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