL; 188 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 189 const size_t dyn_size = PERCPU_MODULE_RESERVE + 190 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 191 size_t atom_size; 192 193 /* 194 * On 64bit, use PMD_SIZE for atom_size so that embedded 195 * percpu areas are aligned to PMD. This, in the future, 196 * can also allow using PMD mappings in vmalloc area. Use 197 * PAGE_SIZE on 32bit as vmalloc space is highly contended 198 * and large vmalloc area allocs can easily fail. 199 */ 200 #ifdef CONFIG_X86_64 201 atom_size = PMD_SIZE; 202 #else 203 atom_size = PAGE_SIZE; 204 #endif 205 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 206 dyn_size, atom_size, 207 pcpu_cpu_distance, 208 pcpu_fc_alloc, pcpu_fc_free); 209 if (rc < 0) 210 pr_warning("%s allocator failed (%d), falling back to page size\n", 211 pcpu_fc_names[pcpu_chosen_fc], rc); 212 } 213 if (rc < 0) 214 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 215 pcpu_fc_alloc, pcpu_fc_free, 216 pcpup_populate_pte); 217 if (rc < 0) 218 panic("cannot initialize percpu area (err=%d)", rc); 219 220 /* alrighty, percpu areas up and running */ 221 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 222 for_each_possible_cpu(cpu) { 223 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 224 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 225 per_cpu(cpu_number, cpu) = cpu; 226 setup_percpu_segment(cpu); 227 setup_stack_canary_segment(cpu); 228 /* 229 * Copy data used in early init routines from the 230 * initial arrays to the per cpu data areas. These 231 * arrays then become expendable and the *_early_ptr's 232 * are zeroed indicating that the static arrays are 233 * gone. 234 */ 235 #ifdef CONFIG_X86_LOCAL_APIC 236 per_cpu(x86_cpu_to_apicid, cpu) = 237 early_per_cpu_map(x86_cpu_to_apicid, cpu); 238 per_cpu(x86_bios_cpu_apicid, cpu) = 239 early_per_cpu_map(x86_bios_cpu_apicid, cpu); 240 per_cpu(x86_cpu_to_acpiid, cpu) = 241 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 242 #endif 243 #ifdef CONFIG_X86_32 244 per_cpu(x86_cpu_to_logical_apicid, cpu) = 245 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu); 246 #endif 247 #ifdef CONFIG_X86_64 248 per_cpu(irq_stack_ptr, cpu) = 249 per_cpu(irq_stack_union.irq_stack, cpu) + 250 IRQ_STACK_SIZE; 251 #endif 252 #ifdef CONFIG_NUMA 253 per_cpu(x86_cpu_to_node_map, cpu) = 254 early_per_cpu_map(x86_cpu_to_node_map, cpu); 255 /* 256 * Ensure that the boot cpu numa_node is correct when the boot 257 * cpu is on a node that doesn't have memory installed. 258 * Also cpu_up() will call cpu_to_node() for APs when 259 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 260 * up later with c_init aka intel_init/amd_init. 261 * So set them all (boot cpu and all APs). 262 */ 263 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 264 #endif 265 /* 266 * Up to this point, the boot CPU has been using .init.data 267 * area. Reload any changed state for the boot CPU. 268 */ 269 if (!cpu) 270 switch_to_new_gdt(cpu); 271 } 272 273 /* indicate the early static arrays will soon be gone */ 274 #ifdef CONFIG_X86_LOCAL_APIC 275 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 276 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 277 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 278 #endif 279 #ifdef CONFIG_X86_32 280 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL; 281 #endif 282 #ifdef CONFIG_NUMA 283 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 284 #endif 285 286 /* Setup node to cpumask map */ 287 setup_node_to_cpumask_map(); 288 289 /* Setup cpu initialized, callin, callout masks */ 290 setup_cpu_local_masks(); 291 292 #ifdef CONFIG_X86_32 293 /* 294 * Sync back kernel address range. We want to make sure that 295 * all kernel mappings, including percpu mappings, are available 296 * in the smpboot asm. We can't reliably pick up percpu 297 * mappings using vmalloc_fault(), because exception dispatch 298 * needs percpu data. 299 */ 300 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 301 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 302 KERNEL_PGD_PTRS); 303 304 /* 305 * sync back low identity map too. It is used for example 306 * in the 32-bit EFI stub. 307 */ 308 clone_pgd_range(initial_page_table, 309 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 310 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 311 #endif 312 } 313