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>
12 #include <asm/setup.h>
15 #include <asm/oplib.h>
17 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
19 static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
22 return vaddr & (nentries - 1);
25 static inline int tag_compare(unsigned long tag, unsigned long vaddr)
27 return (tag == (vaddr >> 22));
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.
35 void flush_tsb_kernel_range(unsigned long start, unsigned long end)
39 for (v = start; v < end; v += PAGE_SIZE) {
40 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
42 struct tsb *ent = &swapper_tsb[hash];
44 if (tag_compare(ent->tag, v))
45 ent->tag = (1UL << TSB_TAG_INVALID_BIT);
49 static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
50 unsigned long hash_shift,
51 unsigned long nentries)
53 unsigned long tag, ent, hash;
56 hash = tsb_hash(v, hash_shift, nentries);
57 ent = tsb + (hash * sizeof(struct tsb));
63 static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
64 unsigned long tsb, unsigned long nentries)
68 for (i = 0; i < tb->tlb_nr; i++)
69 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
72 void flush_tsb_user(struct tlb_batch *tb)
74 struct mm_struct *mm = tb->mm;
75 unsigned long nentries, base, flags;
77 spin_lock_irqsave(&mm->context.lock, flags);
80 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
81 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
82 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
84 __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
86 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
87 if (tb->huge && mm->context.tsb_block[MM_TSB_HUGE].tsb) {
88 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
89 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
90 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
92 __flush_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries);
95 spin_unlock_irqrestore(&mm->context.lock, flags);
98 void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr, bool huge)
100 unsigned long nentries, base, flags;
102 spin_lock_irqsave(&mm->context.lock, flags);
105 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
106 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
107 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
109 __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT, nentries);
111 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
112 if (huge && mm->context.tsb_block[MM_TSB_HUGE].tsb) {
113 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
114 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
115 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
117 __flush_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT, nentries);
120 spin_unlock_irqrestore(&mm->context.lock, flags);
123 #define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
124 #define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
126 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
127 #define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
128 #define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
131 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
133 unsigned long tsb_reg, base, tsb_paddr;
134 unsigned long page_sz, tte;
136 mm->context.tsb_block[tsb_idx].tsb_nentries =
137 tsb_bytes / sizeof(struct tsb);
141 base = TSBMAP_8K_BASE;
143 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
145 base = TSBMAP_4M_BASE;
152 tte = pgprot_val(PAGE_KERNEL_LOCKED);
153 tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
154 BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
156 /* Use the smallest page size that can map the whole TSB
162 #ifdef DCACHE_ALIASING_POSSIBLE
163 base += (tsb_paddr & 8192);
185 page_sz = 512 * 1024;
190 page_sz = 512 * 1024;
195 page_sz = 512 * 1024;
200 page_sz = 4 * 1024 * 1024;
204 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
205 current->comm, current->pid, tsb_bytes);
208 tte |= pte_sz_bits(page_sz);
210 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
211 /* Physical mapping, no locked TLB entry for TSB. */
212 tsb_reg |= tsb_paddr;
214 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
215 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
216 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
219 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
220 tte |= (tsb_paddr & ~(page_sz - 1UL));
222 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
223 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
224 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
227 /* Setup the Hypervisor TSB descriptor. */
228 if (tlb_type == hypervisor) {
229 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
233 hp->pgsz_idx = HV_PGSZ_IDX_BASE;
235 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
237 hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
244 hp->num_ttes = tsb_bytes / 16;
248 hp->pgsz_mask = HV_PGSZ_MASK_BASE;
250 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
252 hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
258 hp->tsb_base = tsb_paddr;
263 struct kmem_cache *pgtable_cache __read_mostly;
265 static struct kmem_cache *tsb_caches[8] __read_mostly;
267 static const char *tsb_cache_names[8] = {
278 void __init pgtable_cache_init(void)
282 pgtable_cache = kmem_cache_create("pgtable_cache",
283 PAGE_SIZE, PAGE_SIZE,
286 if (!pgtable_cache) {
287 prom_printf("pgtable_cache_init(): Could not create!\n");
291 for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
292 unsigned long size = 8192 << i;
293 const char *name = tsb_cache_names[i];
295 tsb_caches[i] = kmem_cache_create(name,
298 if (!tsb_caches[i]) {
299 prom_printf("Could not create %s cache\n", name);
305 int sysctl_tsb_ratio = -2;
307 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
309 unsigned long num_ents = (new_size / sizeof(struct tsb));
311 if (sysctl_tsb_ratio < 0)
312 return num_ents - (num_ents >> -sysctl_tsb_ratio);
314 return num_ents + (num_ents >> sysctl_tsb_ratio);
317 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
318 * do_sparc64_fault() invokes this routine to try and grow it.
320 * When we reach the maximum TSB size supported, we stick ~0UL into
321 * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
322 * will not trigger any longer.
324 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
325 * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
326 * must be 512K aligned. It also must be physically contiguous, so we
327 * cannot use vmalloc().
329 * The idea here is to grow the TSB when the RSS of the process approaches
330 * the number of entries that the current TSB can hold at once. Currently,
331 * we trigger when the RSS hits 3/4 of the TSB capacity.
333 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
335 unsigned long max_tsb_size = 1 * 1024 * 1024;
336 unsigned long new_size, old_size, flags;
337 struct tsb *old_tsb, *new_tsb;
338 unsigned long new_cache_index, old_cache_index;
339 unsigned long new_rss_limit;
342 if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
343 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
346 for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
347 new_rss_limit = tsb_size_to_rss_limit(new_size);
348 if (new_rss_limit > rss)
353 if (new_size == max_tsb_size)
354 new_rss_limit = ~0UL;
357 gfp_flags = GFP_KERNEL;
358 if (new_size > (PAGE_SIZE * 2))
359 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
361 new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
362 gfp_flags, numa_node_id());
363 if (unlikely(!new_tsb)) {
364 /* Not being able to fork due to a high-order TSB
365 * allocation failure is very bad behavior. Just back
366 * down to a 0-order allocation and force no TSB
367 * growing for this address space.
369 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
370 new_cache_index > 0) {
373 new_rss_limit = ~0UL;
374 goto retry_tsb_alloc;
377 /* If we failed on a TSB grow, we are under serious
378 * memory pressure so don't try to grow any more.
380 if (mm->context.tsb_block[tsb_index].tsb != NULL)
381 mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
385 /* Mark all tags as invalid. */
386 tsb_init(new_tsb, new_size);
388 /* Ok, we are about to commit the changes. If we are
389 * growing an existing TSB the locking is very tricky,
392 * We have to hold mm->context.lock while committing to the
393 * new TSB, this synchronizes us with processors in
394 * flush_tsb_user() and switch_mm() for this address space.
396 * But even with that lock held, processors run asynchronously
397 * accessing the old TSB via TLB miss handling. This is OK
398 * because those actions are just propagating state from the
399 * Linux page tables into the TSB, page table mappings are not
400 * being changed. If a real fault occurs, the processor will
401 * synchronize with us when it hits flush_tsb_user(), this is
402 * also true for the case where vmscan is modifying the page
403 * tables. The only thing we need to be careful with is to
404 * skip any locked TSB entries during copy_tsb().
406 * When we finish committing to the new TSB, we have to drop
407 * the lock and ask all other cpus running this address space
408 * to run tsb_context_switch() to see the new TSB table.
410 spin_lock_irqsave(&mm->context.lock, flags);
412 old_tsb = mm->context.tsb_block[tsb_index].tsb;
414 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
415 old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
419 /* Handle multiple threads trying to grow the TSB at the same time.
420 * One will get in here first, and bump the size and the RSS limit.
421 * The others will get in here next and hit this check.
423 if (unlikely(old_tsb &&
424 (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
425 spin_unlock_irqrestore(&mm->context.lock, flags);
427 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
431 mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
434 extern void copy_tsb(unsigned long old_tsb_base,
435 unsigned long old_tsb_size,
436 unsigned long new_tsb_base,
437 unsigned long new_tsb_size);
438 unsigned long old_tsb_base = (unsigned long) old_tsb;
439 unsigned long new_tsb_base = (unsigned long) new_tsb;
441 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
442 old_tsb_base = __pa(old_tsb_base);
443 new_tsb_base = __pa(new_tsb_base);
445 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
448 mm->context.tsb_block[tsb_index].tsb = new_tsb;
449 setup_tsb_params(mm, tsb_index, new_size);
451 spin_unlock_irqrestore(&mm->context.lock, flags);
453 /* If old_tsb is NULL, we're being invoked for the first time
454 * from init_new_context().
457 /* Reload it on the local cpu. */
458 tsb_context_switch(mm);
460 /* Now force other processors to do the same. */
465 /* Now it is safe to free the old tsb. */
466 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
470 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
472 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
473 unsigned long huge_pte_count;
477 spin_lock_init(&mm->context.lock);
479 mm->context.sparc64_ctx_val = 0UL;
481 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
482 /* We reset it to zero because the fork() page copying
483 * will re-increment the counters as the parent PTEs are
484 * copied into the child address space.
486 huge_pte_count = mm->context.huge_pte_count;
487 mm->context.huge_pte_count = 0;
490 /* copy_mm() copies over the parent's mm_struct before calling
491 * us, so we need to zero out the TSB pointer or else tsb_grow()
492 * will be confused and think there is an older TSB to free up.
494 for (i = 0; i < MM_NUM_TSBS; i++)
495 mm->context.tsb_block[i].tsb = NULL;
497 /* If this is fork, inherit the parent's TSB size. We would
498 * grow it to that size on the first page fault anyways.
500 tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm));
502 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
503 if (unlikely(huge_pte_count))
504 tsb_grow(mm, MM_TSB_HUGE, huge_pte_count);
507 if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
513 static void tsb_destroy_one(struct tsb_config *tp)
515 unsigned long cache_index;
519 cache_index = tp->tsb_reg_val & 0x7UL;
520 kmem_cache_free(tsb_caches[cache_index], tp->tsb);
522 tp->tsb_reg_val = 0UL;
525 void destroy_context(struct mm_struct *mm)
527 unsigned long flags, i;
529 for (i = 0; i < MM_NUM_TSBS; i++)
530 tsb_destroy_one(&mm->context.tsb_block[i]);
532 spin_lock_irqsave(&ctx_alloc_lock, flags);
534 if (CTX_VALID(mm->context)) {
535 unsigned long nr = CTX_NRBITS(mm->context);
536 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
539 spin_unlock_irqrestore(&ctx_alloc_lock, flags);