1 /* arch/sparc64/mm/tsb.c
3 * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
6 #include <linux/kernel.h>
7 #include <linux/preempt.h>
8 #include <linux/slab.h>
10 #include <asm/pgtable.h>
11 #include <asm/mmu_context.h>
14 #include <asm/oplib.h>
16 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
18 static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
21 return vaddr & (nentries - 1);
24 static inline int tag_compare(unsigned long tag, unsigned long vaddr)
26 return (tag == (vaddr >> 22));
29 /* TSB flushes need only occur on the processor initiating the address
30 * space modification, not on each cpu the address space has run on.
31 * Only the TLB flush needs that treatment.
34 void flush_tsb_kernel_range(unsigned long start, unsigned long end)
38 for (v = start; v < end; v += PAGE_SIZE) {
39 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
41 struct tsb *ent = &swapper_tsb[hash];
43 if (tag_compare(ent->tag, v))
44 ent->tag = (1UL << TSB_TAG_INVALID_BIT);
48 static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
49 unsigned long hash_shift,
50 unsigned long nentries)
52 unsigned long tag, ent, hash;
55 hash = tsb_hash(v, hash_shift, nentries);
56 ent = tsb + (hash * sizeof(struct tsb));
62 static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
63 unsigned long tsb, unsigned long nentries)
67 for (i = 0; i < tb->tlb_nr; i++)
68 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
71 void flush_tsb_user(struct tlb_batch *tb)
73 struct mm_struct *mm = tb->mm;
74 unsigned long nentries, base, flags;
76 spin_lock_irqsave(&mm->context.lock, flags);
78 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
79 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
80 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
82 __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
84 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
85 if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
86 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
87 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
88 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
90 __flush_tsb_one(tb, HPAGE_SHIFT, base, nentries);
93 spin_unlock_irqrestore(&mm->context.lock, flags);
96 void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr)
98 unsigned long nentries, base, flags;
100 spin_lock_irqsave(&mm->context.lock, flags);
102 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
103 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
104 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
106 __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT, nentries);
108 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
109 if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
110 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
111 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
112 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
114 __flush_tsb_one_entry(base, vaddr, HPAGE_SHIFT, nentries);
117 spin_unlock_irqrestore(&mm->context.lock, flags);
120 #define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
121 #define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
123 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
124 #define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
125 #define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
128 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
130 unsigned long tsb_reg, base, tsb_paddr;
131 unsigned long page_sz, tte;
133 mm->context.tsb_block[tsb_idx].tsb_nentries =
134 tsb_bytes / sizeof(struct tsb);
138 base = TSBMAP_8K_BASE;
140 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
142 base = TSBMAP_4M_BASE;
149 tte = pgprot_val(PAGE_KERNEL_LOCKED);
150 tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
151 BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
153 /* Use the smallest page size that can map the whole TSB
159 #ifdef DCACHE_ALIASING_POSSIBLE
160 base += (tsb_paddr & 8192);
182 page_sz = 512 * 1024;
187 page_sz = 512 * 1024;
192 page_sz = 512 * 1024;
197 page_sz = 4 * 1024 * 1024;
201 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
202 current->comm, current->pid, tsb_bytes);
205 tte |= pte_sz_bits(page_sz);
207 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
208 /* Physical mapping, no locked TLB entry for TSB. */
209 tsb_reg |= tsb_paddr;
211 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
212 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
213 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
216 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
217 tte |= (tsb_paddr & ~(page_sz - 1UL));
219 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
220 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
221 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
224 /* Setup the Hypervisor TSB descriptor. */
225 if (tlb_type == hypervisor) {
226 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
230 hp->pgsz_idx = HV_PGSZ_IDX_BASE;
232 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
234 hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
241 hp->num_ttes = tsb_bytes / 16;
245 hp->pgsz_mask = HV_PGSZ_MASK_BASE;
247 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
249 hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
255 hp->tsb_base = tsb_paddr;
260 struct kmem_cache *pgtable_cache __read_mostly;
262 static struct kmem_cache *tsb_caches[8] __read_mostly;
264 static const char *tsb_cache_names[8] = {
275 void __init pgtable_cache_init(void)
279 pgtable_cache = kmem_cache_create("pgtable_cache",
280 PAGE_SIZE, PAGE_SIZE,
283 if (!pgtable_cache) {
284 prom_printf("pgtable_cache_init(): Could not create!\n");
288 for (i = 0; i < 8; i++) {
289 unsigned long size = 8192 << i;
290 const char *name = tsb_cache_names[i];
292 tsb_caches[i] = kmem_cache_create(name,
295 if (!tsb_caches[i]) {
296 prom_printf("Could not create %s cache\n", name);
302 int sysctl_tsb_ratio = -2;
304 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
306 unsigned long num_ents = (new_size / sizeof(struct tsb));
308 if (sysctl_tsb_ratio < 0)
309 return num_ents - (num_ents >> -sysctl_tsb_ratio);
311 return num_ents + (num_ents >> sysctl_tsb_ratio);
314 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
315 * do_sparc64_fault() invokes this routine to try and grow it.
317 * When we reach the maximum TSB size supported, we stick ~0UL into
318 * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
319 * will not trigger any longer.
321 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
322 * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
323 * must be 512K aligned. It also must be physically contiguous, so we
324 * cannot use vmalloc().
326 * The idea here is to grow the TSB when the RSS of the process approaches
327 * the number of entries that the current TSB can hold at once. Currently,
328 * we trigger when the RSS hits 3/4 of the TSB capacity.
330 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
332 unsigned long max_tsb_size = 1 * 1024 * 1024;
333 unsigned long new_size, old_size, flags;
334 struct tsb *old_tsb, *new_tsb;
335 unsigned long new_cache_index, old_cache_index;
336 unsigned long new_rss_limit;
339 if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
340 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
343 for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
344 new_rss_limit = tsb_size_to_rss_limit(new_size);
345 if (new_rss_limit > rss)
350 if (new_size == max_tsb_size)
351 new_rss_limit = ~0UL;
354 gfp_flags = GFP_KERNEL;
355 if (new_size > (PAGE_SIZE * 2))
356 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
358 new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
359 gfp_flags, numa_node_id());
360 if (unlikely(!new_tsb)) {
361 /* Not being able to fork due to a high-order TSB
362 * allocation failure is very bad behavior. Just back
363 * down to a 0-order allocation and force no TSB
364 * growing for this address space.
366 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
367 new_cache_index > 0) {
370 new_rss_limit = ~0UL;
371 goto retry_tsb_alloc;
374 /* If we failed on a TSB grow, we are under serious
375 * memory pressure so don't try to grow any more.
377 if (mm->context.tsb_block[tsb_index].tsb != NULL)
378 mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
382 /* Mark all tags as invalid. */
383 tsb_init(new_tsb, new_size);
385 /* Ok, we are about to commit the changes. If we are
386 * growing an existing TSB the locking is very tricky,
389 * We have to hold mm->context.lock while committing to the
390 * new TSB, this synchronizes us with processors in
391 * flush_tsb_user() and switch_mm() for this address space.
393 * But even with that lock held, processors run asynchronously
394 * accessing the old TSB via TLB miss handling. This is OK
395 * because those actions are just propagating state from the
396 * Linux page tables into the TSB, page table mappings are not
397 * being changed. If a real fault occurs, the processor will
398 * synchronize with us when it hits flush_tsb_user(), this is
399 * also true for the case where vmscan is modifying the page
400 * tables. The only thing we need to be careful with is to
401 * skip any locked TSB entries during copy_tsb().
403 * When we finish committing to the new TSB, we have to drop
404 * the lock and ask all other cpus running this address space
405 * to run tsb_context_switch() to see the new TSB table.
407 spin_lock_irqsave(&mm->context.lock, flags);
409 old_tsb = mm->context.tsb_block[tsb_index].tsb;
411 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
412 old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
416 /* Handle multiple threads trying to grow the TSB at the same time.
417 * One will get in here first, and bump the size and the RSS limit.
418 * The others will get in here next and hit this check.
420 if (unlikely(old_tsb &&
421 (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
422 spin_unlock_irqrestore(&mm->context.lock, flags);
424 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
428 mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
431 extern void copy_tsb(unsigned long old_tsb_base,
432 unsigned long old_tsb_size,
433 unsigned long new_tsb_base,
434 unsigned long new_tsb_size);
435 unsigned long old_tsb_base = (unsigned long) old_tsb;
436 unsigned long new_tsb_base = (unsigned long) new_tsb;
438 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
439 old_tsb_base = __pa(old_tsb_base);
440 new_tsb_base = __pa(new_tsb_base);
442 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
445 mm->context.tsb_block[tsb_index].tsb = new_tsb;
446 setup_tsb_params(mm, tsb_index, new_size);
448 spin_unlock_irqrestore(&mm->context.lock, flags);
450 /* If old_tsb is NULL, we're being invoked for the first time
451 * from init_new_context().
454 /* Reload it on the local cpu. */
455 tsb_context_switch(mm);
457 /* Now force other processors to do the same. */
462 /* Now it is safe to free the old tsb. */
463 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
467 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
469 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
470 unsigned long huge_pte_count;
474 spin_lock_init(&mm->context.lock);
476 mm->context.sparc64_ctx_val = 0UL;
478 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
479 /* We reset it to zero because the fork() page copying
480 * will re-increment the counters as the parent PTEs are
481 * copied into the child address space.
483 huge_pte_count = mm->context.huge_pte_count;
484 mm->context.huge_pte_count = 0;
487 mm->context.pgtable_page = NULL;
489 /* copy_mm() copies over the parent's mm_struct before calling
490 * us, so we need to zero out the TSB pointer or else tsb_grow()
491 * will be confused and think there is an older TSB to free up.
493 for (i = 0; i < MM_NUM_TSBS; i++)
494 mm->context.tsb_block[i].tsb = NULL;
496 /* If this is fork, inherit the parent's TSB size. We would
497 * grow it to that size on the first page fault anyways.
499 tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm));
501 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
502 if (unlikely(huge_pte_count))
503 tsb_grow(mm, MM_TSB_HUGE, huge_pte_count);
506 if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
512 static void tsb_destroy_one(struct tsb_config *tp)
514 unsigned long cache_index;
518 cache_index = tp->tsb_reg_val & 0x7UL;
519 kmem_cache_free(tsb_caches[cache_index], tp->tsb);
521 tp->tsb_reg_val = 0UL;
524 void destroy_context(struct mm_struct *mm)
526 unsigned long flags, i;
529 for (i = 0; i < MM_NUM_TSBS; i++)
530 tsb_destroy_one(&mm->context.tsb_block[i]);
532 page = mm->context.pgtable_page;
533 if (page && put_page_testzero(page)) {
534 pgtable_page_dtor(page);
535 free_hot_cold_page(page, 0);
538 spin_lock_irqsave(&ctx_alloc_lock, flags);
540 if (CTX_VALID(mm->context)) {
541 unsigned long nr = CTX_NRBITS(mm->context);
542 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
545 spin_unlock_irqrestore(&ctx_alloc_lock, flags);