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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * NUMA emulation
4 */
5#include <linux/kernel.h>
6#include <linux/errno.h>
7#include <linux/topology.h>
8#include <linux/memblock.h>
9#include <linux/numa_memblks.h>
10#include <asm/numa.h>
11#include <acpi/acpi_numa.h>
12
13#define FAKE_NODE_MIN_SIZE ((u64)32 << 20)
14#define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1UL))
15
16int emu_nid_to_phys[MAX_NUMNODES];
17static char *emu_cmdline __initdata;
18
19int __init numa_emu_cmdline(char *str)
20{
21 emu_cmdline = str;
22 return 0;
23}
24
25static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
26{
27 int i;
28
29 for (i = 0; i < mi->nr_blks; i++)
30 if (mi->blk[i].nid == nid)
31 return i;
32 return -ENOENT;
33}
34
35static u64 __init mem_hole_size(u64 start, u64 end)
36{
37 unsigned long start_pfn = PFN_UP(start);
38 unsigned long end_pfn = PFN_DOWN(end);
39
40 if (start_pfn < end_pfn)
41 return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
42 return 0;
43}
44
45/*
46 * Sets up nid to range from @start to @end. The return value is -errno if
47 * something went wrong, 0 otherwise.
48 */
49static int __init emu_setup_memblk(struct numa_meminfo *ei,
50 struct numa_meminfo *pi,
51 int nid, int phys_blk, u64 size)
52{
53 struct numa_memblk *eb = &ei->blk[ei->nr_blks];
54 struct numa_memblk *pb = &pi->blk[phys_blk];
55
56 if (ei->nr_blks >= NR_NODE_MEMBLKS) {
57 pr_err("NUMA: Too many emulated memblks, failing emulation\n");
58 return -EINVAL;
59 }
60
61 ei->nr_blks++;
62 eb->start = pb->start;
63 eb->end = pb->start + size;
64 eb->nid = nid;
65
66 if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
67 emu_nid_to_phys[nid] = pb->nid;
68
69 pb->start += size;
70 if (pb->start >= pb->end) {
71 WARN_ON_ONCE(pb->start > pb->end);
72 numa_remove_memblk_from(phys_blk, pi);
73 }
74
75 printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
76 nid, eb->start, eb->end - 1, (eb->end - eb->start) / SZ_1M);
77 return 0;
78}
79
80/*
81 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
82 * to max_addr.
83 *
84 * Returns zero on success or negative on error.
85 */
86static int __init split_nodes_interleave(struct numa_meminfo *ei,
87 struct numa_meminfo *pi,
88 u64 addr, u64 max_addr, int nr_nodes)
89{
90 nodemask_t physnode_mask = numa_nodes_parsed;
91 u64 size;
92 int big;
93 int nid = 0;
94 int i, ret;
95
96 if (nr_nodes <= 0)
97 return -1;
98 if (nr_nodes > MAX_NUMNODES) {
99 pr_info("numa=fake=%d too large, reducing to %d\n",
100 nr_nodes, MAX_NUMNODES);
101 nr_nodes = MAX_NUMNODES;
102 }
103
104 /*
105 * Calculate target node size. x86_32 freaks on __udivdi3() so do
106 * the division in ulong number of pages and convert back.
107 */
108 size = max_addr - addr - mem_hole_size(addr, max_addr);
109 size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
110
111 /*
112 * Calculate the number of big nodes that can be allocated as a result
113 * of consolidating the remainder.
114 */
115 big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
116 FAKE_NODE_MIN_SIZE;
117
118 size &= FAKE_NODE_MIN_HASH_MASK;
119 if (!size) {
120 pr_err("Not enough memory for each node. "
121 "NUMA emulation disabled.\n");
122 return -1;
123 }
124
125 /*
126 * Continue to fill physical nodes with fake nodes until there is no
127 * memory left on any of them.
128 */
129 while (!nodes_empty(physnode_mask)) {
130 for_each_node_mask(i, physnode_mask) {
131 u64 dma32_end = numa_emu_dma_end();
132 u64 start, limit, end;
133 int phys_blk;
134
135 phys_blk = emu_find_memblk_by_nid(i, pi);
136 if (phys_blk < 0) {
137 node_clear(i, physnode_mask);
138 continue;
139 }
140 start = pi->blk[phys_blk].start;
141 limit = pi->blk[phys_blk].end;
142 end = start + size;
143
144 if (nid < big)
145 end += FAKE_NODE_MIN_SIZE;
146
147 /*
148 * Continue to add memory to this fake node if its
149 * non-reserved memory is less than the per-node size.
150 */
151 while (end - start - mem_hole_size(start, end) < size) {
152 end += FAKE_NODE_MIN_SIZE;
153 if (end > limit) {
154 end = limit;
155 break;
156 }
157 }
158
159 /*
160 * If there won't be at least FAKE_NODE_MIN_SIZE of
161 * non-reserved memory in ZONE_DMA32 for the next node,
162 * this one must extend to the boundary.
163 */
164 if (end < dma32_end && dma32_end - end -
165 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
166 end = dma32_end;
167
168 /*
169 * If there won't be enough non-reserved memory for the
170 * next node, this one must extend to the end of the
171 * physical node.
172 */
173 if (limit - end - mem_hole_size(end, limit) < size)
174 end = limit;
175
176 ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
177 phys_blk,
178 min(end, limit) - start);
179 if (ret < 0)
180 return ret;
181 }
182 }
183 return 0;
184}
185
186/*
187 * Returns the end address of a node so that there is at least `size' amount of
188 * non-reserved memory or `max_addr' is reached.
189 */
190static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
191{
192 u64 end = start + size;
193
194 while (end - start - mem_hole_size(start, end) < size) {
195 end += FAKE_NODE_MIN_SIZE;
196 if (end > max_addr) {
197 end = max_addr;
198 break;
199 }
200 }
201 return end;
202}
203
204static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
205{
206 unsigned long max_pfn = PHYS_PFN(max_addr);
207 unsigned long base_pfn = PHYS_PFN(base);
208 unsigned long hole_pfns = PHYS_PFN(hole);
209
210 return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
211}
212
213/*
214 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
215 * `addr' to `max_addr'.
216 *
217 * Returns node ID of the next node on success or negative error code.
218 */
219static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
220 struct numa_meminfo *pi,
221 u64 addr, u64 max_addr, u64 size,
222 int nr_nodes, struct numa_memblk *pblk,
223 int nid)
224{
225 nodemask_t physnode_mask = numa_nodes_parsed;
226 int i, ret, uniform = 0;
227 u64 min_size;
228
229 if ((!size && !nr_nodes) || (nr_nodes && !pblk))
230 return -1;
231
232 /*
233 * In the 'uniform' case split the passed in physical node by
234 * nr_nodes, in the non-uniform case, ignore the passed in
235 * physical block and try to create nodes of at least size
236 * @size.
237 *
238 * In the uniform case, split the nodes strictly by physical
239 * capacity, i.e. ignore holes. In the non-uniform case account
240 * for holes and treat @size as a minimum floor.
241 */
242 if (!nr_nodes)
243 nr_nodes = MAX_NUMNODES;
244 else {
245 nodes_clear(physnode_mask);
246 node_set(pblk->nid, physnode_mask);
247 uniform = 1;
248 }
249
250 if (uniform) {
251 min_size = uniform_size(max_addr, addr, 0, nr_nodes);
252 size = min_size;
253 } else {
254 /*
255 * The limit on emulated nodes is MAX_NUMNODES, so the
256 * size per node is increased accordingly if the
257 * requested size is too small. This creates a uniform
258 * distribution of node sizes across the entire machine
259 * (but not necessarily over physical nodes).
260 */
261 min_size = uniform_size(max_addr, addr,
262 mem_hole_size(addr, max_addr), nr_nodes);
263 }
264 min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
265 if (size < min_size) {
266 pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
267 size / SZ_1M, min_size / SZ_1M);
268 size = min_size;
269 }
270 size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);
271
272 /*
273 * Fill physical nodes with fake nodes of size until there is no memory
274 * left on any of them.
275 */
276 while (!nodes_empty(physnode_mask)) {
277 for_each_node_mask(i, physnode_mask) {
278 u64 dma32_end = numa_emu_dma_end();
279 u64 start, limit, end;
280 int phys_blk;
281
282 phys_blk = emu_find_memblk_by_nid(i, pi);
283 if (phys_blk < 0) {
284 node_clear(i, physnode_mask);
285 continue;
286 }
287
288 start = pi->blk[phys_blk].start;
289 limit = pi->blk[phys_blk].end;
290
291 if (uniform)
292 end = start + size;
293 else
294 end = find_end_of_node(start, limit, size);
295 /*
296 * If there won't be at least FAKE_NODE_MIN_SIZE of
297 * non-reserved memory in ZONE_DMA32 for the next node,
298 * this one must extend to the boundary.
299 */
300 if (end < dma32_end && dma32_end - end -
301 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
302 end = dma32_end;
303
304 /*
305 * If there won't be enough non-reserved memory for the
306 * next node, this one must extend to the end of the
307 * physical node.
308 */
309 if ((limit - end - mem_hole_size(end, limit) < size)
310 && !uniform)
311 end = limit;
312
313 ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
314 phys_blk,
315 min(end, limit) - start);
316 if (ret < 0)
317 return ret;
318 }
319 }
320 return nid;
321}
322
323static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
324 struct numa_meminfo *pi,
325 u64 addr, u64 max_addr, u64 size)
326{
327 return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
328 0, NULL, 0);
329}
330
331static int __init setup_emu2phys_nid(int *dfl_phys_nid)
332{
333 int i, max_emu_nid = 0;
334
335 *dfl_phys_nid = NUMA_NO_NODE;
336 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
337 if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
338 max_emu_nid = i;
339 if (*dfl_phys_nid == NUMA_NO_NODE)
340 *dfl_phys_nid = emu_nid_to_phys[i];
341 }
342 }
343
344 return max_emu_nid;
345}
346
347/**
348 * numa_emulation - Emulate NUMA nodes
349 * @numa_meminfo: NUMA configuration to massage
350 * @numa_dist_cnt: The size of the physical NUMA distance table
351 *
352 * Emulate NUMA nodes according to the numa=fake kernel parameter.
353 * @numa_meminfo contains the physical memory configuration and is modified
354 * to reflect the emulated configuration on success. @numa_dist_cnt is
355 * used to determine the size of the physical distance table.
356 *
357 * On success, the following modifications are made.
358 *
359 * - @numa_meminfo is updated to reflect the emulated nodes.
360 *
361 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
362 * emulated nodes.
363 *
364 * - NUMA distance table is rebuilt to represent distances between emulated
365 * nodes. The distances are determined considering how emulated nodes
366 * are mapped to physical nodes and match the actual distances.
367 *
368 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
369 * nodes. This is used by numa_add_cpu() and numa_remove_cpu().
370 *
371 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
372 * identity mapping and no other modification is made.
373 */
374void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
375{
376 static struct numa_meminfo ei __initdata;
377 static struct numa_meminfo pi __initdata;
378 const u64 max_addr = PFN_PHYS(max_pfn);
379 u8 *phys_dist = NULL;
380 size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
381 int max_emu_nid, dfl_phys_nid;
382 int i, j, ret;
383 nodemask_t physnode_mask = numa_nodes_parsed;
384
385 if (!emu_cmdline)
386 goto no_emu;
387
388 memset(&ei, 0, sizeof(ei));
389 pi = *numa_meminfo;
390
391 for (i = 0; i < MAX_NUMNODES; i++)
392 emu_nid_to_phys[i] = NUMA_NO_NODE;
393
394 /*
395 * If the numa=fake command-line contains a 'M' or 'G', it represents
396 * the fixed node size. Otherwise, if it is just a single number N,
397 * split the system RAM into N fake nodes.
398 */
399 if (strchr(emu_cmdline, 'U')) {
400 unsigned long n;
401 int nid = 0, nr_created;
402
403 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
404 ret = -1;
405 for_each_node_mask(i, physnode_mask) {
406 /*
407 * The reason we pass in blk[0] is due to
408 * numa_remove_memblk_from() called by
409 * emu_setup_memblk() will delete entry 0
410 * and then move everything else up in the pi.blk
411 * array. Therefore we should always be looking
412 * at blk[0].
413 */
414 ret = split_nodes_size_interleave_uniform(&ei, &pi,
415 pi.blk[0].start, pi.blk[0].end, 0,
416 n, &pi.blk[0], nid);
417 if (ret < 0)
418 break;
419
420 /*
421 * If no memory was found for this physical node,
422 * skip the under-allocation check.
423 */
424 if (ret == nid)
425 continue;
426
427 nr_created = ret - nid;
428 if (nr_created < n) {
429 pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
430 __func__, i, nr_created, n);
431 ret = -1;
432 break;
433 }
434 nid = ret;
435 }
436 } else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
437 u64 size;
438
439 size = memparse(emu_cmdline, &emu_cmdline);
440 ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
441 } else {
442 unsigned long n;
443
444 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
445 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
446 }
447 if (*emu_cmdline == ':')
448 emu_cmdline++;
449
450 if (ret < 0)
451 goto no_emu;
452
453 if (numa_cleanup_meminfo(&ei) < 0) {
454 pr_warn("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
455 goto no_emu;
456 }
457
458 /* copy the physical distance table */
459 if (numa_dist_cnt) {
460 phys_dist = memblock_alloc(phys_size, PAGE_SIZE);
461 if (!phys_dist) {
462 pr_warn("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
463 goto no_emu;
464 }
465
466 for (i = 0; i < numa_dist_cnt; i++)
467 for (j = 0; j < numa_dist_cnt; j++)
468 phys_dist[i * numa_dist_cnt + j] =
469 node_distance(i, j);
470 }
471
472 /*
473 * Determine the max emulated nid and the default phys nid to use
474 * for unmapped nodes.
475 */
476 max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
477
478 /* Make sure numa_nodes_parsed only contains emulated nodes */
479 nodes_clear(numa_nodes_parsed);
480 for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
481 if (ei.blk[i].start != ei.blk[i].end &&
482 ei.blk[i].nid != NUMA_NO_NODE)
483 node_set(ei.blk[i].nid, numa_nodes_parsed);
484
485 /* fix pxm_to_node_map[] and node_to_pxm_map[] to avoid collision
486 * with faked numa nodes, particularly during later memory hotplug
487 * handling, and also update numa_nodes_parsed accordingly.
488 */
489 ret = fix_pxm_node_maps(max_emu_nid);
490 if (ret < 0)
491 goto no_emu;
492
493 /* commit */
494 *numa_meminfo = ei;
495
496 numa_emu_update_cpu_to_node(emu_nid_to_phys, max_emu_nid + 1);
497
498 /* make sure all emulated nodes are mapped to a physical node */
499 for (i = 0; i < max_emu_nid + 1; i++)
500 if (emu_nid_to_phys[i] == NUMA_NO_NODE)
501 emu_nid_to_phys[i] = dfl_phys_nid;
502
503 /* transform distance table */
504 numa_reset_distance();
505 for (i = 0; i < max_emu_nid + 1; i++) {
506 for (j = 0; j < max_emu_nid + 1; j++) {
507 int physi = emu_nid_to_phys[i];
508 int physj = emu_nid_to_phys[j];
509 int dist;
510
511 if (get_option(&emu_cmdline, &dist) == 2)
512 ;
513 else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
514 dist = physi == physj ?
515 LOCAL_DISTANCE : REMOTE_DISTANCE;
516 else
517 dist = phys_dist[physi * numa_dist_cnt + physj];
518
519 numa_set_distance(i, j, dist);
520 }
521 }
522 for (i = 0; i < numa_distance_cnt; i++) {
523 for (j = 0; j < numa_distance_cnt; j++) {
524 int physi, physj;
525 u8 dist;
526
527 /* distance between fake nodes is already ok */
528 if (emu_nid_to_phys[i] != NUMA_NO_NODE &&
529 emu_nid_to_phys[j] != NUMA_NO_NODE)
530 continue;
531 if (emu_nid_to_phys[i] != NUMA_NO_NODE)
532 physi = emu_nid_to_phys[i];
533 else
534 physi = i - max_emu_nid;
535 if (emu_nid_to_phys[j] != NUMA_NO_NODE)
536 physj = emu_nid_to_phys[j];
537 else
538 physj = j - max_emu_nid;
539 dist = phys_dist[physi * numa_dist_cnt + physj];
540 numa_set_distance(i, j, dist);
541 }
542 }
543
544 /* free the copied physical distance table */
545 memblock_free(phys_dist, phys_size);
546 return;
547
548no_emu:
549 numa_nodes_parsed = physnode_mask;
550 /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
551 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
552 emu_nid_to_phys[i] = i;
553}
554
555#ifndef CONFIG_DEBUG_PER_CPU_MAPS
556void numa_add_cpu(unsigned int cpu)
557{
558 int physnid, nid;
559
560 nid = early_cpu_to_node(cpu);
561 BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
562
563 physnid = emu_nid_to_phys[nid];
564
565 /*
566 * Map the cpu to each emulated node that is allocated on the physical
567 * node of the cpu's apic id.
568 */
569 for_each_online_node(nid)
570 if (emu_nid_to_phys[nid] == physnid)
571 cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
572}
573
574void numa_remove_cpu(unsigned int cpu)
575{
576 int i;
577
578 for_each_online_node(i)
579 cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
580}
581#else /* !CONFIG_DEBUG_PER_CPU_MAPS */
582static void numa_set_cpumask(unsigned int cpu, bool enable)
583{
584 int nid, physnid;
585
586 nid = early_cpu_to_node(cpu);
587 if (nid == NUMA_NO_NODE) {
588 /* early_cpu_to_node() already emits a warning and trace */
589 return;
590 }
591
592 physnid = emu_nid_to_phys[nid];
593
594 for_each_online_node(nid) {
595 if (emu_nid_to_phys[nid] != physnid)
596 continue;
597
598 debug_cpumask_set_cpu(cpu, nid, enable);
599 }
600}
601
602void numa_add_cpu(unsigned int cpu)
603{
604 numa_set_cpumask(cpu, true);
605}
606
607void numa_remove_cpu(unsigned int cpu)
608{
609 numa_set_cpumask(cpu, false);
610}
611#endif /* !CONFIG_DEBUG_PER_CPU_MAPS */