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 <linux/stackprotector.h> 15 #include <asm/sections.h> 16 #include <asm/processor.h> 17 #include <asm/desc.h> 18 #include <asm/setup.h> 19 #include <asm/mpspec.h> 20 #include <asm/apicdef.h> 21 #include <asm/highmem.h> 22 #include <asm/proto.h> 23 #include <asm/cpumask.h> 24 #include <asm/cpu.h> 25 26 #ifdef CONFIG_X86_64 27 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load) 28 #else 29 #define BOOT_PERCPU_OFFSET 0 30 #endif 31 32 DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET; 33 EXPORT_PER_CPU_SYMBOL(this_cpu_off); 34 35 unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = { 36 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET, 37 }; 38 EXPORT_SYMBOL(__per_cpu_offset); 39 40 /* 41 * On x86_64 symbols referenced from code should be reachable using 42 * 32bit relocations. Reserve space for static percpu variables in 43 * modules so that they are always served from the first chunk which 44 * is located at the percpu segment base. On x86_32, anything can 45 * address anywhere. No need to reserve space in the first chunk. 46 */ 47 #ifdef CONFIG_X86_64 48 #define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE 49 #else 50 #define PERCPU_FIRST_CHUNK_RESERVE 0 51 #endif 52 53 #ifdef CONFIG_X86_32 54 /** 55 * pcpu_need_numa - determine percpu allocation needs to consider NUMA 56 * 57 * If NUMA is not configured or there is only one NUMA node available, 58 * there is no reason to consider NUMA. This function determines 59 * whether percpu allocation should consider NUMA or not. 60 * 61 * RETURNS: 62 * true if NUMA should be considered; otherwise, false. 63 */ 64 static bool __init pcpu_need_numa(void) 65 { 66 #ifdef CONFIG_NUMA 67 pg_data_t *last = NULL; 68 unsigned int cpu; 69 70 for_each_possible_cpu(cpu) { 71 int node = early_cpu_to_node(cpu); 72 73 if (node_online(node) && NODE_DATA(node) && 74 last && last != NODE_DATA(node)) 75 return true; 76 77 last = NODE_DATA(node); 78 } 79 #endif 80 return false; 81 } 82 #endif 83 84 static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) 85 { 86 #ifdef CONFIG_NUMA 87 if (early_cpu_to_node(from) == early_cpu_to_node(to)) 88 return LOCAL_DISTANCE; 89 else 90 return REMOTE_DISTANCE; 91 #else 92 return LOCAL_DISTANCE; 93 #endif 94 } 95 96 static int __init pcpu_cpu_to_node(int cpu) 97 { 98 return early_cpu_to_node(cpu); 99 } 100 101 void __init pcpu_populate_pte(unsigned long addr) 102 { 103 populate_extra_pte(addr); 104 } 105 106 static inline void setup_percpu_segment(int cpu) 107 { 108 #ifdef CONFIG_X86_32 109 struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu), 110 0xFFFFF); 111 112 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S); 113 #endif 114 } 115 116 void __init setup_per_cpu_areas(void) 117 { 118 unsigned int cpu; 119 unsigned long delta; 120 int rc; 121 122 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n", 123 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); 124 125 /* 126 * Allocate percpu area. Embedding allocator is our favorite; 127 * however, on NUMA configurations, it can result in very 128 * sparse unit mapping and vmalloc area isn't spacious enough 129 * on 32bit. Use page in that case. 130 */ 131 #ifdef CONFIG_X86_32 132 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) 133 pcpu_chosen_fc = PCPU_FC_PAGE; 134 #endif 135 rc = -EINVAL; 136 if (pcpu_chosen_fc != PCPU_FC_PAGE) { 137 const size_t dyn_size = PERCPU_MODULE_RESERVE + 138 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; 139 size_t atom_size; 140 141 /* 142 * On 64bit, use PMD_SIZE for atom_size so that embedded 143 * percpu areas are aligned to PMD. This, in the future, 144 * can also allow using PMD mappings in vmalloc area. Use 145 * PAGE_SIZE on 32bit as vmalloc space is highly contended 146 * and large vmalloc area allocs can easily fail. 147 */ 148 #ifdef CONFIG_X86_64 149 atom_size = PMD_SIZE; 150 #else 151 atom_size = PAGE_SIZE; 152 #endif 153 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 154 dyn_size, atom_size, 155 pcpu_cpu_distance, 156 pcpu_cpu_to_node); 157 if (rc < 0) 158 pr_warn("%s allocator failed (%d), falling back to page size\n", 159 pcpu_fc_names[pcpu_chosen_fc], rc); 160 } 161 if (rc < 0) 162 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, 163 pcpu_cpu_to_node); 164 if (rc < 0) 165 panic("cannot initialize percpu area (err=%d)", rc); 166 167 /* alrighty, percpu areas up and running */ 168 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; 169 for_each_possible_cpu(cpu) { 170 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; 171 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); 172 per_cpu(pcpu_hot.cpu_number, cpu) = cpu; 173 setup_percpu_segment(cpu); 174 /* 175 * Copy data used in early init routines from the 176 * initial arrays to the per cpu data areas. These 177 * arrays then become expendable and the *_early_ptr's 178 * are zeroed indicating that the static arrays are 179 * gone. 180 */ 181 #ifdef CONFIG_X86_LOCAL_APIC 182 per_cpu(x86_cpu_to_apicid, cpu) = 183 early_per_cpu_map(x86_cpu_to_apicid, cpu); 184 per_cpu(x86_bios_cpu_apicid, cpu) = 185 early_per_cpu_map(x86_bios_cpu_apicid, cpu); 186 per_cpu(x86_cpu_to_acpiid, cpu) = 187 early_per_cpu_map(x86_cpu_to_acpiid, cpu); 188 #endif 189 #ifdef CONFIG_X86_32 190 per_cpu(x86_cpu_to_logical_apicid, cpu) = 191 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu); 192 #endif 193 #ifdef CONFIG_NUMA 194 per_cpu(x86_cpu_to_node_map, cpu) = 195 early_per_cpu_map(x86_cpu_to_node_map, cpu); 196 /* 197 * Ensure that the boot cpu numa_node is correct when the boot 198 * cpu is on a node that doesn't have memory installed. 199 * Also cpu_up() will call cpu_to_node() for APs when 200 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set 201 * up later with c_init aka intel_init/amd_init. 202 * So set them all (boot cpu and all APs). 203 */ 204 set_cpu_numa_node(cpu, early_cpu_to_node(cpu)); 205 #endif 206 /* 207 * Up to this point, the boot CPU has been using .init.data 208 * area. Reload any changed state for the boot CPU. 209 */ 210 if (!cpu) 211 switch_gdt_and_percpu_base(cpu); 212 } 213 214 /* indicate the early static arrays will soon be gone */ 215 #ifdef CONFIG_X86_LOCAL_APIC 216 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; 217 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; 218 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL; 219 #endif 220 #ifdef CONFIG_X86_32 221 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL; 222 #endif 223 #ifdef CONFIG_NUMA 224 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL; 225 #endif 226 227 /* Setup node to cpumask map */ 228 setup_node_to_cpumask_map(); 229 230 /* Setup cpu initialized, callin, callout masks */ 231 setup_cpu_local_masks(); 232 233 /* 234 * Sync back kernel address range again. We already did this in 235 * setup_arch(), but percpu data also needs to be available in 236 * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to 237 * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available 238 * there too. 239 * 240 * FIXME: Can the later sync in setup_cpu_entry_areas() replace 241 * this call? 242 */ 243 sync_initial_page_table(); 244 } 245