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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
32DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
33EXPORT_PER_CPU_SYMBOL(this_cpu_off);
34
35unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = {
36 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
37};
38EXPORT_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 */
64static 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
84static 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
96static int __init pcpu_cpu_to_node(int cpu)
97{
98 return early_cpu_to_node(cpu);
99}
100
101void __init pcpu_populate_pte(unsigned long addr)
102{
103 populate_extra_pte(addr);
104}
105
106static inline void setup_percpu_segment(int cpu)
107{
108#ifdef CONFIG_X86_32
109 struct desc_struct d = GDT_ENTRY_INIT(DESC_DATA32,
110 per_cpu_offset(cpu), 0xFFFFF);
111
112 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
113#endif
114}
115
116void __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_cpu_to_acpiid, cpu) =
185 early_per_cpu_map(x86_cpu_to_acpiid, cpu);
186#endif
187#ifdef CONFIG_NUMA
188 per_cpu(x86_cpu_to_node_map, cpu) =
189 early_per_cpu_map(x86_cpu_to_node_map, cpu);
190 /*
191 * Ensure that the boot cpu numa_node is correct when the boot
192 * cpu is on a node that doesn't have memory installed.
193 * Also cpu_up() will call cpu_to_node() for APs when
194 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
195 * up later with c_init aka intel_init/amd_init.
196 * So set them all (boot cpu and all APs).
197 */
198 set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
199#endif
200 /*
201 * Up to this point, the boot CPU has been using .init.data
202 * area. Reload any changed state for the boot CPU.
203 */
204 if (!cpu)
205 switch_gdt_and_percpu_base(cpu);
206 }
207
208 /* indicate the early static arrays will soon be gone */
209#ifdef CONFIG_X86_LOCAL_APIC
210 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
211 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
212#endif
213#ifdef CONFIG_NUMA
214 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
215#endif
216
217 /* Setup node to cpumask map */
218 setup_node_to_cpumask_map();
219
220 /* Setup cpu initialized, callin, callout masks */
221 setup_cpu_local_masks();
222
223 /*
224 * Sync back kernel address range again. We already did this in
225 * setup_arch(), but percpu data also needs to be available in
226 * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
227 * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
228 * there too.
229 *
230 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
231 * this call?
232 */
233 sync_initial_page_table();
234}
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
24DEFINE_PER_CPU(int, cpu_number);
25EXPORT_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
33DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
34EXPORT_PER_CPU_SYMBOL(this_cpu_off);
35
36unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
37 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
38};
39EXPORT_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 */
65static 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 */
98static 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 */
127static 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
132static void __init pcpu_fc_free(void *ptr, size_t size)
133{
134 free_bootmem(__pa(ptr), size);
135}
136
137static 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
149static void __init pcpup_populate_pte(unsigned long addr)
150{
151 populate_extra_pte(addr);
152}
153
154static 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
167void __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 atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
189 const size_t dyn_size = PERCPU_MODULE_RESERVE +
190 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
191
192 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
193 dyn_size, atom_size,
194 pcpu_cpu_distance,
195 pcpu_fc_alloc, pcpu_fc_free);
196 if (rc < 0)
197 pr_warning("%s allocator failed (%d), falling back to page size\n",
198 pcpu_fc_names[pcpu_chosen_fc], rc);
199 }
200 if (rc < 0)
201 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
202 pcpu_fc_alloc, pcpu_fc_free,
203 pcpup_populate_pte);
204 if (rc < 0)
205 panic("cannot initialize percpu area (err=%d)", rc);
206
207 /* alrighty, percpu areas up and running */
208 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
209 for_each_possible_cpu(cpu) {
210 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
211 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
212 per_cpu(cpu_number, cpu) = cpu;
213 setup_percpu_segment(cpu);
214 setup_stack_canary_segment(cpu);
215 /*
216 * Copy data used in early init routines from the
217 * initial arrays to the per cpu data areas. These
218 * arrays then become expendable and the *_early_ptr's
219 * are zeroed indicating that the static arrays are
220 * gone.
221 */
222#ifdef CONFIG_X86_LOCAL_APIC
223 per_cpu(x86_cpu_to_apicid, cpu) =
224 early_per_cpu_map(x86_cpu_to_apicid, cpu);
225 per_cpu(x86_bios_cpu_apicid, cpu) =
226 early_per_cpu_map(x86_bios_cpu_apicid, cpu);
227#endif
228#ifdef CONFIG_X86_32
229 per_cpu(x86_cpu_to_logical_apicid, cpu) =
230 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
231#endif
232#ifdef CONFIG_X86_64
233 per_cpu(irq_stack_ptr, cpu) =
234 per_cpu(irq_stack_union.irq_stack, cpu) +
235 IRQ_STACK_SIZE - 64;
236#endif
237#ifdef CONFIG_NUMA
238 per_cpu(x86_cpu_to_node_map, cpu) =
239 early_per_cpu_map(x86_cpu_to_node_map, cpu);
240 /*
241 * Ensure that the boot cpu numa_node is correct when the boot
242 * cpu is on a node that doesn't have memory installed.
243 * Also cpu_up() will call cpu_to_node() for APs when
244 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
245 * up later with c_init aka intel_init/amd_init.
246 * So set them all (boot cpu and all APs).
247 */
248 set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
249#endif
250 /*
251 * Up to this point, the boot CPU has been using .init.data
252 * area. Reload any changed state for the boot CPU.
253 */
254 if (!cpu)
255 switch_to_new_gdt(cpu);
256 }
257
258 /* indicate the early static arrays will soon be gone */
259#ifdef CONFIG_X86_LOCAL_APIC
260 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
261 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
262#endif
263#ifdef CONFIG_X86_32
264 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
265#endif
266#ifdef CONFIG_NUMA
267 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
268#endif
269
270 /* Setup node to cpumask map */
271 setup_node_to_cpumask_map();
272
273 /* Setup cpu initialized, callin, callout masks */
274 setup_cpu_local_masks();
275}