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/tlbflush.h>
12 #include <asm/mmu_context.h>
13 #include <asm/pgtable.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(struct tlb_batch *tb, unsigned long hash_shift,
50 unsigned long tsb, unsigned long nentries)
54 for (i = 0; i < tb->tlb_nr; i++) {
55 unsigned long v = tb->vaddrs[i];
56 unsigned long tag, ent, hash;
60 hash = tsb_hash(v, hash_shift, nentries);
61 ent = tsb + (hash * sizeof(struct tsb));
68 void flush_tsb_user(struct tlb_batch *tb)
70 struct mm_struct *mm = tb->mm;
71 unsigned long nentries, base, flags;
73 spin_lock_irqsave(&mm->context.lock, flags);
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)
79 __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
81 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
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)
87 __flush_tsb_one(tb, HPAGE_SHIFT, base, nentries);
90 spin_unlock_irqrestore(&mm->context.lock, flags);
93 #define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
94 #define HV_PGSZ_MASK_BASE HV_PGSZ_MASK_8K
96 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
97 #define HV_PGSZ_IDX_HUGE HV_PGSZ_IDX_4MB
98 #define HV_PGSZ_MASK_HUGE HV_PGSZ_MASK_4MB
101 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
103 unsigned long tsb_reg, base, tsb_paddr;
104 unsigned long page_sz, tte;
106 mm->context.tsb_block[tsb_idx].tsb_nentries =
107 tsb_bytes / sizeof(struct tsb);
110 tte = pgprot_val(PAGE_KERNEL_LOCKED);
111 tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
112 BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
114 /* Use the smallest page size that can map the whole TSB
120 #ifdef DCACHE_ALIASING_POSSIBLE
121 base += (tsb_paddr & 8192);
143 page_sz = 512 * 1024;
148 page_sz = 512 * 1024;
153 page_sz = 512 * 1024;
158 page_sz = 4 * 1024 * 1024;
162 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
163 current->comm, current->pid, tsb_bytes);
166 tte |= pte_sz_bits(page_sz);
168 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
169 /* Physical mapping, no locked TLB entry for TSB. */
170 tsb_reg |= tsb_paddr;
172 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
173 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
174 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
177 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
178 tte |= (tsb_paddr & ~(page_sz - 1UL));
180 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
181 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
182 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
185 /* Setup the Hypervisor TSB descriptor. */
186 if (tlb_type == hypervisor) {
187 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
191 hp->pgsz_idx = HV_PGSZ_IDX_BASE;
193 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
195 hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
202 hp->num_ttes = tsb_bytes / 16;
206 hp->pgsz_mask = HV_PGSZ_MASK_BASE;
208 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
210 hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
216 hp->tsb_base = tsb_paddr;
221 struct kmem_cache *pgtable_cache __read_mostly;
223 static struct kmem_cache *tsb_caches[8] __read_mostly;
225 static const char *tsb_cache_names[8] = {
236 void __init pgtable_cache_init(void)
240 pgtable_cache = kmem_cache_create("pgtable_cache",
241 PAGE_SIZE, PAGE_SIZE,
244 if (!pgtable_cache) {
245 prom_printf("pgtable_cache_init(): Could not create!\n");
249 for (i = 0; i < 8; i++) {
250 unsigned long size = 8192 << i;
251 const char *name = tsb_cache_names[i];
253 tsb_caches[i] = kmem_cache_create(name,
256 if (!tsb_caches[i]) {
257 prom_printf("Could not create %s cache\n", name);
263 int sysctl_tsb_ratio = -2;
265 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
267 unsigned long num_ents = (new_size / sizeof(struct tsb));
269 if (sysctl_tsb_ratio < 0)
270 return num_ents - (num_ents >> -sysctl_tsb_ratio);
272 return num_ents + (num_ents >> sysctl_tsb_ratio);
275 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
276 * do_sparc64_fault() invokes this routine to try and grow it.
278 * When we reach the maximum TSB size supported, we stick ~0UL into
279 * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
280 * will not trigger any longer.
282 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
283 * of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
284 * must be 512K aligned. It also must be physically contiguous, so we
285 * cannot use vmalloc().
287 * The idea here is to grow the TSB when the RSS of the process approaches
288 * the number of entries that the current TSB can hold at once. Currently,
289 * we trigger when the RSS hits 3/4 of the TSB capacity.
291 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
293 unsigned long max_tsb_size = 1 * 1024 * 1024;
294 unsigned long new_size, old_size, flags;
295 struct tsb *old_tsb, *new_tsb;
296 unsigned long new_cache_index, old_cache_index;
297 unsigned long new_rss_limit;
300 if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
301 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
304 for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
305 new_rss_limit = tsb_size_to_rss_limit(new_size);
306 if (new_rss_limit > rss)
311 if (new_size == max_tsb_size)
312 new_rss_limit = ~0UL;
315 gfp_flags = GFP_KERNEL;
316 if (new_size > (PAGE_SIZE * 2))
317 gfp_flags = __GFP_NOWARN | __GFP_NORETRY;
319 new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
320 gfp_flags, numa_node_id());
321 if (unlikely(!new_tsb)) {
322 /* Not being able to fork due to a high-order TSB
323 * allocation failure is very bad behavior. Just back
324 * down to a 0-order allocation and force no TSB
325 * growing for this address space.
327 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
328 new_cache_index > 0) {
331 new_rss_limit = ~0UL;
332 goto retry_tsb_alloc;
335 /* If we failed on a TSB grow, we are under serious
336 * memory pressure so don't try to grow any more.
338 if (mm->context.tsb_block[tsb_index].tsb != NULL)
339 mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
343 /* Mark all tags as invalid. */
344 tsb_init(new_tsb, new_size);
346 /* Ok, we are about to commit the changes. If we are
347 * growing an existing TSB the locking is very tricky,
350 * We have to hold mm->context.lock while committing to the
351 * new TSB, this synchronizes us with processors in
352 * flush_tsb_user() and switch_mm() for this address space.
354 * But even with that lock held, processors run asynchronously
355 * accessing the old TSB via TLB miss handling. This is OK
356 * because those actions are just propagating state from the
357 * Linux page tables into the TSB, page table mappings are not
358 * being changed. If a real fault occurs, the processor will
359 * synchronize with us when it hits flush_tsb_user(), this is
360 * also true for the case where vmscan is modifying the page
361 * tables. The only thing we need to be careful with is to
362 * skip any locked TSB entries during copy_tsb().
364 * When we finish committing to the new TSB, we have to drop
365 * the lock and ask all other cpus running this address space
366 * to run tsb_context_switch() to see the new TSB table.
368 spin_lock_irqsave(&mm->context.lock, flags);
370 old_tsb = mm->context.tsb_block[tsb_index].tsb;
372 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
373 old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
377 /* Handle multiple threads trying to grow the TSB at the same time.
378 * One will get in here first, and bump the size and the RSS limit.
379 * The others will get in here next and hit this check.
381 if (unlikely(old_tsb &&
382 (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
383 spin_unlock_irqrestore(&mm->context.lock, flags);
385 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
389 mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
392 extern void copy_tsb(unsigned long old_tsb_base,
393 unsigned long old_tsb_size,
394 unsigned long new_tsb_base,
395 unsigned long new_tsb_size);
396 unsigned long old_tsb_base = (unsigned long) old_tsb;
397 unsigned long new_tsb_base = (unsigned long) new_tsb;
399 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
400 old_tsb_base = __pa(old_tsb_base);
401 new_tsb_base = __pa(new_tsb_base);
403 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
406 mm->context.tsb_block[tsb_index].tsb = new_tsb;
407 setup_tsb_params(mm, tsb_index, new_size);
409 spin_unlock_irqrestore(&mm->context.lock, flags);
411 /* If old_tsb is NULL, we're being invoked for the first time
412 * from init_new_context().
415 /* Reload it on the local cpu. */
416 tsb_context_switch(mm);
418 /* Now force other processors to do the same. */
423 /* Now it is safe to free the old tsb. */
424 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
428 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
430 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
431 unsigned long huge_pte_count;
435 spin_lock_init(&mm->context.lock);
437 mm->context.sparc64_ctx_val = 0UL;
439 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
440 /* We reset it to zero because the fork() page copying
441 * will re-increment the counters as the parent PTEs are
442 * copied into the child address space.
444 huge_pte_count = mm->context.huge_pte_count;
445 mm->context.huge_pte_count = 0;
448 mm->context.pgtable_page = NULL;
450 /* copy_mm() copies over the parent's mm_struct before calling
451 * us, so we need to zero out the TSB pointer or else tsb_grow()
452 * will be confused and think there is an older TSB to free up.
454 for (i = 0; i < MM_NUM_TSBS; i++)
455 mm->context.tsb_block[i].tsb = NULL;
457 /* If this is fork, inherit the parent's TSB size. We would
458 * grow it to that size on the first page fault anyways.
460 tsb_grow(mm, MM_TSB_BASE, get_mm_rss(mm));
462 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
463 if (unlikely(huge_pte_count))
464 tsb_grow(mm, MM_TSB_HUGE, huge_pte_count);
467 if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
473 static void tsb_destroy_one(struct tsb_config *tp)
475 unsigned long cache_index;
479 cache_index = tp->tsb_reg_val & 0x7UL;
480 kmem_cache_free(tsb_caches[cache_index], tp->tsb);
482 tp->tsb_reg_val = 0UL;
485 void destroy_context(struct mm_struct *mm)
487 unsigned long flags, i;
490 for (i = 0; i < MM_NUM_TSBS; i++)
491 tsb_destroy_one(&mm->context.tsb_block[i]);
493 page = mm->context.pgtable_page;
494 if (page && put_page_testzero(page)) {
495 pgtable_page_dtor(page);
496 free_hot_cold_page(page, 0);
499 spin_lock_irqsave(&ctx_alloc_lock, flags);
501 if (CTX_VALID(mm->context)) {
502 unsigned long nr = CTX_NRBITS(mm->context);
503 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
506 spin_unlock_irqrestore(&ctx_alloc_lock, flags);