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
24 DEFINE_PER_CPU(int, cpu_number);
25 EXPORT_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
33 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
34 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
35
36 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
37 [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
38 };
39 EXPORT_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 */
pcpu_need_numa(void)65 static 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 */
pcpu_alloc_bootmem(unsigned int cpu,unsigned long size,unsigned long align)98 static 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 */
pcpu_fc_alloc(unsigned int cpu,size_t size,size_t align)127 static 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
pcpu_fc_free(void * ptr,size_t size)132 static void __init pcpu_fc_free(void *ptr, size_t size)
133 {
134 free_bootmem(__pa(ptr), size);
135 }
136
pcpu_cpu_distance(unsigned int from,unsigned int to)137 static 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
pcpup_populate_pte(unsigned long addr)149 static void __init pcpup_populate_pte(unsigned long addr)
150 {
151 populate_extra_pte(addr);
152 }
153
setup_percpu_segment(int cpu)154 static 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
setup_per_cpu_areas(void)167 void __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 }
276