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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 <asm/dma.h>
10
11#include "numa_internal.h"
12
13static int emu_nid_to_phys[MAX_NUMNODES];
14static char *emu_cmdline __initdata;
15
16void __init numa_emu_cmdline(char *str)
17{
18 emu_cmdline = str;
19}
20
21static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
22{
23 int i;
24
25 for (i = 0; i < mi->nr_blks; i++)
26 if (mi->blk[i].nid == nid)
27 return i;
28 return -ENOENT;
29}
30
31static u64 __init mem_hole_size(u64 start, u64 end)
32{
33 unsigned long start_pfn = PFN_UP(start);
34 unsigned long end_pfn = PFN_DOWN(end);
35
36 if (start_pfn < end_pfn)
37 return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
38 return 0;
39}
40
41/*
42 * Sets up nid to range from @start to @end. The return value is -errno if
43 * something went wrong, 0 otherwise.
44 */
45static int __init emu_setup_memblk(struct numa_meminfo *ei,
46 struct numa_meminfo *pi,
47 int nid, int phys_blk, u64 size)
48{
49 struct numa_memblk *eb = &ei->blk[ei->nr_blks];
50 struct numa_memblk *pb = &pi->blk[phys_blk];
51
52 if (ei->nr_blks >= NR_NODE_MEMBLKS) {
53 pr_err("NUMA: Too many emulated memblks, failing emulation\n");
54 return -EINVAL;
55 }
56
57 ei->nr_blks++;
58 eb->start = pb->start;
59 eb->end = pb->start + size;
60 eb->nid = nid;
61
62 if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
63 emu_nid_to_phys[nid] = pb->nid;
64
65 pb->start += size;
66 if (pb->start >= pb->end) {
67 WARN_ON_ONCE(pb->start > pb->end);
68 numa_remove_memblk_from(phys_blk, pi);
69 }
70
71 printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
72 nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
73 return 0;
74}
75
76/*
77 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
78 * to max_addr.
79 *
80 * Returns zero on success or negative on error.
81 */
82static int __init split_nodes_interleave(struct numa_meminfo *ei,
83 struct numa_meminfo *pi,
84 u64 addr, u64 max_addr, int nr_nodes)
85{
86 nodemask_t physnode_mask = numa_nodes_parsed;
87 u64 size;
88 int big;
89 int nid = 0;
90 int i, ret;
91
92 if (nr_nodes <= 0)
93 return -1;
94 if (nr_nodes > MAX_NUMNODES) {
95 pr_info("numa=fake=%d too large, reducing to %d\n",
96 nr_nodes, MAX_NUMNODES);
97 nr_nodes = MAX_NUMNODES;
98 }
99
100 /*
101 * Calculate target node size. x86_32 freaks on __udivdi3() so do
102 * the division in ulong number of pages and convert back.
103 */
104 size = max_addr - addr - mem_hole_size(addr, max_addr);
105 size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
106
107 /*
108 * Calculate the number of big nodes that can be allocated as a result
109 * of consolidating the remainder.
110 */
111 big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
112 FAKE_NODE_MIN_SIZE;
113
114 size &= FAKE_NODE_MIN_HASH_MASK;
115 if (!size) {
116 pr_err("Not enough memory for each node. "
117 "NUMA emulation disabled.\n");
118 return -1;
119 }
120
121 /*
122 * Continue to fill physical nodes with fake nodes until there is no
123 * memory left on any of them.
124 */
125 while (nodes_weight(physnode_mask)) {
126 for_each_node_mask(i, physnode_mask) {
127 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
128 u64 start, limit, end;
129 int phys_blk;
130
131 phys_blk = emu_find_memblk_by_nid(i, pi);
132 if (phys_blk < 0) {
133 node_clear(i, physnode_mask);
134 continue;
135 }
136 start = pi->blk[phys_blk].start;
137 limit = pi->blk[phys_blk].end;
138 end = start + size;
139
140 if (nid < big)
141 end += FAKE_NODE_MIN_SIZE;
142
143 /*
144 * Continue to add memory to this fake node if its
145 * non-reserved memory is less than the per-node size.
146 */
147 while (end - start - mem_hole_size(start, end) < size) {
148 end += FAKE_NODE_MIN_SIZE;
149 if (end > limit) {
150 end = limit;
151 break;
152 }
153 }
154
155 /*
156 * If there won't be at least FAKE_NODE_MIN_SIZE of
157 * non-reserved memory in ZONE_DMA32 for the next node,
158 * this one must extend to the boundary.
159 */
160 if (end < dma32_end && dma32_end - end -
161 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
162 end = dma32_end;
163
164 /*
165 * If there won't be enough non-reserved memory for the
166 * next node, this one must extend to the end of the
167 * physical node.
168 */
169 if (limit - end - mem_hole_size(end, limit) < size)
170 end = limit;
171
172 ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
173 phys_blk,
174 min(end, limit) - start);
175 if (ret < 0)
176 return ret;
177 }
178 }
179 return 0;
180}
181
182/*
183 * Returns the end address of a node so that there is at least `size' amount of
184 * non-reserved memory or `max_addr' is reached.
185 */
186static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
187{
188 u64 end = start + size;
189
190 while (end - start - mem_hole_size(start, end) < size) {
191 end += FAKE_NODE_MIN_SIZE;
192 if (end > max_addr) {
193 end = max_addr;
194 break;
195 }
196 }
197 return end;
198}
199
200static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
201{
202 unsigned long max_pfn = PHYS_PFN(max_addr);
203 unsigned long base_pfn = PHYS_PFN(base);
204 unsigned long hole_pfns = PHYS_PFN(hole);
205
206 return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
207}
208
209/*
210 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
211 * `addr' to `max_addr'.
212 *
213 * Returns zero on success or negative on error.
214 */
215static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
216 struct numa_meminfo *pi,
217 u64 addr, u64 max_addr, u64 size,
218 int nr_nodes, struct numa_memblk *pblk,
219 int nid)
220{
221 nodemask_t physnode_mask = numa_nodes_parsed;
222 int i, ret, uniform = 0;
223 u64 min_size;
224
225 if ((!size && !nr_nodes) || (nr_nodes && !pblk))
226 return -1;
227
228 /*
229 * In the 'uniform' case split the passed in physical node by
230 * nr_nodes, in the non-uniform case, ignore the passed in
231 * physical block and try to create nodes of at least size
232 * @size.
233 *
234 * In the uniform case, split the nodes strictly by physical
235 * capacity, i.e. ignore holes. In the non-uniform case account
236 * for holes and treat @size as a minimum floor.
237 */
238 if (!nr_nodes)
239 nr_nodes = MAX_NUMNODES;
240 else {
241 nodes_clear(physnode_mask);
242 node_set(pblk->nid, physnode_mask);
243 uniform = 1;
244 }
245
246 if (uniform) {
247 min_size = uniform_size(max_addr, addr, 0, nr_nodes);
248 size = min_size;
249 } else {
250 /*
251 * The limit on emulated nodes is MAX_NUMNODES, so the
252 * size per node is increased accordingly if the
253 * requested size is too small. This creates a uniform
254 * distribution of node sizes across the entire machine
255 * (but not necessarily over physical nodes).
256 */
257 min_size = uniform_size(max_addr, addr,
258 mem_hole_size(addr, max_addr), nr_nodes);
259 }
260 min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
261 if (size < min_size) {
262 pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
263 size >> 20, min_size >> 20);
264 size = min_size;
265 }
266 size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);
267
268 /*
269 * Fill physical nodes with fake nodes of size until there is no memory
270 * left on any of them.
271 */
272 while (nodes_weight(physnode_mask)) {
273 for_each_node_mask(i, physnode_mask) {
274 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
275 u64 start, limit, end;
276 int phys_blk;
277
278 phys_blk = emu_find_memblk_by_nid(i, pi);
279 if (phys_blk < 0) {
280 node_clear(i, physnode_mask);
281 continue;
282 }
283
284 start = pi->blk[phys_blk].start;
285 limit = pi->blk[phys_blk].end;
286
287 if (uniform)
288 end = start + size;
289 else
290 end = find_end_of_node(start, limit, size);
291 /*
292 * If there won't be at least FAKE_NODE_MIN_SIZE of
293 * non-reserved memory in ZONE_DMA32 for the next node,
294 * this one must extend to the boundary.
295 */
296 if (end < dma32_end && dma32_end - end -
297 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
298 end = dma32_end;
299
300 /*
301 * If there won't be enough non-reserved memory for the
302 * next node, this one must extend to the end of the
303 * physical node.
304 */
305 if ((limit - end - mem_hole_size(end, limit) < size)
306 && !uniform)
307 end = limit;
308
309 ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
310 phys_blk,
311 min(end, limit) - start);
312 if (ret < 0)
313 return ret;
314 }
315 }
316 return nid;
317}
318
319static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
320 struct numa_meminfo *pi,
321 u64 addr, u64 max_addr, u64 size)
322{
323 return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
324 0, NULL, 0);
325}
326
327static int __init setup_emu2phys_nid(int *dfl_phys_nid)
328{
329 int i, max_emu_nid = 0;
330
331 *dfl_phys_nid = NUMA_NO_NODE;
332 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
333 if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
334 max_emu_nid = i;
335 if (*dfl_phys_nid == NUMA_NO_NODE)
336 *dfl_phys_nid = emu_nid_to_phys[i];
337 }
338 }
339
340 return max_emu_nid;
341}
342
343/**
344 * numa_emulation - Emulate NUMA nodes
345 * @numa_meminfo: NUMA configuration to massage
346 * @numa_dist_cnt: The size of the physical NUMA distance table
347 *
348 * Emulate NUMA nodes according to the numa=fake kernel parameter.
349 * @numa_meminfo contains the physical memory configuration and is modified
350 * to reflect the emulated configuration on success. @numa_dist_cnt is
351 * used to determine the size of the physical distance table.
352 *
353 * On success, the following modifications are made.
354 *
355 * - @numa_meminfo is updated to reflect the emulated nodes.
356 *
357 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
358 * emulated nodes.
359 *
360 * - NUMA distance table is rebuilt to represent distances between emulated
361 * nodes. The distances are determined considering how emulated nodes
362 * are mapped to physical nodes and match the actual distances.
363 *
364 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
365 * nodes. This is used by numa_add_cpu() and numa_remove_cpu().
366 *
367 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
368 * identity mapping and no other modification is made.
369 */
370void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
371{
372 static struct numa_meminfo ei __initdata;
373 static struct numa_meminfo pi __initdata;
374 const u64 max_addr = PFN_PHYS(max_pfn);
375 u8 *phys_dist = NULL;
376 size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
377 int max_emu_nid, dfl_phys_nid;
378 int i, j, ret;
379
380 if (!emu_cmdline)
381 goto no_emu;
382
383 memset(&ei, 0, sizeof(ei));
384 pi = *numa_meminfo;
385
386 for (i = 0; i < MAX_NUMNODES; i++)
387 emu_nid_to_phys[i] = NUMA_NO_NODE;
388
389 /*
390 * If the numa=fake command-line contains a 'M' or 'G', it represents
391 * the fixed node size. Otherwise, if it is just a single number N,
392 * split the system RAM into N fake nodes.
393 */
394 if (strchr(emu_cmdline, 'U')) {
395 nodemask_t physnode_mask = numa_nodes_parsed;
396 unsigned long n;
397 int nid = 0;
398
399 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
400 ret = -1;
401 for_each_node_mask(i, physnode_mask) {
402 /*
403 * The reason we pass in blk[0] is due to
404 * numa_remove_memblk_from() called by
405 * emu_setup_memblk() will delete entry 0
406 * and then move everything else up in the pi.blk
407 * array. Therefore we should always be looking
408 * at blk[0].
409 */
410 ret = split_nodes_size_interleave_uniform(&ei, &pi,
411 pi.blk[0].start, pi.blk[0].end, 0,
412 n, &pi.blk[0], nid);
413 if (ret < 0)
414 break;
415 if (ret < n) {
416 pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
417 __func__, i, ret, n);
418 ret = -1;
419 break;
420 }
421 nid = ret;
422 }
423 } else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
424 u64 size;
425
426 size = memparse(emu_cmdline, &emu_cmdline);
427 ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
428 } else {
429 unsigned long n;
430
431 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
432 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
433 }
434 if (*emu_cmdline == ':')
435 emu_cmdline++;
436
437 if (ret < 0)
438 goto no_emu;
439
440 if (numa_cleanup_meminfo(&ei) < 0) {
441 pr_warn("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
442 goto no_emu;
443 }
444
445 /* copy the physical distance table */
446 if (numa_dist_cnt) {
447 u64 phys;
448
449 phys = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
450 phys_size, PAGE_SIZE);
451 if (!phys) {
452 pr_warn("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
453 goto no_emu;
454 }
455 memblock_reserve(phys, phys_size);
456 phys_dist = __va(phys);
457
458 for (i = 0; i < numa_dist_cnt; i++)
459 for (j = 0; j < numa_dist_cnt; j++)
460 phys_dist[i * numa_dist_cnt + j] =
461 node_distance(i, j);
462 }
463
464 /*
465 * Determine the max emulated nid and the default phys nid to use
466 * for unmapped nodes.
467 */
468 max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
469
470 /* commit */
471 *numa_meminfo = ei;
472
473 /* Make sure numa_nodes_parsed only contains emulated nodes */
474 nodes_clear(numa_nodes_parsed);
475 for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
476 if (ei.blk[i].start != ei.blk[i].end &&
477 ei.blk[i].nid != NUMA_NO_NODE)
478 node_set(ei.blk[i].nid, numa_nodes_parsed);
479
480 /*
481 * Transform __apicid_to_node table to use emulated nids by
482 * reverse-mapping phys_nid. The maps should always exist but fall
483 * back to zero just in case.
484 */
485 for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
486 if (__apicid_to_node[i] == NUMA_NO_NODE)
487 continue;
488 for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
489 if (__apicid_to_node[i] == emu_nid_to_phys[j])
490 break;
491 __apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
492 }
493
494 /* make sure all emulated nodes are mapped to a physical node */
495 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
496 if (emu_nid_to_phys[i] == NUMA_NO_NODE)
497 emu_nid_to_phys[i] = dfl_phys_nid;
498
499 /* transform distance table */
500 numa_reset_distance();
501 for (i = 0; i < max_emu_nid + 1; i++) {
502 for (j = 0; j < max_emu_nid + 1; j++) {
503 int physi = emu_nid_to_phys[i];
504 int physj = emu_nid_to_phys[j];
505 int dist;
506
507 if (get_option(&emu_cmdline, &dist) == 2)
508 ;
509 else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
510 dist = physi == physj ?
511 LOCAL_DISTANCE : REMOTE_DISTANCE;
512 else
513 dist = phys_dist[physi * numa_dist_cnt + physj];
514
515 numa_set_distance(i, j, dist);
516 }
517 }
518
519 /* free the copied physical distance table */
520 if (phys_dist)
521 memblock_free(__pa(phys_dist), phys_size);
522 return;
523
524no_emu:
525 /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
526 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
527 emu_nid_to_phys[i] = i;
528}
529
530#ifndef CONFIG_DEBUG_PER_CPU_MAPS
531void numa_add_cpu(int cpu)
532{
533 int physnid, nid;
534
535 nid = early_cpu_to_node(cpu);
536 BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
537
538 physnid = emu_nid_to_phys[nid];
539
540 /*
541 * Map the cpu to each emulated node that is allocated on the physical
542 * node of the cpu's apic id.
543 */
544 for_each_online_node(nid)
545 if (emu_nid_to_phys[nid] == physnid)
546 cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
547}
548
549void numa_remove_cpu(int cpu)
550{
551 int i;
552
553 for_each_online_node(i)
554 cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
555}
556#else /* !CONFIG_DEBUG_PER_CPU_MAPS */
557static void numa_set_cpumask(int cpu, bool enable)
558{
559 int nid, physnid;
560
561 nid = early_cpu_to_node(cpu);
562 if (nid == NUMA_NO_NODE) {
563 /* early_cpu_to_node() already emits a warning and trace */
564 return;
565 }
566
567 physnid = emu_nid_to_phys[nid];
568
569 for_each_online_node(nid) {
570 if (emu_nid_to_phys[nid] != physnid)
571 continue;
572
573 debug_cpumask_set_cpu(cpu, nid, enable);
574 }
575}
576
577void numa_add_cpu(int cpu)
578{
579 numa_set_cpumask(cpu, true);
580}
581
582void numa_remove_cpu(int cpu)
583{
584 numa_set_cpumask(cpu, false);
585}
586#endif /* !CONFIG_DEBUG_PER_CPU_MAPS */
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/bootmem.h>
10#include <asm/dma.h>
11
12#include "numa_internal.h"
13
14static int emu_nid_to_phys[MAX_NUMNODES];
15static char *emu_cmdline __initdata;
16
17void __init numa_emu_cmdline(char *str)
18{
19 emu_cmdline = str;
20}
21
22static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
23{
24 int i;
25
26 for (i = 0; i < mi->nr_blks; i++)
27 if (mi->blk[i].nid == nid)
28 return i;
29 return -ENOENT;
30}
31
32static u64 __init mem_hole_size(u64 start, u64 end)
33{
34 unsigned long start_pfn = PFN_UP(start);
35 unsigned long end_pfn = PFN_DOWN(end);
36
37 if (start_pfn < end_pfn)
38 return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
39 return 0;
40}
41
42/*
43 * Sets up nid to range from @start to @end. The return value is -errno if
44 * something went wrong, 0 otherwise.
45 */
46static int __init emu_setup_memblk(struct numa_meminfo *ei,
47 struct numa_meminfo *pi,
48 int nid, int phys_blk, u64 size)
49{
50 struct numa_memblk *eb = &ei->blk[ei->nr_blks];
51 struct numa_memblk *pb = &pi->blk[phys_blk];
52
53 if (ei->nr_blks >= NR_NODE_MEMBLKS) {
54 pr_err("NUMA: Too many emulated memblks, failing emulation\n");
55 return -EINVAL;
56 }
57
58 ei->nr_blks++;
59 eb->start = pb->start;
60 eb->end = pb->start + size;
61 eb->nid = nid;
62
63 if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
64 emu_nid_to_phys[nid] = nid;
65
66 pb->start += size;
67 if (pb->start >= pb->end) {
68 WARN_ON_ONCE(pb->start > pb->end);
69 numa_remove_memblk_from(phys_blk, pi);
70 }
71
72 printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
73 nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
74 return 0;
75}
76
77/*
78 * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
79 * to max_addr.
80 *
81 * Returns zero on success or negative on error.
82 */
83static int __init split_nodes_interleave(struct numa_meminfo *ei,
84 struct numa_meminfo *pi,
85 u64 addr, u64 max_addr, int nr_nodes)
86{
87 nodemask_t physnode_mask = numa_nodes_parsed;
88 u64 size;
89 int big;
90 int nid = 0;
91 int i, ret;
92
93 if (nr_nodes <= 0)
94 return -1;
95 if (nr_nodes > MAX_NUMNODES) {
96 pr_info("numa=fake=%d too large, reducing to %d\n",
97 nr_nodes, MAX_NUMNODES);
98 nr_nodes = MAX_NUMNODES;
99 }
100
101 /*
102 * Calculate target node size. x86_32 freaks on __udivdi3() so do
103 * the division in ulong number of pages and convert back.
104 */
105 size = max_addr - addr - mem_hole_size(addr, max_addr);
106 size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
107
108 /*
109 * Calculate the number of big nodes that can be allocated as a result
110 * of consolidating the remainder.
111 */
112 big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
113 FAKE_NODE_MIN_SIZE;
114
115 size &= FAKE_NODE_MIN_HASH_MASK;
116 if (!size) {
117 pr_err("Not enough memory for each node. "
118 "NUMA emulation disabled.\n");
119 return -1;
120 }
121
122 /*
123 * Continue to fill physical nodes with fake nodes until there is no
124 * memory left on any of them.
125 */
126 while (nodes_weight(physnode_mask)) {
127 for_each_node_mask(i, physnode_mask) {
128 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
129 u64 start, limit, end;
130 int phys_blk;
131
132 phys_blk = emu_find_memblk_by_nid(i, pi);
133 if (phys_blk < 0) {
134 node_clear(i, physnode_mask);
135 continue;
136 }
137 start = pi->blk[phys_blk].start;
138 limit = pi->blk[phys_blk].end;
139 end = start + size;
140
141 if (nid < big)
142 end += FAKE_NODE_MIN_SIZE;
143
144 /*
145 * Continue to add memory to this fake node if its
146 * non-reserved memory is less than the per-node size.
147 */
148 while (end - start - mem_hole_size(start, end) < size) {
149 end += FAKE_NODE_MIN_SIZE;
150 if (end > limit) {
151 end = limit;
152 break;
153 }
154 }
155
156 /*
157 * If there won't be at least FAKE_NODE_MIN_SIZE of
158 * non-reserved memory in ZONE_DMA32 for the next node,
159 * this one must extend to the boundary.
160 */
161 if (end < dma32_end && dma32_end - end -
162 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
163 end = dma32_end;
164
165 /*
166 * If there won't be enough non-reserved memory for the
167 * next node, this one must extend to the end of the
168 * physical node.
169 */
170 if (limit - end - mem_hole_size(end, limit) < size)
171 end = limit;
172
173 ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
174 phys_blk,
175 min(end, limit) - start);
176 if (ret < 0)
177 return ret;
178 }
179 }
180 return 0;
181}
182
183/*
184 * Returns the end address of a node so that there is at least `size' amount of
185 * non-reserved memory or `max_addr' is reached.
186 */
187static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
188{
189 u64 end = start + size;
190
191 while (end - start - mem_hole_size(start, end) < size) {
192 end += FAKE_NODE_MIN_SIZE;
193 if (end > max_addr) {
194 end = max_addr;
195 break;
196 }
197 }
198 return end;
199}
200
201/*
202 * Sets up fake nodes of `size' interleaved over physical nodes ranging from
203 * `addr' to `max_addr'.
204 *
205 * Returns zero on success or negative on error.
206 */
207static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
208 struct numa_meminfo *pi,
209 u64 addr, u64 max_addr, u64 size)
210{
211 nodemask_t physnode_mask = numa_nodes_parsed;
212 u64 min_size;
213 int nid = 0;
214 int i, ret;
215
216 if (!size)
217 return -1;
218 /*
219 * The limit on emulated nodes is MAX_NUMNODES, so the size per node is
220 * increased accordingly if the requested size is too small. This
221 * creates a uniform distribution of node sizes across the entire
222 * machine (but not necessarily over physical nodes).
223 */
224 min_size = (max_addr - addr - mem_hole_size(addr, max_addr)) / MAX_NUMNODES;
225 min_size = max(min_size, FAKE_NODE_MIN_SIZE);
226 if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
227 min_size = (min_size + FAKE_NODE_MIN_SIZE) &
228 FAKE_NODE_MIN_HASH_MASK;
229 if (size < min_size) {
230 pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
231 size >> 20, min_size >> 20);
232 size = min_size;
233 }
234 size &= FAKE_NODE_MIN_HASH_MASK;
235
236 /*
237 * Fill physical nodes with fake nodes of size until there is no memory
238 * left on any of them.
239 */
240 while (nodes_weight(physnode_mask)) {
241 for_each_node_mask(i, physnode_mask) {
242 u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
243 u64 start, limit, end;
244 int phys_blk;
245
246 phys_blk = emu_find_memblk_by_nid(i, pi);
247 if (phys_blk < 0) {
248 node_clear(i, physnode_mask);
249 continue;
250 }
251 start = pi->blk[phys_blk].start;
252 limit = pi->blk[phys_blk].end;
253
254 end = find_end_of_node(start, limit, size);
255 /*
256 * If there won't be at least FAKE_NODE_MIN_SIZE of
257 * non-reserved memory in ZONE_DMA32 for the next node,
258 * this one must extend to the boundary.
259 */
260 if (end < dma32_end && dma32_end - end -
261 mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
262 end = dma32_end;
263
264 /*
265 * If there won't be enough non-reserved memory for the
266 * next node, this one must extend to the end of the
267 * physical node.
268 */
269 if (limit - end - mem_hole_size(end, limit) < size)
270 end = limit;
271
272 ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
273 phys_blk,
274 min(end, limit) - start);
275 if (ret < 0)
276 return ret;
277 }
278 }
279 return 0;
280}
281
282int __init setup_emu2phys_nid(int *dfl_phys_nid)
283{
284 int i, max_emu_nid = 0;
285
286 *dfl_phys_nid = NUMA_NO_NODE;
287 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
288 if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
289 max_emu_nid = i;
290 if (*dfl_phys_nid == NUMA_NO_NODE)
291 *dfl_phys_nid = emu_nid_to_phys[i];
292 }
293 }
294
295 return max_emu_nid;
296}
297
298/**
299 * numa_emulation - Emulate NUMA nodes
300 * @numa_meminfo: NUMA configuration to massage
301 * @numa_dist_cnt: The size of the physical NUMA distance table
302 *
303 * Emulate NUMA nodes according to the numa=fake kernel parameter.
304 * @numa_meminfo contains the physical memory configuration and is modified
305 * to reflect the emulated configuration on success. @numa_dist_cnt is
306 * used to determine the size of the physical distance table.
307 *
308 * On success, the following modifications are made.
309 *
310 * - @numa_meminfo is updated to reflect the emulated nodes.
311 *
312 * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
313 * emulated nodes.
314 *
315 * - NUMA distance table is rebuilt to represent distances between emulated
316 * nodes. The distances are determined considering how emulated nodes
317 * are mapped to physical nodes and match the actual distances.
318 *
319 * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
320 * nodes. This is used by numa_add_cpu() and numa_remove_cpu().
321 *
322 * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
323 * identity mapping and no other modification is made.
324 */
325void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
326{
327 static struct numa_meminfo ei __initdata;
328 static struct numa_meminfo pi __initdata;
329 const u64 max_addr = PFN_PHYS(max_pfn);
330 u8 *phys_dist = NULL;
331 size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
332 int max_emu_nid, dfl_phys_nid;
333 int i, j, ret;
334
335 if (!emu_cmdline)
336 goto no_emu;
337
338 memset(&ei, 0, sizeof(ei));
339 pi = *numa_meminfo;
340
341 for (i = 0; i < MAX_NUMNODES; i++)
342 emu_nid_to_phys[i] = NUMA_NO_NODE;
343
344 /*
345 * If the numa=fake command-line contains a 'M' or 'G', it represents
346 * the fixed node size. Otherwise, if it is just a single number N,
347 * split the system RAM into N fake nodes.
348 */
349 if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
350 u64 size;
351
352 size = memparse(emu_cmdline, &emu_cmdline);
353 ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
354 } else {
355 unsigned long n;
356
357 n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
358 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
359 }
360 if (*emu_cmdline == ':')
361 emu_cmdline++;
362
363 if (ret < 0)
364 goto no_emu;
365
366 if (numa_cleanup_meminfo(&ei) < 0) {
367 pr_warning("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
368 goto no_emu;
369 }
370
371 /* copy the physical distance table */
372 if (numa_dist_cnt) {
373 u64 phys;
374
375 phys = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
376 phys_size, PAGE_SIZE);
377 if (!phys) {
378 pr_warning("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
379 goto no_emu;
380 }
381 memblock_reserve(phys, phys_size);
382 phys_dist = __va(phys);
383
384 for (i = 0; i < numa_dist_cnt; i++)
385 for (j = 0; j < numa_dist_cnt; j++)
386 phys_dist[i * numa_dist_cnt + j] =
387 node_distance(i, j);
388 }
389
390 /*
391 * Determine the max emulated nid and the default phys nid to use
392 * for unmapped nodes.
393 */
394 max_emu_nid = setup_emu2phys_nid(&dfl_phys_nid);
395
396 /* commit */
397 *numa_meminfo = ei;
398
399 /* Make sure numa_nodes_parsed only contains emulated nodes */
400 nodes_clear(numa_nodes_parsed);
401 for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
402 if (ei.blk[i].start != ei.blk[i].end &&
403 ei.blk[i].nid != NUMA_NO_NODE)
404 node_set(ei.blk[i].nid, numa_nodes_parsed);
405
406 /*
407 * Transform __apicid_to_node table to use emulated nids by
408 * reverse-mapping phys_nid. The maps should always exist but fall
409 * back to zero just in case.
410 */
411 for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
412 if (__apicid_to_node[i] == NUMA_NO_NODE)
413 continue;
414 for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
415 if (__apicid_to_node[i] == emu_nid_to_phys[j])
416 break;
417 __apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
418 }
419
420 /* make sure all emulated nodes are mapped to a physical node */
421 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
422 if (emu_nid_to_phys[i] == NUMA_NO_NODE)
423 emu_nid_to_phys[i] = dfl_phys_nid;
424
425 /* transform distance table */
426 numa_reset_distance();
427 for (i = 0; i < max_emu_nid + 1; i++) {
428 for (j = 0; j < max_emu_nid + 1; j++) {
429 int physi = emu_nid_to_phys[i];
430 int physj = emu_nid_to_phys[j];
431 int dist;
432
433 if (get_option(&emu_cmdline, &dist) == 2)
434 ;
435 else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
436 dist = physi == physj ?
437 LOCAL_DISTANCE : REMOTE_DISTANCE;
438 else
439 dist = phys_dist[physi * numa_dist_cnt + physj];
440
441 numa_set_distance(i, j, dist);
442 }
443 }
444
445 /* free the copied physical distance table */
446 if (phys_dist)
447 memblock_free(__pa(phys_dist), phys_size);
448 return;
449
450no_emu:
451 /* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
452 for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
453 emu_nid_to_phys[i] = i;
454}
455
456#ifndef CONFIG_DEBUG_PER_CPU_MAPS
457void numa_add_cpu(int cpu)
458{
459 int physnid, nid;
460
461 nid = early_cpu_to_node(cpu);
462 BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
463
464 physnid = emu_nid_to_phys[nid];
465
466 /*
467 * Map the cpu to each emulated node that is allocated on the physical
468 * node of the cpu's apic id.
469 */
470 for_each_online_node(nid)
471 if (emu_nid_to_phys[nid] == physnid)
472 cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
473}
474
475void numa_remove_cpu(int cpu)
476{
477 int i;
478
479 for_each_online_node(i)
480 cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
481}
482#else /* !CONFIG_DEBUG_PER_CPU_MAPS */
483static void numa_set_cpumask(int cpu, bool enable)
484{
485 int nid, physnid;
486
487 nid = early_cpu_to_node(cpu);
488 if (nid == NUMA_NO_NODE) {
489 /* early_cpu_to_node() already emits a warning and trace */
490 return;
491 }
492
493 physnid = emu_nid_to_phys[nid];
494
495 for_each_online_node(nid) {
496 if (emu_nid_to_phys[nid] != physnid)
497 continue;
498
499 debug_cpumask_set_cpu(cpu, nid, enable);
500 }
501}
502
503void numa_add_cpu(int cpu)
504{
505 numa_set_cpumask(cpu, true);
506}
507
508void numa_remove_cpu(int cpu)
509{
510 numa_set_cpumask(cpu, false);
511}
512#endif /* !CONFIG_DEBUG_PER_CPU_MAPS */