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 #ifdef CONFIG_DEBUG_PER_CPU_MAPS 25 # define DBG(fmt, ...) pr_dbg(fmt, ##__VA_ARGS__) 26 #else 27 # define DBG(fmt, ...) do { if (0) pr_dbg(fmt, ##__VA_ARGS__); } while (0) 28 #endif 29 30 DEFINE_PER_CPU(int, cpu_number); 31 EXPORT_PER_CPU_SYMBOL(cpu_number); 32 33 #ifdef CONFIG_X86_64 34 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load) 35 #else 36 #define BOOT_PERCPU_OFFSET 0 37 #endif 38 39 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; 40 EXPORT_PER_CPU_SYMBOL(this_cpu_off); 41 42 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = { 43 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET, 44 }; 45 EXPORT_SYMBOL(__per_cpu_offset); 46 47 /* 48 * On x86_64 symbols referenced from code should be reachable using 49 * 32bit relocations. Reserve space for static percpu variables in 50 * modules so that they are always served from the first chunk which 51 * is located at the percpu segment base. On x86_32, anything can 52 * address anywhere. No need to reserve space in the first chunk. 53 */ 54 #ifdef CONFIG_X86_64 55 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE 56 #else 57 #define PERCPU_FIRST_CHUNK_RESERVE 0 58 #endif 59 60 #ifdef CONFIG_X86_32 61 /** 62 * pcpu_need_numa - determine percpu allocation needs to consider NUMA 63 * 64 * If NUMA is not configured or there is only one NUMA node available, 65 * there is no reason to consider NUMA. This function determines 66 * whether percpu allocation should consider NUMA or not. 67 * 68 * RETURNS: 69 * true if NUMA should be considered; otherwise, false. 70 */ 71 static bool __init pcpu_need_numa(void) 72 { 73 #ifdef CONFIG_NEED_MULTIPLE_NODES 74 pg_data_t *last = NULL; 75 unsigned int cpu; 76 77 for_each_possible_cpu(cpu) { 78 int node = early_cpu_to_node(cpu); 79 80 if (node_online(node) && NODE_DATA(node) && 81 last && last != NODE_DATA(node)) 82 return true; 83 84 last = NODE_DATA(node); 85 } 86 #endif 87 return false; 88 } 89 #endif 90 91 /** 92 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu 93 * @cpu: cpu to allocate for 94 * @size: size allocation in bytes 95 * @align: alignment 96 * 97 * Allocate @size bytes aligned at @align for cpu @cpu. This wrapper 98 * does the right thing for NUMA regardless of the current 99 * configuration. 100 * 101 * RETURNS: 102 * Pointer to the allocated area on success, NULL on failure. 103 */ 104 static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size, 105 unsigned long align) 106 { 107 const unsigned long goal = __pa(MAX_DMA_ADDRESS); 108 #ifdef CONFIG_NEED_MULTIPLE_NODES 109 int node = early_cpu_to_node(cpu); 110 void *ptr; 111 112 if (!node_online(node) || !NODE_DATA(node)) { 113 ptr = __alloc_bootmem_nopanic(size, align, goal); 114 pr_info("cpu %d has no node %d or node-local memory\n", 115 cpu, node); 116 pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n", 117 cpu, size, __pa(ptr)); 118 } else { 119 ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node), 120 size, align, goal); 121 pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n", 122 cpu, size, node, __pa(ptr)); 123 } 124 return ptr; 125 #else 126 return __alloc_bootmem_nopanic(size, align, goal); 127 #endif 128 } 129 130 /* 131 * Helpers for first chunk memory allocation 132 */ 133 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align) 134 { 135 return pcpu_alloc_bootmem(cpu, size, align); 136 } 137 138 static void __init pcpu_fc_free(void *ptr, size_t size) 139 { 140 #ifdef CONFIG_NO_BOOTMEM 141 u64 start = __pa(ptr); 142 u64 end = start + size; 143 free_early_partial(start, end); 144 #else 145 free_bootmem(__pa(ptr), size); 146 #endif 147 } 148 149 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 150 { 151 #ifdef CONFIG_NEED_MULTIPLE_NODES 152 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 153 return LOCAL_DISTANCE; 154 else 155 return REMOTE_DISTANCE; 156 #else 157 return LOCAL_DISTANCE; 158 #endif 159 } 160 161 static void __init pcpup_populate_pte(unsigned long addr) 162 { 163 populate_extra_pte(addr); 164 } 165 166 static inline void setup_percpu_segment(int cpu) 167 { 168 #ifdef CONFIG_X86_32 169 struct desc_struct gdt; 170 171 pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF, 172 0x2 | DESCTYPE_S, 0x8); 173 gdt.s = 1; 174 write_gdt_entry(get_cpu_gdt_table(cpu), 175 GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S); 176 #endif 177 } 178 179 void __init setup_per_cpu_areas(void) 180 { 181 unsigned int cpu; 182 unsigned long delta; 183 int rc; 184 185 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n", 186 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 187 188 /* 189 * Allocate percpu area. Embedding allocator is our favorite; 190 * however, on NUMA configurations, it can result in very 191 * sparse unit mapping and vmalloc area isn't spacious enough 192 * on 32bit. Use page in that case. 193 */ 194 #ifdef CONFIG_X86_32 195 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 196 pcpu_chosen_fc = PCPU_FC_PAGE; 197 #endif 198 rc = -EINVAL; 199 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 200 const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE; 201 const size_t dyn_size = PERCPU_MODULE_RESERVE + 202 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 203 204 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_64 241 per_cpu(irq_stack_ptr, cpu) = 242 per_cpu(irq_stack_union.irq_stack, cpu) + 243 IRQ_STACK_SIZE - 64; 244 #ifdef CONFIG_NUMA 245 per_cpu(x86_cpu_to_node_map, cpu) = 246 early_per_cpu_map(x86_cpu_to_node_map, cpu); 247 #endif 248 #endif 249 /* 250 * Up to this point, the boot CPU has been using .data.init 251 * area. Reload any changed state for the boot CPU. 252 */ 253 if (cpu == boot_cpu_id) 254 switch_to_new_gdt(cpu); 255 } 256 257 /* indicate the early static arrays will soon be gone */ 258 #ifdef CONFIG_X86_LOCAL_APIC 259 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 260 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 261 #endif 262 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA) 263 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 264 #endif 265 266 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA) 267 /* 268 * make sure boot cpu node_number is right, when boot cpu is on the 269 * node that doesn't have mem installed 270 */ 271 per_cpu(node_number, boot_cpu_id) = cpu_to_node(boot_cpu_id); 272 #endif 273 274 /* Setup node to cpumask map */ 275 setup_node_to_cpumask_map(); 276 277 /* Setup cpu initialized, callin, callout masks */ 278 setup_cpu_local_masks(); 279 } 280