Loading...
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/bootmem.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
26DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
27EXPORT_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
35DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
36EXPORT_PER_CPU_SYMBOL(this_cpu_off);
37
38unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = {
39 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
40};
41EXPORT_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 */
67static 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 */
100static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
101 unsigned long align)
102{
103 const unsigned long goal = __pa(MAX_DMA_ADDRESS);
104#ifdef CONFIG_NEED_MULTIPLE_NODES
105 int node = early_cpu_to_node(cpu);
106 void *ptr;
107
108 if (!node_online(node) || !NODE_DATA(node)) {
109 ptr = __alloc_bootmem_nopanic(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 = __alloc_bootmem_node_nopanic(NODE_DATA(node),
116 size, align, goal);
117 pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
118 cpu, size, node, __pa(ptr));
119 }
120 return ptr;
121#else
122 return __alloc_bootmem_nopanic(size, align, goal);
123#endif
124}
125
126/*
127 * Helpers for first chunk memory allocation
128 */
129static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
130{
131 return pcpu_alloc_bootmem(cpu, size, align);
132}
133
134static void __init pcpu_fc_free(void *ptr, size_t size)
135{
136 free_bootmem(__pa(ptr), size);
137}
138
139static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
140{
141#ifdef CONFIG_NEED_MULTIPLE_NODES
142 if (early_cpu_to_node(from) == early_cpu_to_node(to))
143 return LOCAL_DISTANCE;
144 else
145 return REMOTE_DISTANCE;
146#else
147 return LOCAL_DISTANCE;
148#endif
149}
150
151static void __init pcpup_populate_pte(unsigned long addr)
152{
153 populate_extra_pte(addr);
154}
155
156static inline void setup_percpu_segment(int cpu)
157{
158#ifdef CONFIG_X86_32
159 struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu),
160 0xFFFFF);
161
162 write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
163#endif
164}
165
166void __init setup_per_cpu_areas(void)
167{
168 unsigned int cpu;
169 unsigned long delta;
170 int rc;
171
172 pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%d\n",
173 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
174
175 /*
176 * Allocate percpu area. Embedding allocator is our favorite;
177 * however, on NUMA configurations, it can result in very
178 * sparse unit mapping and vmalloc area isn't spacious enough
179 * on 32bit. Use page in that case.
180 */
181#ifdef CONFIG_X86_32
182 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
183 pcpu_chosen_fc = PCPU_FC_PAGE;
184#endif
185 rc = -EINVAL;
186 if (pcpu_chosen_fc != PCPU_FC_PAGE) {
187 const size_t dyn_size = PERCPU_MODULE_RESERVE +
188 PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
189 size_t atom_size;
190
191 /*
192 * On 64bit, use PMD_SIZE for atom_size so that embedded
193 * percpu areas are aligned to PMD. This, in the future,
194 * can also allow using PMD mappings in vmalloc area. Use
195 * PAGE_SIZE on 32bit as vmalloc space is highly contended
196 * and large vmalloc area allocs can easily fail.
197 */
198#ifdef CONFIG_X86_64
199 atom_size = PMD_SIZE;
200#else
201 atom_size = PAGE_SIZE;
202#endif
203 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
204 dyn_size, atom_size,
205 pcpu_cpu_distance,
206 pcpu_fc_alloc, pcpu_fc_free);
207 if (rc < 0)
208 pr_warning("%s allocator failed (%d), falling back to page size\n",
209 pcpu_fc_names[pcpu_chosen_fc], rc);
210 }
211 if (rc < 0)
212 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
213 pcpu_fc_alloc, pcpu_fc_free,
214 pcpup_populate_pte);
215 if (rc < 0)
216 panic("cannot initialize percpu area (err=%d)", rc);
217
218 /* alrighty, percpu areas up and running */
219 delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
220 for_each_possible_cpu(cpu) {
221 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
222 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
223 per_cpu(cpu_number, cpu) = cpu;
224 setup_percpu_segment(cpu);
225 setup_stack_canary_segment(cpu);
226 /*
227 * Copy data used in early init routines from the
228 * initial arrays to the per cpu data areas. These
229 * arrays then become expendable and the *_early_ptr's
230 * are zeroed indicating that the static arrays are
231 * gone.
232 */
233#ifdef CONFIG_X86_LOCAL_APIC
234 per_cpu(x86_cpu_to_apicid, cpu) =
235 early_per_cpu_map(x86_cpu_to_apicid, cpu);
236 per_cpu(x86_bios_cpu_apicid, cpu) =
237 early_per_cpu_map(x86_bios_cpu_apicid, cpu);
238 per_cpu(x86_cpu_to_acpiid, cpu) =
239 early_per_cpu_map(x86_cpu_to_acpiid, cpu);
240#endif
241#ifdef CONFIG_X86_32
242 per_cpu(x86_cpu_to_logical_apicid, cpu) =
243 early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
244#endif
245#ifdef CONFIG_X86_64
246 per_cpu(irq_stack_ptr, cpu) =
247 per_cpu(irq_stack_union.irq_stack, cpu) +
248 IRQ_STACK_SIZE;
249#endif
250#ifdef CONFIG_NUMA
251 per_cpu(x86_cpu_to_node_map, cpu) =
252 early_per_cpu_map(x86_cpu_to_node_map, cpu);
253 /*
254 * Ensure that the boot cpu numa_node is correct when the boot
255 * cpu is on a node that doesn't have memory installed.
256 * Also cpu_up() will call cpu_to_node() for APs when
257 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
258 * up later with c_init aka intel_init/amd_init.
259 * So set them all (boot cpu and all APs).
260 */
261 set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
262#endif
263 /*
264 * Up to this point, the boot CPU has been using .init.data
265 * area. Reload any changed state for the boot CPU.
266 */
267 if (!cpu)
268 switch_to_new_gdt(cpu);
269 }
270
271 /* indicate the early static arrays will soon be gone */
272#ifdef CONFIG_X86_LOCAL_APIC
273 early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
274 early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
275 early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
276#endif
277#ifdef CONFIG_X86_32
278 early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
279#endif
280#ifdef CONFIG_NUMA
281 early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
282#endif
283
284 /* Setup node to cpumask map */
285 setup_node_to_cpumask_map();
286
287 /* Setup cpu initialized, callin, callout masks */
288 setup_cpu_local_masks();
289
290 /*
291 * Sync back kernel address range again. We already did this in
292 * setup_arch(), but percpu data also needs to be available in
293 * the smpboot asm. We can't reliably pick up percpu mappings
294 * using vmalloc_fault(), because exception dispatch needs
295 * percpu data.
296 *
297 * FIXME: Can the later sync in setup_cpu_entry_areas() replace
298 * this call?
299 */
300 sync_initial_page_table();
301}
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}