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1 /*
2  * Generic VM initialization for x86-64 NUMA setups.
3  * Copyright 2002,2003 Andi Kleen, SuSE Labs.
4  */
5 #include <linux/kernel.h>
6 #include <linux/mm.h>
7 #include <linux/string.h>
8 #include <linux/init.h>
9 #include <linux/bootmem.h>
10 #include <linux/mmzone.h>
11 #include <linux/ctype.h>
12 #include <linux/module.h>
13 #include <linux/nodemask.h>
14 #include <linux/sched.h>
15 
16 #include <asm/e820.h>
17 #include <asm/proto.h>
18 #include <asm/dma.h>
19 #include <asm/numa.h>
20 #include <asm/acpi.h>
21 #include <asm/k8.h>
22 
23 struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
24 EXPORT_SYMBOL(node_data);
25 
26 struct memnode memnode;
27 
28 s16 apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
29 	[0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE
30 };
31 
32 int numa_off __initdata;
33 static unsigned long __initdata nodemap_addr;
34 static unsigned long __initdata nodemap_size;
35 
36 /*
37  * Given a shift value, try to populate memnodemap[]
38  * Returns :
39  * 1 if OK
40  * 0 if memnodmap[] too small (of shift too small)
41  * -1 if node overlap or lost ram (shift too big)
42  */
populate_memnodemap(const struct bootnode * nodes,int numnodes,int shift,int * nodeids)43 static int __init populate_memnodemap(const struct bootnode *nodes,
44 				      int numnodes, int shift, int *nodeids)
45 {
46 	unsigned long addr, end;
47 	int i, res = -1;
48 
49 	memset(memnodemap, 0xff, sizeof(s16)*memnodemapsize);
50 	for (i = 0; i < numnodes; i++) {
51 		addr = nodes[i].start;
52 		end = nodes[i].end;
53 		if (addr >= end)
54 			continue;
55 		if ((end >> shift) >= memnodemapsize)
56 			return 0;
57 		do {
58 			if (memnodemap[addr >> shift] != NUMA_NO_NODE)
59 				return -1;
60 
61 			if (!nodeids)
62 				memnodemap[addr >> shift] = i;
63 			else
64 				memnodemap[addr >> shift] = nodeids[i];
65 
66 			addr += (1UL << shift);
67 		} while (addr < end);
68 		res = 1;
69 	}
70 	return res;
71 }
72 
allocate_cachealigned_memnodemap(void)73 static int __init allocate_cachealigned_memnodemap(void)
74 {
75 	unsigned long addr;
76 
77 	memnodemap = memnode.embedded_map;
78 	if (memnodemapsize <= ARRAY_SIZE(memnode.embedded_map))
79 		return 0;
80 
81 	addr = 0x8000;
82 	nodemap_size = roundup(sizeof(s16) * memnodemapsize, L1_CACHE_BYTES);
83 	nodemap_addr = find_e820_area(addr, max_pfn<<PAGE_SHIFT,
84 				      nodemap_size, L1_CACHE_BYTES);
85 	if (nodemap_addr == -1UL) {
86 		printk(KERN_ERR
87 		       "NUMA: Unable to allocate Memory to Node hash map\n");
88 		nodemap_addr = nodemap_size = 0;
89 		return -1;
90 	}
91 	memnodemap = phys_to_virt(nodemap_addr);
92 	reserve_early(nodemap_addr, nodemap_addr + nodemap_size, "MEMNODEMAP");
93 
94 	printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
95 	       nodemap_addr, nodemap_addr + nodemap_size);
96 	return 0;
97 }
98 
99 /*
100  * The LSB of all start and end addresses in the node map is the value of the
101  * maximum possible shift.
102  */
extract_lsb_from_nodes(const struct bootnode * nodes,int numnodes)103 static int __init extract_lsb_from_nodes(const struct bootnode *nodes,
104 					 int numnodes)
105 {
106 	int i, nodes_used = 0;
107 	unsigned long start, end;
108 	unsigned long bitfield = 0, memtop = 0;
109 
110 	for (i = 0; i < numnodes; i++) {
111 		start = nodes[i].start;
112 		end = nodes[i].end;
113 		if (start >= end)
114 			continue;
115 		bitfield |= start;
116 		nodes_used++;
117 		if (end > memtop)
118 			memtop = end;
119 	}
120 	if (nodes_used <= 1)
121 		i = 63;
122 	else
123 		i = find_first_bit(&bitfield, sizeof(unsigned long)*8);
124 	memnodemapsize = (memtop >> i)+1;
125 	return i;
126 }
127 
compute_hash_shift(struct bootnode * nodes,int numnodes,int * nodeids)128 int __init compute_hash_shift(struct bootnode *nodes, int numnodes,
129 			      int *nodeids)
130 {
131 	int shift;
132 
133 	shift = extract_lsb_from_nodes(nodes, numnodes);
134 	if (allocate_cachealigned_memnodemap())
135 		return -1;
136 	printk(KERN_DEBUG "NUMA: Using %d for the hash shift.\n",
137 		shift);
138 
139 	if (populate_memnodemap(nodes, numnodes, shift, nodeids) != 1) {
140 		printk(KERN_INFO "Your memory is not aligned you need to "
141 		       "rebuild your kernel with a bigger NODEMAPSIZE "
142 		       "shift=%d\n", shift);
143 		return -1;
144 	}
145 	return shift;
146 }
147 
__early_pfn_to_nid(unsigned long pfn)148 int __meminit  __early_pfn_to_nid(unsigned long pfn)
149 {
150 	return phys_to_nid(pfn << PAGE_SHIFT);
151 }
152 
early_node_mem(int nodeid,unsigned long start,unsigned long end,unsigned long size,unsigned long align)153 static void * __init early_node_mem(int nodeid, unsigned long start,
154 				    unsigned long end, unsigned long size,
155 				    unsigned long align)
156 {
157 	unsigned long mem = find_e820_area(start, end, size, align);
158 	void *ptr;
159 
160 	if (mem != -1L)
161 		return __va(mem);
162 
163 	ptr = __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
164 	if (ptr == NULL) {
165 		printk(KERN_ERR "Cannot find %lu bytes in node %d\n",
166 		       size, nodeid);
167 		return NULL;
168 	}
169 	return ptr;
170 }
171 
172 /* Initialize bootmem allocator for a node */
setup_node_bootmem(int nodeid,unsigned long start,unsigned long end)173 void __init setup_node_bootmem(int nodeid, unsigned long start,
174 			       unsigned long end)
175 {
176 	unsigned long start_pfn, last_pfn, bootmap_pages, bootmap_size;
177 	unsigned long bootmap_start, nodedata_phys;
178 	void *bootmap;
179 	const int pgdat_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
180 	int nid;
181 
182 	start = roundup(start, ZONE_ALIGN);
183 
184 	printk(KERN_INFO "Bootmem setup node %d %016lx-%016lx\n", nodeid,
185 	       start, end);
186 
187 	start_pfn = start >> PAGE_SHIFT;
188 	last_pfn = end >> PAGE_SHIFT;
189 
190 	node_data[nodeid] = early_node_mem(nodeid, start, end, pgdat_size,
191 					   SMP_CACHE_BYTES);
192 	if (node_data[nodeid] == NULL)
193 		return;
194 	nodedata_phys = __pa(node_data[nodeid]);
195 	printk(KERN_INFO "  NODE_DATA [%016lx - %016lx]\n", nodedata_phys,
196 		nodedata_phys + pgdat_size - 1);
197 
198 	memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t));
199 	NODE_DATA(nodeid)->bdata = &bootmem_node_data[nodeid];
200 	NODE_DATA(nodeid)->node_start_pfn = start_pfn;
201 	NODE_DATA(nodeid)->node_spanned_pages = last_pfn - start_pfn;
202 
203 	/*
204 	 * Find a place for the bootmem map
205 	 * nodedata_phys could be on other nodes by alloc_bootmem,
206 	 * so need to sure bootmap_start not to be small, otherwise
207 	 * early_node_mem will get that with find_e820_area instead
208 	 * of alloc_bootmem, that could clash with reserved range
209 	 */
210 	bootmap_pages = bootmem_bootmap_pages(last_pfn - start_pfn);
211 	nid = phys_to_nid(nodedata_phys);
212 	if (nid == nodeid)
213 		bootmap_start = roundup(nodedata_phys + pgdat_size, PAGE_SIZE);
214 	else
215 		bootmap_start = roundup(start, PAGE_SIZE);
216 	/*
217 	 * SMP_CACHE_BYTES could be enough, but init_bootmem_node like
218 	 * to use that to align to PAGE_SIZE
219 	 */
220 	bootmap = early_node_mem(nodeid, bootmap_start, end,
221 				 bootmap_pages<<PAGE_SHIFT, PAGE_SIZE);
222 	if (bootmap == NULL)  {
223 		if (nodedata_phys < start || nodedata_phys >= end)
224 			free_bootmem(nodedata_phys, pgdat_size);
225 		node_data[nodeid] = NULL;
226 		return;
227 	}
228 	bootmap_start = __pa(bootmap);
229 
230 	bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
231 					 bootmap_start >> PAGE_SHIFT,
232 					 start_pfn, last_pfn);
233 
234 	printk(KERN_INFO "  bootmap [%016lx -  %016lx] pages %lx\n",
235 		 bootmap_start, bootmap_start + bootmap_size - 1,
236 		 bootmap_pages);
237 
238 	free_bootmem_with_active_regions(nodeid, end);
239 
240 	/*
241 	 * convert early reserve to bootmem reserve earlier
242 	 * otherwise early_node_mem could use early reserved mem
243 	 * on previous node
244 	 */
245 	early_res_to_bootmem(start, end);
246 
247 	/*
248 	 * in some case early_node_mem could use alloc_bootmem
249 	 * to get range on other node, don't reserve that again
250 	 */
251 	if (nid != nodeid)
252 		printk(KERN_INFO "    NODE_DATA(%d) on node %d\n", nodeid, nid);
253 	else
254 		reserve_bootmem_node(NODE_DATA(nodeid), nodedata_phys,
255 					pgdat_size, BOOTMEM_DEFAULT);
256 	nid = phys_to_nid(bootmap_start);
257 	if (nid != nodeid)
258 		printk(KERN_INFO "    bootmap(%d) on node %d\n", nodeid, nid);
259 	else
260 		reserve_bootmem_node(NODE_DATA(nodeid), bootmap_start,
261 				 bootmap_pages<<PAGE_SHIFT, BOOTMEM_DEFAULT);
262 
263 #ifdef CONFIG_ACPI_NUMA
264 	srat_reserve_add_area(nodeid);
265 #endif
266 	node_set_online(nodeid);
267 }
268 
269 /*
270  * There are unfortunately some poorly designed mainboards around that
271  * only connect memory to a single CPU. This breaks the 1:1 cpu->node
272  * mapping. To avoid this fill in the mapping for all possible CPUs,
273  * as the number of CPUs is not known yet. We round robin the existing
274  * nodes.
275  */
numa_init_array(void)276 void __init numa_init_array(void)
277 {
278 	int rr, i;
279 
280 	rr = first_node(node_online_map);
281 	for (i = 0; i < nr_cpu_ids; i++) {
282 		if (early_cpu_to_node(i) != NUMA_NO_NODE)
283 			continue;
284 		numa_set_node(i, rr);
285 		rr = next_node(rr, node_online_map);
286 		if (rr == MAX_NUMNODES)
287 			rr = first_node(node_online_map);
288 	}
289 }
290 
291 #ifdef CONFIG_NUMA_EMU
292 /* Numa emulation */
293 static char *cmdline __initdata;
294 
295 /*
296  * Setups up nid to range from addr to addr + size.  If the end
297  * boundary is greater than max_addr, then max_addr is used instead.
298  * The return value is 0 if there is additional memory left for
299  * allocation past addr and -1 otherwise.  addr is adjusted to be at
300  * the end of the node.
301  */
setup_node_range(int nid,struct bootnode * nodes,u64 * addr,u64 size,u64 max_addr)302 static int __init setup_node_range(int nid, struct bootnode *nodes, u64 *addr,
303 				   u64 size, u64 max_addr)
304 {
305 	int ret = 0;
306 
307 	nodes[nid].start = *addr;
308 	*addr += size;
309 	if (*addr >= max_addr) {
310 		*addr = max_addr;
311 		ret = -1;
312 	}
313 	nodes[nid].end = *addr;
314 	node_set(nid, node_possible_map);
315 	printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n", nid,
316 	       nodes[nid].start, nodes[nid].end,
317 	       (nodes[nid].end - nodes[nid].start) >> 20);
318 	return ret;
319 }
320 
321 /*
322  * Splits num_nodes nodes up equally starting at node_start.  The return value
323  * is the number of nodes split up and addr is adjusted to be at the end of the
324  * last node allocated.
325  */
split_nodes_equally(struct bootnode * nodes,u64 * addr,u64 max_addr,int node_start,int num_nodes)326 static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
327 				      u64 max_addr, int node_start,
328 				      int num_nodes)
329 {
330 	unsigned int big;
331 	u64 size;
332 	int i;
333 
334 	if (num_nodes <= 0)
335 		return -1;
336 	if (num_nodes > MAX_NUMNODES)
337 		num_nodes = MAX_NUMNODES;
338 	size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
339 	       num_nodes;
340 	/*
341 	 * Calculate the number of big nodes that can be allocated as a result
342 	 * of consolidating the leftovers.
343 	 */
344 	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
345 	      FAKE_NODE_MIN_SIZE;
346 
347 	/* Round down to nearest FAKE_NODE_MIN_SIZE. */
348 	size &= FAKE_NODE_MIN_HASH_MASK;
349 	if (!size) {
350 		printk(KERN_ERR "Not enough memory for each node.  "
351 		       "NUMA emulation disabled.\n");
352 		return -1;
353 	}
354 
355 	for (i = node_start; i < num_nodes + node_start; i++) {
356 		u64 end = *addr + size;
357 
358 		if (i < big)
359 			end += FAKE_NODE_MIN_SIZE;
360 		/*
361 		 * The final node can have the remaining system RAM.  Other
362 		 * nodes receive roughly the same amount of available pages.
363 		 */
364 		if (i == num_nodes + node_start - 1)
365 			end = max_addr;
366 		else
367 			while (end - *addr - e820_hole_size(*addr, end) <
368 			       size) {
369 				end += FAKE_NODE_MIN_SIZE;
370 				if (end > max_addr) {
371 					end = max_addr;
372 					break;
373 				}
374 			}
375 		if (setup_node_range(i, nodes, addr, end - *addr, max_addr) < 0)
376 			break;
377 	}
378 	return i - node_start + 1;
379 }
380 
381 /*
382  * Splits the remaining system RAM into chunks of size.  The remaining memory is
383  * always assigned to a final node and can be asymmetric.  Returns the number of
384  * nodes split.
385  */
split_nodes_by_size(struct bootnode * nodes,u64 * addr,u64 max_addr,int node_start,u64 size)386 static int __init split_nodes_by_size(struct bootnode *nodes, u64 *addr,
387 				      u64 max_addr, int node_start, u64 size)
388 {
389 	int i = node_start;
390 	size = (size << 20) & FAKE_NODE_MIN_HASH_MASK;
391 	while (!setup_node_range(i++, nodes, addr, size, max_addr))
392 		;
393 	return i - node_start;
394 }
395 
396 /*
397  * Sets up the system RAM area from start_pfn to last_pfn according to the
398  * numa=fake command-line option.
399  */
400 static struct bootnode nodes[MAX_NUMNODES] __initdata;
401 
numa_emulation(unsigned long start_pfn,unsigned long last_pfn)402 static int __init numa_emulation(unsigned long start_pfn, unsigned long last_pfn)
403 {
404 	u64 size, addr = start_pfn << PAGE_SHIFT;
405 	u64 max_addr = last_pfn << PAGE_SHIFT;
406 	int num_nodes = 0, num = 0, coeff_flag, coeff = -1, i;
407 
408 	memset(&nodes, 0, sizeof(nodes));
409 	/*
410 	 * If the numa=fake command-line is just a single number N, split the
411 	 * system RAM into N fake nodes.
412 	 */
413 	if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
414 		long n = simple_strtol(cmdline, NULL, 0);
415 
416 		num_nodes = split_nodes_equally(nodes, &addr, max_addr, 0, n);
417 		if (num_nodes < 0)
418 			return num_nodes;
419 		goto out;
420 	}
421 
422 	/* Parse the command line. */
423 	for (coeff_flag = 0; ; cmdline++) {
424 		if (*cmdline && isdigit(*cmdline)) {
425 			num = num * 10 + *cmdline - '0';
426 			continue;
427 		}
428 		if (*cmdline == '*') {
429 			if (num > 0)
430 				coeff = num;
431 			coeff_flag = 1;
432 		}
433 		if (!*cmdline || *cmdline == ',') {
434 			if (!coeff_flag)
435 				coeff = 1;
436 			/*
437 			 * Round down to the nearest FAKE_NODE_MIN_SIZE.
438 			 * Command-line coefficients are in megabytes.
439 			 */
440 			size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
441 			if (size)
442 				for (i = 0; i < coeff; i++, num_nodes++)
443 					if (setup_node_range(num_nodes, nodes,
444 						&addr, size, max_addr) < 0)
445 						goto done;
446 			if (!*cmdline)
447 				break;
448 			coeff_flag = 0;
449 			coeff = -1;
450 		}
451 		num = 0;
452 	}
453 done:
454 	if (!num_nodes)
455 		return -1;
456 	/* Fill remainder of system RAM, if appropriate. */
457 	if (addr < max_addr) {
458 		if (coeff_flag && coeff < 0) {
459 			/* Split remaining nodes into num-sized chunks */
460 			num_nodes += split_nodes_by_size(nodes, &addr, max_addr,
461 							 num_nodes, num);
462 			goto out;
463 		}
464 		switch (*(cmdline - 1)) {
465 		case '*':
466 			/* Split remaining nodes into coeff chunks */
467 			if (coeff <= 0)
468 				break;
469 			num_nodes += split_nodes_equally(nodes, &addr, max_addr,
470 							 num_nodes, coeff);
471 			break;
472 		case ',':
473 			/* Do not allocate remaining system RAM */
474 			break;
475 		default:
476 			/* Give one final node */
477 			setup_node_range(num_nodes, nodes, &addr,
478 					 max_addr - addr, max_addr);
479 			num_nodes++;
480 		}
481 	}
482 out:
483 	memnode_shift = compute_hash_shift(nodes, num_nodes, NULL);
484 	if (memnode_shift < 0) {
485 		memnode_shift = 0;
486 		printk(KERN_ERR "No NUMA hash function found.  NUMA emulation "
487 		       "disabled.\n");
488 		return -1;
489 	}
490 
491 	/*
492 	 * We need to vacate all active ranges that may have been registered by
493 	 * SRAT and set acpi_numa to -1 so that srat_disabled() always returns
494 	 * true.  NUMA emulation has succeeded so we will not scan ACPI nodes.
495 	 */
496 	remove_all_active_ranges();
497 #ifdef CONFIG_ACPI_NUMA
498 	acpi_numa = -1;
499 #endif
500 	for_each_node_mask(i, node_possible_map) {
501 		e820_register_active_regions(i, nodes[i].start >> PAGE_SHIFT,
502 						nodes[i].end >> PAGE_SHIFT);
503 		setup_node_bootmem(i, nodes[i].start, nodes[i].end);
504 	}
505 	acpi_fake_nodes(nodes, num_nodes);
506 	numa_init_array();
507 	return 0;
508 }
509 #endif /* CONFIG_NUMA_EMU */
510 
initmem_init(unsigned long start_pfn,unsigned long last_pfn)511 void __init initmem_init(unsigned long start_pfn, unsigned long last_pfn)
512 {
513 	int i;
514 
515 	nodes_clear(node_possible_map);
516 	nodes_clear(node_online_map);
517 
518 #ifdef CONFIG_NUMA_EMU
519 	if (cmdline && !numa_emulation(start_pfn, last_pfn))
520 		return;
521 	nodes_clear(node_possible_map);
522 	nodes_clear(node_online_map);
523 #endif
524 
525 #ifdef CONFIG_ACPI_NUMA
526 	if (!numa_off && !acpi_scan_nodes(start_pfn << PAGE_SHIFT,
527 					  last_pfn << PAGE_SHIFT))
528 		return;
529 	nodes_clear(node_possible_map);
530 	nodes_clear(node_online_map);
531 #endif
532 
533 #ifdef CONFIG_K8_NUMA
534 	if (!numa_off && !k8_scan_nodes(start_pfn<<PAGE_SHIFT,
535 					last_pfn<<PAGE_SHIFT))
536 		return;
537 	nodes_clear(node_possible_map);
538 	nodes_clear(node_online_map);
539 #endif
540 	printk(KERN_INFO "%s\n",
541 	       numa_off ? "NUMA turned off" : "No NUMA configuration found");
542 
543 	printk(KERN_INFO "Faking a node at %016lx-%016lx\n",
544 	       start_pfn << PAGE_SHIFT,
545 	       last_pfn << PAGE_SHIFT);
546 	/* setup dummy node covering all memory */
547 	memnode_shift = 63;
548 	memnodemap = memnode.embedded_map;
549 	memnodemap[0] = 0;
550 	node_set_online(0);
551 	node_set(0, node_possible_map);
552 	for (i = 0; i < nr_cpu_ids; i++)
553 		numa_set_node(i, 0);
554 	e820_register_active_regions(0, start_pfn, last_pfn);
555 	setup_node_bootmem(0, start_pfn << PAGE_SHIFT, last_pfn << PAGE_SHIFT);
556 }
557 
numa_free_all_bootmem(void)558 unsigned long __init numa_free_all_bootmem(void)
559 {
560 	unsigned long pages = 0;
561 	int i;
562 
563 	for_each_online_node(i)
564 		pages += free_all_bootmem_node(NODE_DATA(i));
565 
566 	return pages;
567 }
568 
paging_init(void)569 void __init paging_init(void)
570 {
571 	unsigned long max_zone_pfns[MAX_NR_ZONES];
572 
573 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
574 	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
575 	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
576 	max_zone_pfns[ZONE_NORMAL] = max_pfn;
577 
578 	sparse_memory_present_with_active_regions(MAX_NUMNODES);
579 	sparse_init();
580 
581 	free_area_init_nodes(max_zone_pfns);
582 }
583 
numa_setup(char * opt)584 static __init int numa_setup(char *opt)
585 {
586 	if (!opt)
587 		return -EINVAL;
588 	if (!strncmp(opt, "off", 3))
589 		numa_off = 1;
590 #ifdef CONFIG_NUMA_EMU
591 	if (!strncmp(opt, "fake=", 5))
592 		cmdline = opt + 5;
593 #endif
594 #ifdef CONFIG_ACPI_NUMA
595 	if (!strncmp(opt, "noacpi", 6))
596 		acpi_numa = -1;
597 	if (!strncmp(opt, "hotadd=", 7))
598 		hotadd_percent = simple_strtoul(opt+7, NULL, 10);
599 #endif
600 	return 0;
601 }
602 early_param("numa", numa_setup);
603 
604 #ifdef CONFIG_NUMA
605 /*
606  * Setup early cpu_to_node.
607  *
608  * Populate cpu_to_node[] only if x86_cpu_to_apicid[],
609  * and apicid_to_node[] tables have valid entries for a CPU.
610  * This means we skip cpu_to_node[] initialisation for NUMA
611  * emulation and faking node case (when running a kernel compiled
612  * for NUMA on a non NUMA box), which is OK as cpu_to_node[]
613  * is already initialized in a round robin manner at numa_init_array,
614  * prior to this call, and this initialization is good enough
615  * for the fake NUMA cases.
616  *
617  * Called before the per_cpu areas are setup.
618  */
init_cpu_to_node(void)619 void __init init_cpu_to_node(void)
620 {
621 	int cpu;
622 	u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid);
623 
624 	BUG_ON(cpu_to_apicid == NULL);
625 
626 	for_each_possible_cpu(cpu) {
627 		int node;
628 		u16 apicid = cpu_to_apicid[cpu];
629 
630 		if (apicid == BAD_APICID)
631 			continue;
632 		node = apicid_to_node[apicid];
633 		if (node == NUMA_NO_NODE)
634 			continue;
635 		if (!node_online(node))
636 			continue;
637 		numa_set_node(cpu, node);
638 	}
639 }
640 #endif
641 
642 
643