Line data Source code
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_NEED_MULTIPLE_NODES
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 1 : static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
101 : unsigned long align)
102 : {
103 1 : const unsigned long goal = __pa(MAX_DMA_ADDRESS);
104 : #ifdef CONFIG_NEED_MULTIPLE_NODES
105 1 : int node = early_cpu_to_node(cpu);
106 1 : void *ptr;
107 :
108 1 : if (!node_online(node) || !NODE_DATA(node)) {
109 0 : ptr = memblock_alloc_from(size, align, goal);
110 0 : pr_info("cpu %d has no node %d or node-local memory\n",
111 : cpu, node);
112 0 : pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
113 : cpu, size, __pa(ptr));
114 : } else {
115 1 : ptr = memblock_alloc_try_nid(size, align, goal,
116 : MEMBLOCK_ALLOC_ACCESSIBLE,
117 : node);
118 :
119 1 : pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
120 : cpu, size, node, __pa(ptr));
121 : }
122 1 : 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 1 : static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
132 : {
133 1 : return pcpu_alloc_bootmem(cpu, size, align);
134 : }
135 :
136 4 : static void __init pcpu_fc_free(void *ptr, size_t size)
137 : {
138 4 : memblock_free(__pa(ptr), size);
139 4 : }
140 :
141 6 : static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
142 : {
143 : #ifdef CONFIG_NEED_MULTIPLE_NODES
144 6 : if (early_cpu_to_node(from) == early_cpu_to_node(to))
145 : return LOCAL_DISTANCE;
146 : else
147 0 : return REMOTE_DISTANCE;
148 : #else
149 : return LOCAL_DISTANCE;
150 : #endif
151 : }
152 :
153 0 : static void __init pcpup_populate_pte(unsigned long addr)
154 : {
155 0 : populate_extra_pte(addr);
156 0 : }
157 :
158 4 : static inline void setup_percpu_segment(int cpu)
159 : {
160 : #ifdef CONFIG_X86_32
161 : struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu),
162 : 0xFFFFF);
163 :
164 : write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
165 : #endif
166 4 : }
167 :
168 1 : void __init setup_per_cpu_areas(void)
169 : {
170 1 : unsigned int cpu;
171 1 : unsigned long delta;
172 1 : int rc;
173 :
174 1 : pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\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 1 : rc = -EINVAL;
188 1 : if (pcpu_chosen_fc != PCPU_FC_PAGE) {
189 1 : const size_t dyn_size = PERCPU_MODULE_RESERVE +
190 : PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
191 1 : 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 1 : atom_size = PMD_SIZE;
202 : #else
203 : atom_size = PAGE_SIZE;
204 : #endif
205 1 : 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 1 : if (rc < 0)
210 0 : pr_warn("%s allocator failed (%d), falling back to page size\n",
211 : pcpu_fc_names[pcpu_chosen_fc], rc);
212 : }
213 1 : if (rc < 0)
214 0 : rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
215 : pcpu_fc_alloc, pcpu_fc_free,
216 : pcpup_populate_pte);
217 1 : if (rc < 0)
218 0 : panic("cannot initialize percpu area (err=%d)", rc);
219 :
220 : /* alrighty, percpu areas up and running */
221 1 : delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
222 6 : for_each_possible_cpu(cpu) {
223 4 : per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
224 4 : per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
225 4 : per_cpu(cpu_number, cpu) = cpu;
226 4 : setup_percpu_segment(cpu);
227 4 : 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 4 : per_cpu(x86_cpu_to_apicid, cpu) =
237 4 : early_per_cpu_map(x86_cpu_to_apicid, cpu);
238 4 : per_cpu(x86_bios_cpu_apicid, cpu) =
239 4 : early_per_cpu_map(x86_bios_cpu_apicid, cpu);
240 4 : per_cpu(x86_cpu_to_acpiid, cpu) =
241 4 : 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_NUMA
248 4 : per_cpu(x86_cpu_to_node_map, cpu) =
249 4 : early_per_cpu_map(x86_cpu_to_node_map, cpu);
250 : /*
251 : * Ensure that the boot cpu numa_node is correct when the boot
252 : * cpu is on a node that doesn't have memory installed.
253 : * Also cpu_up() will call cpu_to_node() for APs when
254 : * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
255 : * up later with c_init aka intel_init/amd_init.
256 : * So set them all (boot cpu and all APs).
257 : */
258 4 : set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
259 : #endif
260 : /*
261 : * Up to this point, the boot CPU has been using .init.data
262 : * area. Reload any changed state for the boot CPU.
263 : */
264 4 : if (!cpu)
265 1 : switch_to_new_gdt(cpu);
266 : }
267 :
268 : /* indicate the early static arrays will soon be gone */
269 : #ifdef CONFIG_X86_LOCAL_APIC
270 1 : early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
271 1 : early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
272 1 : early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
273 : #endif
274 : #ifdef CONFIG_X86_32
275 : early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
276 : #endif
277 : #ifdef CONFIG_NUMA
278 1 : early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
279 : #endif
280 :
281 : /* Setup node to cpumask map */
282 1 : setup_node_to_cpumask_map();
283 :
284 : /* Setup cpu initialized, callin, callout masks */
285 1 : setup_cpu_local_masks();
286 :
287 : /*
288 : * Sync back kernel address range again. We already did this in
289 : * setup_arch(), but percpu data also needs to be available in
290 : * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
291 : * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
292 : * there too.
293 : *
294 : * FIXME: Can the later sync in setup_cpu_entry_areas() replace
295 : * this call?
296 : */
297 1 : sync_initial_page_table();
298 1 : }
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