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1// SPDX-License-Identifier: GPL-2.0
2/* arch/sparc64/mm/tsb.c
3 *
4 * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
5 */
6
7#include <linux/kernel.h>
8#include <linux/preempt.h>
9#include <linux/slab.h>
10#include <linux/mm_types.h>
11#include <linux/pgtable.h>
12
13#include <asm/page.h>
14#include <asm/mmu_context.h>
15#include <asm/setup.h>
16#include <asm/tsb.h>
17#include <asm/tlb.h>
18#include <asm/oplib.h>
19
20extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
21
22static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
23{
24 vaddr >>= hash_shift;
25 return vaddr & (nentries - 1);
26}
27
28static inline int tag_compare(unsigned long tag, unsigned long vaddr)
29{
30 return (tag == (vaddr >> 22));
31}
32
33static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end)
34{
35 unsigned long idx;
36
37 for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) {
38 struct tsb *ent = &swapper_tsb[idx];
39 unsigned long match = idx << 13;
40
41 match |= (ent->tag << 22);
42 if (match >= start && match < end)
43 ent->tag = (1UL << TSB_TAG_INVALID_BIT);
44 }
45}
46
47/* TSB flushes need only occur on the processor initiating the address
48 * space modification, not on each cpu the address space has run on.
49 * Only the TLB flush needs that treatment.
50 */
51
52void flush_tsb_kernel_range(unsigned long start, unsigned long end)
53{
54 unsigned long v;
55
56 if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES)
57 return flush_tsb_kernel_range_scan(start, end);
58
59 for (v = start; v < end; v += PAGE_SIZE) {
60 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
61 KERNEL_TSB_NENTRIES);
62 struct tsb *ent = &swapper_tsb[hash];
63
64 if (tag_compare(ent->tag, v))
65 ent->tag = (1UL << TSB_TAG_INVALID_BIT);
66 }
67}
68
69static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
70 unsigned long hash_shift,
71 unsigned long nentries)
72{
73 unsigned long tag, ent, hash;
74
75 v &= ~0x1UL;
76 hash = tsb_hash(v, hash_shift, nentries);
77 ent = tsb + (hash * sizeof(struct tsb));
78 tag = (v >> 22UL);
79
80 tsb_flush(ent, tag);
81}
82
83static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
84 unsigned long tsb, unsigned long nentries)
85{
86 unsigned long i;
87
88 for (i = 0; i < tb->tlb_nr; i++)
89 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
90}
91
92#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
93static void __flush_huge_tsb_one_entry(unsigned long tsb, unsigned long v,
94 unsigned long hash_shift,
95 unsigned long nentries,
96 unsigned int hugepage_shift)
97{
98 unsigned int hpage_entries;
99 unsigned int i;
100
101 hpage_entries = 1 << (hugepage_shift - hash_shift);
102 for (i = 0; i < hpage_entries; i++)
103 __flush_tsb_one_entry(tsb, v + (i << hash_shift), hash_shift,
104 nentries);
105}
106
107static void __flush_huge_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
108 unsigned long tsb, unsigned long nentries,
109 unsigned int hugepage_shift)
110{
111 unsigned long i;
112
113 for (i = 0; i < tb->tlb_nr; i++)
114 __flush_huge_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift,
115 nentries, hugepage_shift);
116}
117#endif
118
119void flush_tsb_user(struct tlb_batch *tb)
120{
121 struct mm_struct *mm = tb->mm;
122 unsigned long nentries, base, flags;
123
124 spin_lock_irqsave(&mm->context.lock, flags);
125
126 if (tb->hugepage_shift < REAL_HPAGE_SHIFT) {
127 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
128 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
129 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
130 base = __pa(base);
131 if (tb->hugepage_shift == PAGE_SHIFT)
132 __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
133#if defined(CONFIG_HUGETLB_PAGE)
134 else
135 __flush_huge_tsb_one(tb, PAGE_SHIFT, base, nentries,
136 tb->hugepage_shift);
137#endif
138 }
139#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
140 else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
141 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
142 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
143 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
144 base = __pa(base);
145 __flush_huge_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries,
146 tb->hugepage_shift);
147 }
148#endif
149 spin_unlock_irqrestore(&mm->context.lock, flags);
150}
151
152void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr,
153 unsigned int hugepage_shift)
154{
155 unsigned long nentries, base, flags;
156
157 spin_lock_irqsave(&mm->context.lock, flags);
158
159 if (hugepage_shift < REAL_HPAGE_SHIFT) {
160 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
161 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
162 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
163 base = __pa(base);
164 if (hugepage_shift == PAGE_SHIFT)
165 __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT,
166 nentries);
167#if defined(CONFIG_HUGETLB_PAGE)
168 else
169 __flush_huge_tsb_one_entry(base, vaddr, PAGE_SHIFT,
170 nentries, hugepage_shift);
171#endif
172 }
173#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
174 else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
175 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
176 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
177 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
178 base = __pa(base);
179 __flush_huge_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT,
180 nentries, hugepage_shift);
181 }
182#endif
183 spin_unlock_irqrestore(&mm->context.lock, flags);
184}
185
186#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
187#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
188
189#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
190#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
191#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
192#endif
193
194static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
195{
196 unsigned long tsb_reg, base, tsb_paddr;
197 unsigned long page_sz, tte;
198
199 mm->context.tsb_block[tsb_idx].tsb_nentries =
200 tsb_bytes / sizeof(struct tsb);
201
202 switch (tsb_idx) {
203 case MM_TSB_BASE:
204 base = TSBMAP_8K_BASE;
205 break;
206#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
207 case MM_TSB_HUGE:
208 base = TSBMAP_4M_BASE;
209 break;
210#endif
211 default:
212 BUG();
213 }
214
215 tte = pgprot_val(PAGE_KERNEL_LOCKED);
216 tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
217 BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
218
219 /* Use the smallest page size that can map the whole TSB
220 * in one TLB entry.
221 */
222 switch (tsb_bytes) {
223 case 8192 << 0:
224 tsb_reg = 0x0UL;
225#ifdef DCACHE_ALIASING_POSSIBLE
226 base += (tsb_paddr & 8192);
227#endif
228 page_sz = 8192;
229 break;
230
231 case 8192 << 1:
232 tsb_reg = 0x1UL;
233 page_sz = 64 * 1024;
234 break;
235
236 case 8192 << 2:
237 tsb_reg = 0x2UL;
238 page_sz = 64 * 1024;
239 break;
240
241 case 8192 << 3:
242 tsb_reg = 0x3UL;
243 page_sz = 64 * 1024;
244 break;
245
246 case 8192 << 4:
247 tsb_reg = 0x4UL;
248 page_sz = 512 * 1024;
249 break;
250
251 case 8192 << 5:
252 tsb_reg = 0x5UL;
253 page_sz = 512 * 1024;
254 break;
255
256 case 8192 << 6:
257 tsb_reg = 0x6UL;
258 page_sz = 512 * 1024;
259 break;
260
261 case 8192 << 7:
262 tsb_reg = 0x7UL;
263 page_sz = 4 * 1024 * 1024;
264 break;
265
266 default:
267 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
268 current->comm, current->pid, tsb_bytes);
269 BUG();
270 }
271 tte |= pte_sz_bits(page_sz);
272
273 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
274 /* Physical mapping, no locked TLB entry for TSB. */
275 tsb_reg |= tsb_paddr;
276
277 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
278 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
279 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
280 } else {
281 tsb_reg |= base;
282 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
283 tte |= (tsb_paddr & ~(page_sz - 1UL));
284
285 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
286 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
287 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
288 }
289
290 /* Setup the Hypervisor TSB descriptor. */
291 if (tlb_type == hypervisor) {
292 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
293
294 switch (tsb_idx) {
295 case MM_TSB_BASE:
296 hp->pgsz_idx = HV_PGSZ_IDX_BASE;
297 break;
298#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
299 case MM_TSB_HUGE:
300 hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
301 break;
302#endif
303 default:
304 BUG();
305 }
306 hp->assoc = 1;
307 hp->num_ttes = tsb_bytes / 16;
308 hp->ctx_idx = 0;
309 switch (tsb_idx) {
310 case MM_TSB_BASE:
311 hp->pgsz_mask = HV_PGSZ_MASK_BASE;
312 break;
313#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
314 case MM_TSB_HUGE:
315 hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
316 break;
317#endif
318 default:
319 BUG();
320 }
321 hp->tsb_base = tsb_paddr;
322 hp->resv = 0;
323 }
324}
325
326struct kmem_cache *pgtable_cache __read_mostly;
327
328static struct kmem_cache *tsb_caches[8] __read_mostly;
329
330static const char *tsb_cache_names[8] = {
331 "tsb_8KB",
332 "tsb_16KB",
333 "tsb_32KB",
334 "tsb_64KB",
335 "tsb_128KB",
336 "tsb_256KB",
337 "tsb_512KB",
338 "tsb_1MB",
339};
340
341void __init pgtable_cache_init(void)
342{
343 unsigned long i;
344
345 pgtable_cache = kmem_cache_create("pgtable_cache",
346 PAGE_SIZE, PAGE_SIZE,
347 0,
348 _clear_page);
349 if (!pgtable_cache) {
350 prom_printf("pgtable_cache_init(): Could not create!\n");
351 prom_halt();
352 }
353
354 for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
355 unsigned long size = 8192 << i;
356 const char *name = tsb_cache_names[i];
357
358 tsb_caches[i] = kmem_cache_create(name,
359 size, size,
360 0, NULL);
361 if (!tsb_caches[i]) {
362 prom_printf("Could not create %s cache\n", name);
363 prom_halt();
364 }
365 }
366}
367
368int sysctl_tsb_ratio = -2;
369
370static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
371{
372 unsigned long num_ents = (new_size / sizeof(struct tsb));
373
374 if (sysctl_tsb_ratio < 0)
375 return num_ents - (num_ents >> -sysctl_tsb_ratio);
376 else
377 return num_ents + (num_ents >> sysctl_tsb_ratio);
378}
379
380/* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
381 * do_sparc64_fault() invokes this routine to try and grow it.
382 *
383 * When we reach the maximum TSB size supported, we stick ~0UL into
384 * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
385 * will not trigger any longer.
386 *
387 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
388 * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
389 * must be 512K aligned. It also must be physically contiguous, so we
390 * cannot use vmalloc().
391 *
392 * The idea here is to grow the TSB when the RSS of the process approaches
393 * the number of entries that the current TSB can hold at once. Currently,
394 * we trigger when the RSS hits 3/4 of the TSB capacity.
395 */
396void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
397{
398 unsigned long max_tsb_size = 1 * 1024 * 1024;
399 unsigned long new_size, old_size, flags;
400 struct tsb *old_tsb, *new_tsb;
401 unsigned long new_cache_index, old_cache_index;
402 unsigned long new_rss_limit;
403 gfp_t gfp_flags;
404
405 if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
406 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
407
408 new_cache_index = 0;
409 for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
410 new_rss_limit = tsb_size_to_rss_limit(new_size);
411 if (new_rss_limit > rss)
412 break;
413 new_cache_index++;
414 }
415
416 if (new_size == max_tsb_size)
417 new_rss_limit = ~0UL;
418
419retry_tsb_alloc:
420 gfp_flags = GFP_KERNEL;
421 if (new_size > (PAGE_SIZE * 2))
422 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
423
424 new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
425 gfp_flags, numa_node_id());
426 if (unlikely(!new_tsb)) {
427 /* Not being able to fork due to a high-order TSB
428 * allocation failure is very bad behavior. Just back
429 * down to a 0-order allocation and force no TSB
430 * growing for this address space.
431 */
432 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
433 new_cache_index > 0) {
434 new_cache_index = 0;
435 new_size = 8192;
436 new_rss_limit = ~0UL;
437 goto retry_tsb_alloc;
438 }
439
440 /* If we failed on a TSB grow, we are under serious
441 * memory pressure so don't try to grow any more.
442 */
443 if (mm->context.tsb_block[tsb_index].tsb != NULL)
444 mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
445 return;
446 }
447
448 /* Mark all tags as invalid. */
449 tsb_init(new_tsb, new_size);
450
451 /* Ok, we are about to commit the changes. If we are
452 * growing an existing TSB the locking is very tricky,
453 * so WATCH OUT!
454 *
455 * We have to hold mm->context.lock while committing to the
456 * new TSB, this synchronizes us with processors in
457 * flush_tsb_user() and switch_mm() for this address space.
458 *
459 * But even with that lock held, processors run asynchronously
460 * accessing the old TSB via TLB miss handling. This is OK
461 * because those actions are just propagating state from the
462 * Linux page tables into the TSB, page table mappings are not
463 * being changed. If a real fault occurs, the processor will
464 * synchronize with us when it hits flush_tsb_user(), this is
465 * also true for the case where vmscan is modifying the page
466 * tables. The only thing we need to be careful with is to
467 * skip any locked TSB entries during copy_tsb().
468 *
469 * When we finish committing to the new TSB, we have to drop
470 * the lock and ask all other cpus running this address space
471 * to run tsb_context_switch() to see the new TSB table.
472 */
473 spin_lock_irqsave(&mm->context.lock, flags);
474
475 old_tsb = mm->context.tsb_block[tsb_index].tsb;
476 old_cache_index =
477 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
478 old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
479 sizeof(struct tsb));
480
481
482 /* Handle multiple threads trying to grow the TSB at the same time.
483 * One will get in here first, and bump the size and the RSS limit.
484 * The others will get in here next and hit this check.
485 */
486 if (unlikely(old_tsb &&
487 (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
488 spin_unlock_irqrestore(&mm->context.lock, flags);
489
490 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
491 return;
492 }
493
494 mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
495
496 if (old_tsb) {
497 extern void copy_tsb(unsigned long old_tsb_base,
498 unsigned long old_tsb_size,
499 unsigned long new_tsb_base,
500 unsigned long new_tsb_size,
501 unsigned long page_size_shift);
502 unsigned long old_tsb_base = (unsigned long) old_tsb;
503 unsigned long new_tsb_base = (unsigned long) new_tsb;
504
505 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
506 old_tsb_base = __pa(old_tsb_base);
507 new_tsb_base = __pa(new_tsb_base);
508 }
509 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size,
510 tsb_index == MM_TSB_BASE ?
511 PAGE_SHIFT : REAL_HPAGE_SHIFT);
512 }
513
514 mm->context.tsb_block[tsb_index].tsb = new_tsb;
515 setup_tsb_params(mm, tsb_index, new_size);
516
517 spin_unlock_irqrestore(&mm->context.lock, flags);
518
519 /* If old_tsb is NULL, we're being invoked for the first time
520 * from init_new_context().
521 */
522 if (old_tsb) {
523 /* Reload it on the local cpu. */
524 tsb_context_switch(mm);
525
526 /* Now force other processors to do the same. */
527 preempt_disable();
528 smp_tsb_sync(mm);
529 preempt_enable();
530
531 /* Now it is safe to free the old tsb. */
532 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
533 }
534}
535
536int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
537{
538 unsigned long mm_rss = get_mm_rss(mm);
539#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
540 unsigned long saved_hugetlb_pte_count;
541 unsigned long saved_thp_pte_count;
542#endif
543 unsigned int i;
544
545 spin_lock_init(&mm->context.lock);
546
547 mm->context.sparc64_ctx_val = 0UL;
548
549 mm->context.tag_store = NULL;
550 spin_lock_init(&mm->context.tag_lock);
551
552#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
553 /* We reset them to zero because the fork() page copying
554 * will re-increment the counters as the parent PTEs are
555 * copied into the child address space.
556 */
557 saved_hugetlb_pte_count = mm->context.hugetlb_pte_count;
558 saved_thp_pte_count = mm->context.thp_pte_count;
559 mm->context.hugetlb_pte_count = 0;
560 mm->context.thp_pte_count = 0;
561
562 mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
563#endif
564
565 /* copy_mm() copies over the parent's mm_struct before calling
566 * us, so we need to zero out the TSB pointer or else tsb_grow()
567 * will be confused and think there is an older TSB to free up.
568 */
569 for (i = 0; i < MM_NUM_TSBS; i++)
570 mm->context.tsb_block[i].tsb = NULL;
571
572 /* If this is fork, inherit the parent's TSB size. We would
573 * grow it to that size on the first page fault anyways.
574 */
575 tsb_grow(mm, MM_TSB_BASE, mm_rss);
576
577#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
578 if (unlikely(saved_hugetlb_pte_count + saved_thp_pte_count))
579 tsb_grow(mm, MM_TSB_HUGE,
580 (saved_hugetlb_pte_count + saved_thp_pte_count) *
581 REAL_HPAGE_PER_HPAGE);
582#endif
583
584 if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
585 return -ENOMEM;
586
587 return 0;
588}
589
590static void tsb_destroy_one(struct tsb_config *tp)
591{
592 unsigned long cache_index;
593
594 if (!tp->tsb)
595 return;
596 cache_index = tp->tsb_reg_val & 0x7UL;
597 kmem_cache_free(tsb_caches[cache_index], tp->tsb);
598 tp->tsb = NULL;
599 tp->tsb_reg_val = 0UL;
600}
601
602void destroy_context(struct mm_struct *mm)
603{
604 unsigned long flags, i;
605
606 for (i = 0; i < MM_NUM_TSBS; i++)
607 tsb_destroy_one(&mm->context.tsb_block[i]);
608
609 spin_lock_irqsave(&ctx_alloc_lock, flags);
610
611 if (CTX_VALID(mm->context)) {
612 unsigned long nr = CTX_NRBITS(mm->context);
613 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
614 }
615
616 spin_unlock_irqrestore(&ctx_alloc_lock, flags);
617
618 /* If ADI tag storage was allocated for this task, free it */
619 if (mm->context.tag_store) {
620 tag_storage_desc_t *tag_desc;
621 unsigned long max_desc;
622 unsigned char *tags;
623
624 tag_desc = mm->context.tag_store;
625 max_desc = PAGE_SIZE/sizeof(tag_storage_desc_t);
626 for (i = 0; i < max_desc; i++) {
627 tags = tag_desc->tags;
628 tag_desc->tags = NULL;
629 kfree(tags);
630 tag_desc++;
631 }
632 kfree(mm->context.tag_store);
633 mm->context.tag_store = NULL;
634 }
635}
1/* arch/sparc64/mm/tsb.c
2 *
3 * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
4 */
5
6#include <linux/kernel.h>
7#include <linux/preempt.h>
8#include <linux/slab.h>
9#include <asm/page.h>
10#include <asm/tlbflush.h>
11#include <asm/tlb.h>
12#include <asm/mmu_context.h>
13#include <asm/pgtable.h>
14#include <asm/tsb.h>
15#include <asm/oplib.h>
16
17extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
18
19static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
20{
21 vaddr >>= hash_shift;
22 return vaddr & (nentries - 1);
23}
24
25static inline int tag_compare(unsigned long tag, unsigned long vaddr)
26{
27 return (tag == (vaddr >> 22));
28}
29
30/* TSB flushes need only occur on the processor initiating the address
31 * space modification, not on each cpu the address space has run on.
32 * Only the TLB flush needs that treatment.
33 */
34
35void flush_tsb_kernel_range(unsigned long start, unsigned long end)
36{
37 unsigned long v;
38
39 for (v = start; v < end; v += PAGE_SIZE) {
40 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
41 KERNEL_TSB_NENTRIES);
42 struct tsb *ent = &swapper_tsb[hash];
43
44 if (tag_compare(ent->tag, v))
45 ent->tag = (1UL << TSB_TAG_INVALID_BIT);
46 }
47}
48
49static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
50 unsigned long tsb, unsigned long nentries)
51{
52 unsigned long i;
53
54 for (i = 0; i < tb->tlb_nr; i++) {
55 unsigned long v = tb->vaddrs[i];
56 unsigned long tag, ent, hash;
57
58 v &= ~0x1UL;
59
60 hash = tsb_hash(v, hash_shift, nentries);
61 ent = tsb + (hash * sizeof(struct tsb));
62 tag = (v >> 22UL);
63
64 tsb_flush(ent, tag);
65 }
66}
67
68void flush_tsb_user(struct tlb_batch *tb)
69{
70 struct mm_struct *mm = tb->mm;
71 unsigned long nentries, base, flags;
72
73 spin_lock_irqsave(&mm->context.lock, flags);
74
75 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
76 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
77 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
78 base = __pa(base);
79 __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
80
81#ifdef CONFIG_HUGETLB_PAGE
82 if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
83 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
84 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
85 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
86 base = __pa(base);
87 __flush_tsb_one(tb, HPAGE_SHIFT, base, nentries);
88 }
89#endif
90 spin_unlock_irqrestore(&mm->context.lock, flags);
91}
92
93#if defined(CONFIG_SPARC64_PAGE_SIZE_8KB)
94#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
95#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
96#elif defined(CONFIG_SPARC64_PAGE_SIZE_64KB)
97#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_64K
98#define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_64K
99#else
100#error Broken base page size setting...
101#endif
102
103#ifdef CONFIG_HUGETLB_PAGE
104#if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
105#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_64K
106#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_64K
107#elif defined(CONFIG_HUGETLB_PAGE_SIZE_512K)
108#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_512K
109#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_512K
110#elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
111#define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
112#define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
113#else
114#error Broken huge page size setting...
115#endif
116#endif
117
118static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
119{
120 unsigned long tsb_reg, base, tsb_paddr;
121 unsigned long page_sz, tte;
122
123 mm->context.tsb_block[tsb_idx].tsb_nentries =
124 tsb_bytes / sizeof(struct tsb);
125
126 base = TSBMAP_BASE;
127 tte = pgprot_val(PAGE_KERNEL_LOCKED);
128 tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
129 BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
130
131 /* Use the smallest page size that can map the whole TSB
132 * in one TLB entry.
133 */
134 switch (tsb_bytes) {
135 case 8192 << 0:
136 tsb_reg = 0x0UL;
137#ifdef DCACHE_ALIASING_POSSIBLE
138 base += (tsb_paddr & 8192);
139#endif
140 page_sz = 8192;
141 break;
142
143 case 8192 << 1:
144 tsb_reg = 0x1UL;
145 page_sz = 64 * 1024;
146 break;
147
148 case 8192 << 2:
149 tsb_reg = 0x2UL;
150 page_sz = 64 * 1024;
151 break;
152
153 case 8192 << 3:
154 tsb_reg = 0x3UL;
155 page_sz = 64 * 1024;
156 break;
157
158 case 8192 << 4:
159 tsb_reg = 0x4UL;
160 page_sz = 512 * 1024;
161 break;
162
163 case 8192 << 5:
164 tsb_reg = 0x5UL;
165 page_sz = 512 * 1024;
166 break;
167
168 case 8192 << 6:
169 tsb_reg = 0x6UL;
170 page_sz = 512 * 1024;
171 break;
172
173 case 8192 << 7:
174 tsb_reg = 0x7UL;
175 page_sz = 4 * 1024 * 1024;
176 break;
177
178 default:
179 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
180 current->comm, current->pid, tsb_bytes);
181 do_exit(SIGSEGV);
182 }
183 tte |= pte_sz_bits(page_sz);
184
185 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
186 /* Physical mapping, no locked TLB entry for TSB. */
187 tsb_reg |= tsb_paddr;
188
189 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
190 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
191 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
192 } else {
193 tsb_reg |= base;
194 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
195 tte |= (tsb_paddr & ~(page_sz - 1UL));
196
197 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
198 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
199 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
200 }
201
202 /* Setup the Hypervisor TSB descriptor. */
203 if (tlb_type == hypervisor) {
204 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
205
206 switch (tsb_idx) {
207 case MM_TSB_BASE:
208 hp->pgsz_idx = HV_PGSZ_IDX_BASE;
209 break;
210#ifdef CONFIG_HUGETLB_PAGE
211 case MM_TSB_HUGE:
212 hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
213 break;
214#endif
215 default:
216 BUG();
217 }
218 hp->assoc = 1;
219 hp->num_ttes = tsb_bytes / 16;
220 hp->ctx_idx = 0;
221 switch (tsb_idx) {
222 case MM_TSB_BASE:
223 hp->pgsz_mask = HV_PGSZ_MASK_BASE;
224 break;
225#ifdef CONFIG_HUGETLB_PAGE
226 case MM_TSB_HUGE:
227 hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
228 break;
229#endif
230 default:
231 BUG();
232 }
233 hp->tsb_base = tsb_paddr;
234 hp->resv = 0;
235 }
236}
237
238struct kmem_cache *pgtable_cache __read_mostly;
239
240static struct kmem_cache *tsb_caches[8] __read_mostly;
241
242static const char *tsb_cache_names[8] = {
243 "tsb_8KB",
244 "tsb_16KB",
245 "tsb_32KB",
246 "tsb_64KB",
247 "tsb_128KB",
248 "tsb_256KB",
249 "tsb_512KB",
250 "tsb_1MB",
251};
252
253void __init pgtable_cache_init(void)
254{
255 unsigned long i;
256
257 pgtable_cache = kmem_cache_create("pgtable_cache",
258 PAGE_SIZE, PAGE_SIZE,
259 0,
260 _clear_page);
261 if (!pgtable_cache) {
262 prom_printf("pgtable_cache_init(): Could not create!\n");
263 prom_halt();
264 }
265
266 for (i = 0; i < 8; i++) {
267 unsigned long size = 8192 << i;
268 const char *name = tsb_cache_names[i];
269
270 tsb_caches[i] = kmem_cache_create(name,
271 size, size,
272 0, NULL);
273 if (!tsb_caches[i]) {
274 prom_printf("Could not create %s cache\n", name);
275 prom_halt();
276 }
277 }
278}
279
280int sysctl_tsb_ratio = -2;
281
282static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
283{
284 unsigned long num_ents = (new_size / sizeof(struct tsb));
285
286 if (sysctl_tsb_ratio < 0)
287 return num_ents - (num_ents >> -sysctl_tsb_ratio);
288 else
289 return num_ents + (num_ents >> sysctl_tsb_ratio);
290}
291
292/* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
293 * do_sparc64_fault() invokes this routine to try and grow it.
294 *
295 * When we reach the maximum TSB size supported, we stick ~0UL into
296 * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
297 * will not trigger any longer.
298 *
299 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
300 * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
301 * must be 512K aligned. It also must be physically contiguous, so we
302 * cannot use vmalloc().
303 *
304 * The idea here is to grow the TSB when the RSS of the process approaches
305 * the number of entries that the current TSB can hold at once. Currently,
306 * we trigger when the RSS hits 3/4 of the TSB capacity.
307 */
308void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
309{
310 unsigned long max_tsb_size = 1 * 1024 * 1024;
311 unsigned long new_size, old_size, flags;
312 struct tsb *old_tsb, *new_tsb;
313 unsigned long new_cache_index, old_cache_index;
314 unsigned long new_rss_limit;
315 gfp_t gfp_flags;
316
317 if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
318 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
319
320 new_cache_index = 0;
321 for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
322 new_rss_limit = tsb_size_to_rss_limit(new_size);
323 if (new_rss_limit > rss)
324 break;
325 new_cache_index++;
326 }
327
328 if (new_size == max_tsb_size)
329 new_rss_limit = ~0UL;
330
331retry_tsb_alloc:
332 gfp_flags = GFP_KERNEL;
333 if (new_size > (PAGE_SIZE * 2))
334 gfp_flags = __GFP_NOWARN | __GFP_NORETRY;
335
336 new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
337 gfp_flags, numa_node_id());
338 if (unlikely(!new_tsb)) {
339 /* Not being able to fork due to a high-order TSB
340 * allocation failure is very bad behavior. Just back
341 * down to a 0-order allocation and force no TSB
342 * growing for this address space.
343 */
344 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
345 new_cache_index > 0) {
346 new_cache_index = 0;
347 new_size = 8192;
348 new_rss_limit = ~0UL;
349 goto retry_tsb_alloc;
350 }
351
352 /* If we failed on a TSB grow, we are under serious
353 * memory pressure so don't try to grow any more.
354 */
355 if (mm->context.tsb_block[tsb_index].tsb != NULL)
356 mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
357 return;
358 }
359
360 /* Mark all tags as invalid. */
361 tsb_init(new_tsb, new_size);
362
363 /* Ok, we are about to commit the changes. If we are
364 * growing an existing TSB the locking is very tricky,
365 * so WATCH OUT!
366 *
367 * We have to hold mm->context.lock while committing to the
368 * new TSB, this synchronizes us with processors in
369 * flush_tsb_user() and switch_mm() for this address space.
370 *
371 * But even with that lock held, processors run asynchronously
372 * accessing the old TSB via TLB miss handling. This is OK
373 * because those actions are just propagating state from the
374 * Linux page tables into the TSB, page table mappings are not
375 * being changed. If a real fault occurs, the processor will
376 * synchronize with us when it hits flush_tsb_user(), this is
377 * also true for the case where vmscan is modifying the page
378 * tables. The only thing we need to be careful with is to
379 * skip any locked TSB entries during copy_tsb().
380 *
381 * When we finish committing to the new TSB, we have to drop
382 * the lock and ask all other cpus running this address space
383 * to run tsb_context_switch() to see the new TSB table.
384 */
385 spin_lock_irqsave(&mm->context.lock, flags);
386
387 old_tsb = mm->context.tsb_block[tsb_index].tsb;
388 old_cache_index =
389 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
390 old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
391 sizeof(struct tsb));
392
393
394 /* Handle multiple threads trying to grow the TSB at the same time.
395 * One will get in here first, and bump the size and the RSS limit.
396 * The others will get in here next and hit this check.
397 */
398 if (unlikely(old_tsb &&
399 (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
400 spin_unlock_irqrestore(&mm->context.lock, flags);
401
402 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
403 return;
404 }
405
406 mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
407
408 if (old_tsb) {
409 extern void copy_tsb(unsigned long old_tsb_base,
410 unsigned long old_tsb_size,
411 unsigned long new_tsb_base,
412 unsigned long new_tsb_size);
413 unsigned long old_tsb_base = (unsigned long) old_tsb;
414 unsigned long new_tsb_base = (unsigned long) new_tsb;
415
416 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
417 old_tsb_base = __pa(old_tsb_base);
418 new_tsb_base = __pa(new_tsb_base);
419 }
420 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
421 }
422
423 mm->context.tsb_block[tsb_index].tsb = new_tsb;
424 setup_tsb_params(mm, tsb_index, new_size);
425
426 spin_unlock_irqrestore(&mm->context.lock, flags);
427
428 /* If old_tsb is NULL, we're being invoked for the first time
429 * from init_new_context().
430 */
431 if (old_tsb) {
432 /* Reload it on the local cpu. */
433 tsb_context_switch(mm);
434
435 /* Now force other processors to do the same. */
436 preempt_disable();
437 smp_tsb_sync(mm);
438 preempt_enable();
439
440 /* Now it is safe to free the old tsb. */
441 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
442 }
443}
444
445int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
446{
447#ifdef CONFIG_HUGETLB_PAGE
448 unsigned long huge_pte_count;
449#endif
450 unsigned int i;
451
452 spin_lock_init(&mm->context.lock);
453
454 mm->context.sparc64_ctx_val = 0UL;
455
456#ifdef CONFIG_HUGETLB_PAGE
457 /* We reset it to zero because the fork() page copying
458 * will re-increment the counters as the parent PTEs are
459 * copied into the child address space.
460 */
461 huge_pte_count = mm->context.huge_pte_count;
462 mm->context.huge_pte_count = 0;
463#endif
464
465 /* copy_mm() copies over the parent's mm_struct before calling
466 * us, so we need to zero out the TSB pointer or else tsb_grow()
467 * will be confused and think there is an older TSB to free up.
468 */
469 for (i = 0; i < MM_NUM_TSBS; i++)
470 mm->context.tsb_block[i].tsb = NULL;
471
472 /* If this is fork, inherit the parent's TSB size. We would
473 * grow it to that size on the first page fault anyways.
474 */
475 tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm));
476
477#ifdef CONFIG_HUGETLB_PAGE
478 if (unlikely(huge_pte_count))
479 tsb_grow(mm, MM_TSB_HUGE, huge_pte_count);
480#endif
481
482 if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
483 return -ENOMEM;
484
485 return 0;
486}
487
488static void tsb_destroy_one(struct tsb_config *tp)
489{
490 unsigned long cache_index;
491
492 if (!tp->tsb)
493 return;
494 cache_index = tp->tsb_reg_val & 0x7UL;
495 kmem_cache_free(tsb_caches[cache_index], tp->tsb);
496 tp->tsb = NULL;
497 tp->tsb_reg_val = 0UL;
498}
499
500void destroy_context(struct mm_struct *mm)
501{
502 unsigned long flags, i;
503
504 for (i = 0; i < MM_NUM_TSBS; i++)
505 tsb_destroy_one(&mm->context.tsb_block[i]);
506
507 spin_lock_irqsave(&ctx_alloc_lock, flags);
508
509 if (CTX_VALID(mm->context)) {
510 unsigned long nr = CTX_NRBITS(mm->context);
511 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
512 }
513
514 spin_unlock_irqrestore(&ctx_alloc_lock, flags);
515}