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 /** 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, unsigned long align, 101 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn) 102 { 103 const unsigned long goal = __pa(MAX_DMA_ADDRESS); 104 #ifdef CONFIG_NUMA 105 int node = cpu_to_nd_fn(cpu); 106 void *ptr; 107 108 if (!node_online(node) || !NODE_DATA(node)) { 109 ptr = memblock_alloc_from(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 = memblock_alloc_try_nid(size, align, goal, 116 MEMBLOCK_ALLOC_ACCESSIBLE, 117 node); 118 119 pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n", 120 cpu, size, node, __pa(ptr)); 121 } 122 return ptr; 123 #else 124 return memblock_alloc_from(size, align, goal); 125 #endif 126 } 127 128 /* 129 * Helpers for first chunk memory allocation 130 */ 131 static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align, 132 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn) 133 { 134 return pcpu_alloc_bootmem(cpu, size, align, cpu_to_nd_fn); 135 } 136 137 static void __init pcpu_fc_free(void *ptr, size_t size) 138 { 139 memblock_free(ptr, size); 140 } 141 142 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 143 { 144 #ifdef CONFIG_NUMA 145 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 146 return LOCAL_DISTANCE; 147 else 148 return REMOTE_DISTANCE; 149 #else 150 return LOCAL_DISTANCE; 151 #endif 152 } 153 154 static int __init pcpu_cpu_to_node(int cpu) 155 { 156 return early_cpu_to_node(cpu); 157 } 158 159 static void __init pcpup_populate_pte(unsigned long addr) 160 { 161 populate_extra_pte(addr); 162 } 163 164 static inline void setup_percpu_segment(int cpu) 165 { 166 #ifdef CONFIG_X86_32 167 struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu), 168 0xFFFFF); 169 170 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S); 171 #endif 172 } 173 174 void __init setup_per_cpu_areas(void) 175 { 176 unsigned int cpu; 177 unsigned long delta; 178 int rc; 179 180 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n", 181 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 182 183 /* 184 * Allocate percpu area. Embedding allocator is our favorite; 185 * however, on NUMA configurations, it can result in very 186 * sparse unit mapping and vmalloc area isn't spacious enough 187 * on 32bit. Use page in that case. 188 */ 189 #ifdef CONFIG_X86_32 190 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 191 pcpu_chosen_fc = PCPU_FC_PAGE; 192 #endif 193 rc = -EINVAL; 194 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 195 const size_t dyn_size = PERCPU_MODULE_RESERVE + 196 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 197 size_t atom_size; 198 199 /* 200 * On 64bit, use PMD_SIZE for atom_size so that embedded 201 * percpu areas are aligned to PMD. This, in the future, 202 * can also allow using PMD mappings in vmalloc area. Use 203 * PAGE_SIZE on 32bit as vmalloc space is highly contended 204 * and large vmalloc area allocs can easily fail. 205 */ 206 #ifdef CONFIG_X86_64 207 atom_size = PMD_SIZE; 208 #else 209 atom_size = PAGE_SIZE; 210 #endif 211 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 212 dyn_size, atom_size, 213 pcpu_cpu_distance, 214 pcpu_cpu_to_node, 215 pcpu_fc_alloc, pcpu_fc_free); 216 if (rc < 0) 217 pr_warn("%s allocator failed (%d), falling back to page size\n", 218 pcpu_fc_names[pcpu_chosen_fc], rc); 219 } 220 if (rc < 0) 221 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 222 pcpu_cpu_to_node, 223 pcpu_fc_alloc, pcpu_fc_free, 224 pcpup_populate_pte); 225 if (rc < 0) 226 panic("cannot initialize percpu area (err=%d)", rc); 227 228 /* alrighty, percpu areas up and running */ 229 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 230 for_each_possible_cpu(cpu) { 231 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 232 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 233 per_cpu(cpu_number, cpu) = cpu; 234 setup_percpu_segment(cpu); 235 /* 236 * Copy data used in early init routines from the 237 * initial arrays to the per cpu data areas. These 238 * arrays then become expendable and the *_early_ptr's 239 * are zeroed indicating that the static arrays are 240 * gone. 241 */ 242 #ifdef CONFIG_X86_LOCAL_APIC 243 per_cpu(x86_cpu_to_apicid, cpu) = 244 early_per_cpu_map(x86_cpu_to_apicid, cpu); 245 per_cpu(x86_bios_cpu_apicid, cpu) = 246 early_per_cpu_map(x86_bios_cpu_apicid, cpu); 247 per_cpu(x86_cpu_to_acpiid, cpu) = 248 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 249 #endif 250 #ifdef CONFIG_X86_32 251 per_cpu(x86_cpu_to_logical_apicid, cpu) = 252 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu); 253 #endif 254 #ifdef CONFIG_NUMA 255 per_cpu(x86_cpu_to_node_map, cpu) = 256 early_per_cpu_map(x86_cpu_to_node_map, cpu); 257 /* 258 * Ensure that the boot cpu numa_node is correct when the boot 259 * cpu is on a node that doesn't have memory installed. 260 * Also cpu_up() will call cpu_to_node() for APs when 261 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 262 * up later with c_init aka intel_init/amd_init. 263 * So set them all (boot cpu and all APs). 264 */ 265 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 266 #endif 267 /* 268 * Up to this point, the boot CPU has been using .init.data 269 * area. Reload any changed state for the boot CPU. 270 */ 271 if (!cpu) 272 switch_to_new_gdt(cpu); 273 } 274 275 /* indicate the early static arrays will soon be gone */ 276 #ifdef CONFIG_X86_LOCAL_APIC 277 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 278 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 279 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 280 #endif 281 #ifdef CONFIG_X86_32 282 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL; 283 #endif 284 #ifdef CONFIG_NUMA 285 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 286 #endif 287 288 /* Setup node to cpumask map */ 289 setup_node_to_cpumask_map(); 290 291 /* Setup cpu initialized, callin, callout masks */ 292 setup_cpu_local_masks(); 293 294 /* 295 * Sync back kernel address range again. We already did this in 296 * setup_arch(), but percpu data also needs to be available in 297 * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to 298 * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available 299 * there too. 300 * 301 * FIXME: Can the later sync in setup_cpu_entry_areas() replace 302 * this call? 303 */ 304 sync_initial_page_table(); 305 } 306