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