summaryrefslogtreecommitdiff
path: root/arch/s390/mm/pgalloc.c
blob: 5b15b45941c6ced3d508096dea450b1c9fe5b642 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
// SPDX-License-Identifier: GPL-2.0
/*
 *  Page table allocation functions
 *
 *    Copyright IBM Corp. 2016
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <asm/mmu_context.h>
#include <asm/page-states.h>
#include <asm/pgalloc.h>
#include <asm/gmap.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>

#ifdef CONFIG_PGSTE

int page_table_allocate_pgste = 0;
EXPORT_SYMBOL(page_table_allocate_pgste);

static struct ctl_table page_table_sysctl[] = {
	{
		.procname	= "allocate_pgste",
		.data		= &page_table_allocate_pgste,
		.maxlen		= sizeof(int),
		.mode		= S_IRUGO | S_IWUSR,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_ONE,
	},
};

static int __init page_table_register_sysctl(void)
{
	return register_sysctl("vm", page_table_sysctl) ? 0 : -ENOMEM;
}
__initcall(page_table_register_sysctl);

#endif /* CONFIG_PGSTE */

unsigned long *crst_table_alloc(struct mm_struct *mm)
{
	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
	unsigned long *table;

	if (!ptdesc)
		return NULL;
	table = ptdesc_to_virt(ptdesc);
	__arch_set_page_dat(table, 1UL << CRST_ALLOC_ORDER);
	return table;
}

void crst_table_free(struct mm_struct *mm, unsigned long *table)
{
	pagetable_free(virt_to_ptdesc(table));
}

static void __crst_table_upgrade(void *arg)
{
	struct mm_struct *mm = arg;

	/* change all active ASCEs to avoid the creation of new TLBs */
	if (current->active_mm == mm) {
		S390_lowcore.user_asce.val = mm->context.asce;
		local_ctl_load(7, &S390_lowcore.user_asce);
	}
	__tlb_flush_local();
}

int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
{
	unsigned long *pgd = NULL, *p4d = NULL, *__pgd;
	unsigned long asce_limit = mm->context.asce_limit;

	/* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
	VM_BUG_ON(asce_limit < _REGION2_SIZE);

	if (end <= asce_limit)
		return 0;

	if (asce_limit == _REGION2_SIZE) {
		p4d = crst_table_alloc(mm);
		if (unlikely(!p4d))
			goto err_p4d;
		crst_table_init(p4d, _REGION2_ENTRY_EMPTY);
	}
	if (end > _REGION1_SIZE) {
		pgd = crst_table_alloc(mm);
		if (unlikely(!pgd))
			goto err_pgd;
		crst_table_init(pgd, _REGION1_ENTRY_EMPTY);
	}

	spin_lock_bh(&mm->page_table_lock);

	/*
	 * This routine gets called with mmap_lock lock held and there is
	 * no reason to optimize for the case of otherwise. However, if
	 * that would ever change, the below check will let us know.
	 */
	VM_BUG_ON(asce_limit != mm->context.asce_limit);

	if (p4d) {
		__pgd = (unsigned long *) mm->pgd;
		p4d_populate(mm, (p4d_t *) p4d, (pud_t *) __pgd);
		mm->pgd = (pgd_t *) p4d;
		mm->context.asce_limit = _REGION1_SIZE;
		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
			_ASCE_USER_BITS | _ASCE_TYPE_REGION2;
		mm_inc_nr_puds(mm);
	}
	if (pgd) {
		__pgd = (unsigned long *) mm->pgd;
		pgd_populate(mm, (pgd_t *) pgd, (p4d_t *) __pgd);
		mm->pgd = (pgd_t *) pgd;
		mm->context.asce_limit = TASK_SIZE_MAX;
		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
			_ASCE_USER_BITS | _ASCE_TYPE_REGION1;
	}

	spin_unlock_bh(&mm->page_table_lock);

	on_each_cpu(__crst_table_upgrade, mm, 0);

	return 0;

err_pgd:
	crst_table_free(mm, p4d);
err_p4d:
	return -ENOMEM;
}

#ifdef CONFIG_PGSTE

struct page *page_table_alloc_pgste(struct mm_struct *mm)
{
	struct ptdesc *ptdesc;
	u64 *table;

	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
	if (ptdesc) {
		table = (u64 *)ptdesc_to_virt(ptdesc);
		__arch_set_page_dat(table, 1);
		memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
		memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
	}
	return ptdesc_page(ptdesc);
}

void page_table_free_pgste(struct page *page)
{
	pagetable_free(page_ptdesc(page));
}

#endif /* CONFIG_PGSTE */

unsigned long *page_table_alloc(struct mm_struct *mm)
{
	struct ptdesc *ptdesc;
	unsigned long *table;

	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
	if (!ptdesc)
		return NULL;
	if (!pagetable_pte_ctor(ptdesc)) {
		pagetable_free(ptdesc);
		return NULL;
	}
	table = ptdesc_to_virt(ptdesc);
	__arch_set_page_dat(table, 1);
	/* pt_list is used by gmap only */
	INIT_LIST_HEAD(&ptdesc->pt_list);
	memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
	memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
	return table;
}

static void pagetable_pte_dtor_free(struct ptdesc *ptdesc)
{
	pagetable_pte_dtor(ptdesc);
	pagetable_free(ptdesc);
}

void page_table_free(struct mm_struct *mm, unsigned long *table)
{
	struct ptdesc *ptdesc = virt_to_ptdesc(table);

	pagetable_pte_dtor_free(ptdesc);
}

void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
			 unsigned long vmaddr)
{
	struct mm_struct *mm;

	mm = tlb->mm;
	if (mm_alloc_pgste(mm))
		gmap_unlink(mm, table, vmaddr);
	table = (unsigned long *)((unsigned long)table | 0x01U);
	tlb_remove_ptdesc(tlb, table);
}

void __tlb_remove_table(void *_table)
{
	struct ptdesc *ptdesc;
	unsigned int mask;
	void *table;

	mask = (unsigned long)_table & 0x01U;
	table = (void *)((unsigned long)_table ^ mask);
	ptdesc = virt_to_ptdesc(table);
	if (!mask) {
		/* pmd, pud, or p4d */
		pagetable_free(ptdesc);
		return;
	}
	pagetable_pte_dtor_free(ptdesc);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void pte_free_now(struct rcu_head *head)
{
	struct ptdesc *ptdesc = container_of(head, struct ptdesc, pt_rcu_head);

	pagetable_pte_dtor_free(ptdesc);
}

void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
{
	struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);

	call_rcu(&ptdesc->pt_rcu_head, pte_free_now);
	/*
	 * THPs are not allowed for KVM guests. Warn if pgste ever reaches here.
	 * Turn to the generic pte_free_defer() version once gmap is removed.
	 */
	WARN_ON_ONCE(mm_has_pgste(mm));
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

/*
 * Base infrastructure required to generate basic asces, region, segment,
 * and page tables that do not make use of enhanced features like EDAT1.
 */

static struct kmem_cache *base_pgt_cache;

static unsigned long *base_pgt_alloc(void)
{
	unsigned long *table;

	table = kmem_cache_alloc(base_pgt_cache, GFP_KERNEL);
	if (table)
		memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
	return table;
}

static void base_pgt_free(unsigned long *table)
{
	kmem_cache_free(base_pgt_cache, table);
}

static unsigned long *base_crst_alloc(unsigned long val)
{
	unsigned long *table;
	struct ptdesc *ptdesc;

	ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
	if (!ptdesc)
		return NULL;
	table = ptdesc_address(ptdesc);
	crst_table_init(table, val);
	return table;
}

static void base_crst_free(unsigned long *table)
{
	pagetable_free(virt_to_ptdesc(table));
}

#define BASE_ADDR_END_FUNC(NAME, SIZE)					\
static inline unsigned long base_##NAME##_addr_end(unsigned long addr,	\
						   unsigned long end)	\
{									\
	unsigned long next = (addr + (SIZE)) & ~((SIZE) - 1);		\
									\
	return (next - 1) < (end - 1) ? next : end;			\
}

BASE_ADDR_END_FUNC(page,    _PAGE_SIZE)
BASE_ADDR_END_FUNC(segment, _SEGMENT_SIZE)
BASE_ADDR_END_FUNC(region3, _REGION3_SIZE)
BASE_ADDR_END_FUNC(region2, _REGION2_SIZE)
BASE_ADDR_END_FUNC(region1, _REGION1_SIZE)

static inline unsigned long base_lra(unsigned long address)
{
	unsigned long real;

	asm volatile(
		"	lra	%0,0(%1)\n"
		: "=d" (real) : "a" (address) : "cc");
	return real;
}

static int base_page_walk(unsigned long *origin, unsigned long addr,
			  unsigned long end, int alloc)
{
	unsigned long *pte, next;

	if (!alloc)
		return 0;
	pte = origin;
	pte += (addr & _PAGE_INDEX) >> _PAGE_SHIFT;
	do {
		next = base_page_addr_end(addr, end);
		*pte = base_lra(addr);
	} while (pte++, addr = next, addr < end);
	return 0;
}

static int base_segment_walk(unsigned long *origin, unsigned long addr,
			     unsigned long end, int alloc)
{
	unsigned long *ste, next, *table;
	int rc;

	ste = origin;
	ste += (addr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
	do {
		next = base_segment_addr_end(addr, end);
		if (*ste & _SEGMENT_ENTRY_INVALID) {
			if (!alloc)
				continue;
			table = base_pgt_alloc();
			if (!table)
				return -ENOMEM;
			*ste = __pa(table) | _SEGMENT_ENTRY;
		}
		table = __va(*ste & _SEGMENT_ENTRY_ORIGIN);
		rc = base_page_walk(table, addr, next, alloc);
		if (rc)
			return rc;
		if (!alloc)
			base_pgt_free(table);
		cond_resched();
	} while (ste++, addr = next, addr < end);
	return 0;
}

static int base_region3_walk(unsigned long *origin, unsigned long addr,
			     unsigned long end, int alloc)
{
	unsigned long *rtte, next, *table;
	int rc;

	rtte = origin;
	rtte += (addr & _REGION3_INDEX) >> _REGION3_SHIFT;
	do {
		next = base_region3_addr_end(addr, end);
		if (*rtte & _REGION_ENTRY_INVALID) {
			if (!alloc)
				continue;
			table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
			if (!table)
				return -ENOMEM;
			*rtte = __pa(table) | _REGION3_ENTRY;
		}
		table = __va(*rtte & _REGION_ENTRY_ORIGIN);
		rc = base_segment_walk(table, addr, next, alloc);
		if (rc)
			return rc;
		if (!alloc)
			base_crst_free(table);
	} while (rtte++, addr = next, addr < end);
	return 0;
}

static int base_region2_walk(unsigned long *origin, unsigned long addr,
			     unsigned long end, int alloc)
{
	unsigned long *rste, next, *table;
	int rc;

	rste = origin;
	rste += (addr & _REGION2_INDEX) >> _REGION2_SHIFT;
	do {
		next = base_region2_addr_end(addr, end);
		if (*rste & _REGION_ENTRY_INVALID) {
			if (!alloc)
				continue;
			table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
			if (!table)
				return -ENOMEM;
			*rste = __pa(table) | _REGION2_ENTRY;
		}
		table = __va(*rste & _REGION_ENTRY_ORIGIN);
		rc = base_region3_walk(table, addr, next, alloc);
		if (rc)
			return rc;
		if (!alloc)
			base_crst_free(table);
	} while (rste++, addr = next, addr < end);
	return 0;
}

static int base_region1_walk(unsigned long *origin, unsigned long addr,
			     unsigned long end, int alloc)
{
	unsigned long *rfte, next, *table;
	int rc;

	rfte = origin;
	rfte += (addr & _REGION1_INDEX) >> _REGION1_SHIFT;
	do {
		next = base_region1_addr_end(addr, end);
		if (*rfte & _REGION_ENTRY_INVALID) {
			if (!alloc)
				continue;
			table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
			if (!table)
				return -ENOMEM;
			*rfte = __pa(table) | _REGION1_ENTRY;
		}
		table = __va(*rfte & _REGION_ENTRY_ORIGIN);
		rc = base_region2_walk(table, addr, next, alloc);
		if (rc)
			return rc;
		if (!alloc)
			base_crst_free(table);
	} while (rfte++, addr = next, addr < end);
	return 0;
}

/**
 * base_asce_free - free asce and tables returned from base_asce_alloc()
 * @asce: asce to be freed
 *
 * Frees all region, segment, and page tables that were allocated with a
 * corresponding base_asce_alloc() call.
 */
void base_asce_free(unsigned long asce)
{
	unsigned long *table = __va(asce & _ASCE_ORIGIN);

	if (!asce)
		return;
	switch (asce & _ASCE_TYPE_MASK) {
	case _ASCE_TYPE_SEGMENT:
		base_segment_walk(table, 0, _REGION3_SIZE, 0);
		break;
	case _ASCE_TYPE_REGION3:
		base_region3_walk(table, 0, _REGION2_SIZE, 0);
		break;
	case _ASCE_TYPE_REGION2:
		base_region2_walk(table, 0, _REGION1_SIZE, 0);
		break;
	case _ASCE_TYPE_REGION1:
		base_region1_walk(table, 0, TASK_SIZE_MAX, 0);
		break;
	}
	base_crst_free(table);
}

static int base_pgt_cache_init(void)
{
	static DEFINE_MUTEX(base_pgt_cache_mutex);
	unsigned long sz = _PAGE_TABLE_SIZE;

	if (base_pgt_cache)
		return 0;
	mutex_lock(&base_pgt_cache_mutex);
	if (!base_pgt_cache)
		base_pgt_cache = kmem_cache_create("base_pgt", sz, sz, 0, NULL);
	mutex_unlock(&base_pgt_cache_mutex);
	return base_pgt_cache ? 0 : -ENOMEM;
}

/**
 * base_asce_alloc - create kernel mapping without enhanced DAT features
 * @addr: virtual start address of kernel mapping
 * @num_pages: number of consecutive pages
 *
 * Generate an asce, including all required region, segment and page tables,
 * that can be used to access the virtual kernel mapping. The difference is
 * that the returned asce does not make use of any enhanced DAT features like
 * e.g. large pages. This is required for some I/O functions that pass an
 * asce, like e.g. some service call requests.
 *
 * Note: the returned asce may NEVER be attached to any cpu. It may only be
 *	 used for I/O requests. tlb entries that might result because the
 *	 asce was attached to a cpu won't be cleared.
 */
unsigned long base_asce_alloc(unsigned long addr, unsigned long num_pages)
{
	unsigned long asce, *table, end;
	int rc;

	if (base_pgt_cache_init())
		return 0;
	end = addr + num_pages * PAGE_SIZE;
	if (end <= _REGION3_SIZE) {
		table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
		if (!table)
			return 0;
		rc = base_segment_walk(table, addr, end, 1);
		asce = __pa(table) | _ASCE_TYPE_SEGMENT | _ASCE_TABLE_LENGTH;
	} else if (end <= _REGION2_SIZE) {
		table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
		if (!table)
			return 0;
		rc = base_region3_walk(table, addr, end, 1);
		asce = __pa(table) | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
	} else if (end <= _REGION1_SIZE) {
		table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
		if (!table)
			return 0;
		rc = base_region2_walk(table, addr, end, 1);
		asce = __pa(table) | _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
	} else {
		table = base_crst_alloc(_REGION1_ENTRY_EMPTY);
		if (!table)
			return 0;
		rc = base_region1_walk(table, addr, end, 1);
		asce = __pa(table) | _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH;
	}
	if (rc) {
		base_asce_free(asce);
		asce = 0;
	}
	return asce;
}