summaryrefslogtreecommitdiff
path: root/arch/tile/mm/pgtable.c
blob: 2c850d9864e38b8b7e4c4163853c4c6704bd7908 (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
/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <linux/smp.h>

#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/homecache.h>

#define K(x) ((x) << (PAGE_SHIFT-10))

/*
 * The normal show_free_areas() is too verbose on Tile, with dozens
 * of processors and often four NUMA zones each with high and lowmem.
 */
void show_mem(void)
{
	struct zone *zone;

	pr_err("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu"
	       " free:%lu\n slab:%lu mapped:%lu pagetables:%lu bounce:%lu"
	       " pagecache:%lu swap:%lu\n",
	       (global_page_state(NR_ACTIVE_ANON) +
		global_page_state(NR_ACTIVE_FILE)),
	       (global_page_state(NR_INACTIVE_ANON) +
		global_page_state(NR_INACTIVE_FILE)),
	       global_page_state(NR_FILE_DIRTY),
	       global_page_state(NR_WRITEBACK),
	       global_page_state(NR_UNSTABLE_NFS),
	       global_page_state(NR_FREE_PAGES),
	       (global_page_state(NR_SLAB_RECLAIMABLE) +
		global_page_state(NR_SLAB_UNRECLAIMABLE)),
	       global_page_state(NR_FILE_MAPPED),
	       global_page_state(NR_PAGETABLE),
	       global_page_state(NR_BOUNCE),
	       global_page_state(NR_FILE_PAGES),
	       nr_swap_pages);

	for_each_zone(zone) {
		unsigned long flags, order, total = 0, largest_order = -1;

		if (!populated_zone(zone))
			continue;

		spin_lock_irqsave(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
			int nr = zone->free_area[order].nr_free;
			total += nr << order;
			if (nr)
				largest_order = order;
		}
		spin_unlock_irqrestore(&zone->lock, flags);
		pr_err("Node %d %7s: %lukB (largest %luKb)\n",
		       zone_to_nid(zone), zone->name,
		       K(total), largest_order ? K(1UL) << largest_order : 0);
	}
}

/*
 * Associate a virtual page frame with a given physical page frame
 * and protection flags for that frame.
 */
static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	pgd = swapper_pg_dir + pgd_index(vaddr);
	if (pgd_none(*pgd)) {
		BUG();
		return;
	}
	pud = pud_offset(pgd, vaddr);
	if (pud_none(*pud)) {
		BUG();
		return;
	}
	pmd = pmd_offset(pud, vaddr);
	if (pmd_none(*pmd)) {
		BUG();
		return;
	}
	pte = pte_offset_kernel(pmd, vaddr);
	/* <pfn,flags> stored as-is, to permit clearing entries */
	set_pte(pte, pfn_pte(pfn, flags));

	/*
	 * It's enough to flush this one mapping.
	 * This appears conservative since it is only called
	 * from __set_fixmap.
	 */
	local_flush_tlb_page(NULL, vaddr, PAGE_SIZE);
}

void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
{
	unsigned long address = __fix_to_virt(idx);

	if (idx >= __end_of_fixed_addresses) {
		BUG();
		return;
	}
	set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
}

#if defined(CONFIG_HIGHPTE)
pte_t *_pte_offset_map(pmd_t *dir, unsigned long address)
{
	pte_t *pte = kmap_atomic(pmd_page(*dir)) +
		(pmd_ptfn(*dir) << HV_LOG2_PAGE_TABLE_ALIGN) & ~PAGE_MASK;
	return &pte[pte_index(address)];
}
#endif

/*
 * List of all pgd's needed so it can invalidate entries in both cached
 * and uncached pgd's. This is essentially codepath-based locking
 * against pageattr.c; it is the unique case in which a valid change
 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
 * vmalloc faults work because attached pagetables are never freed.
 * The locking scheme was chosen on the basis of manfred's
 * recommendations and having no core impact whatsoever.
 * -- wli
 */
DEFINE_SPINLOCK(pgd_lock);
LIST_HEAD(pgd_list);

static inline void pgd_list_add(pgd_t *pgd)
{
	list_add(pgd_to_list(pgd), &pgd_list);
}

static inline void pgd_list_del(pgd_t *pgd)
{
	list_del(pgd_to_list(pgd));
}

#define KERNEL_PGD_INDEX_START pgd_index(PAGE_OFFSET)
#define KERNEL_PGD_PTRS (PTRS_PER_PGD - KERNEL_PGD_INDEX_START)

static void pgd_ctor(pgd_t *pgd)
{
	unsigned long flags;

	memset(pgd, 0, KERNEL_PGD_INDEX_START*sizeof(pgd_t));
	spin_lock_irqsave(&pgd_lock, flags);

#ifndef __tilegx__
	/*
	 * Check that the user interrupt vector has no L2.
	 * It never should for the swapper, and new page tables
	 * should always start with an empty user interrupt vector.
	 */
	BUG_ON(((u64 *)swapper_pg_dir)[pgd_index(MEM_USER_INTRPT)] != 0);
#endif

	clone_pgd_range(pgd + KERNEL_PGD_INDEX_START,
			swapper_pg_dir + KERNEL_PGD_INDEX_START,
			KERNEL_PGD_PTRS);

	pgd_list_add(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
}

static void pgd_dtor(pgd_t *pgd)
{
	unsigned long flags; /* can be called from interrupt context */

	spin_lock_irqsave(&pgd_lock, flags);
	pgd_list_del(pgd);
	spin_unlock_irqrestore(&pgd_lock, flags);
}

pgd_t *pgd_alloc(struct mm_struct *mm)
{
	pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
	if (pgd)
		pgd_ctor(pgd);
	return pgd;
}

void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
	pgd_dtor(pgd);
	kmem_cache_free(pgd_cache, pgd);
}


#define L2_USER_PGTABLE_PAGES (1 << L2_USER_PGTABLE_ORDER)

struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
	gfp_t flags = GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO|__GFP_COMP;
	struct page *p;

#ifdef CONFIG_HIGHPTE
	flags |= __GFP_HIGHMEM;
#endif

	p = alloc_pages(flags, L2_USER_PGTABLE_ORDER);
	if (p == NULL)
		return NULL;

	pgtable_page_ctor(p);
	return p;
}

/*
 * Free page immediately (used in __pte_alloc if we raced with another
 * process).  We have to correct whatever pte_alloc_one() did before
 * returning the pages to the allocator.
 */
void pte_free(struct mm_struct *mm, struct page *p)
{
	pgtable_page_dtor(p);
	__free_pages(p, L2_USER_PGTABLE_ORDER);
}

void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
		    unsigned long address)
{
	int i;

	pgtable_page_dtor(pte);
	for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i)
		tlb_remove_page(tlb, pte + i);
}

#ifndef __tilegx__

/*
 * FIXME: needs to be atomic vs hypervisor writes.  For now we make the
 * window of vulnerability a bit smaller by doing an unlocked 8-bit update.
 */
int ptep_test_and_clear_young(struct vm_area_struct *vma,
			      unsigned long addr, pte_t *ptep)
{
#if HV_PTE_INDEX_ACCESSED < 8 || HV_PTE_INDEX_ACCESSED >= 16
# error Code assumes HV_PTE "accessed" bit in second byte
#endif
	u8 *tmp = (u8 *)ptep;
	u8 second_byte = tmp[1];
	if (!(second_byte & (1 << (HV_PTE_INDEX_ACCESSED - 8))))
		return 0;
	tmp[1] = second_byte & ~(1 << (HV_PTE_INDEX_ACCESSED - 8));
	return 1;
}

/*
 * This implementation is atomic vs hypervisor writes, since the hypervisor
 * always writes the low word (where "accessed" and "dirty" are) and this
 * routine only writes the high word.
 */
void ptep_set_wrprotect(struct mm_struct *mm,
			unsigned long addr, pte_t *ptep)
{
#if HV_PTE_INDEX_WRITABLE < 32
# error Code assumes HV_PTE "writable" bit in high word
#endif
	u32 *tmp = (u32 *)ptep;
	tmp[1] = tmp[1] & ~(1 << (HV_PTE_INDEX_WRITABLE - 32));
}

#endif

pte_t *virt_to_pte(struct mm_struct* mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;

	if (pgd_addr_invalid(addr))
		return NULL;

	pgd = mm ? pgd_offset(mm, addr) : swapper_pg_dir + pgd_index(addr);
	pud = pud_offset(pgd, addr);
	if (!pud_present(*pud))
		return NULL;
	pmd = pmd_offset(pud, addr);
	if (pmd_huge_page(*pmd))
		return (pte_t *)pmd;
	if (!pmd_present(*pmd))
		return NULL;
	return pte_offset_kernel(pmd, addr);
}

pgprot_t set_remote_cache_cpu(pgprot_t prot, int cpu)
{
	unsigned int width = smp_width;
	int x = cpu % width;
	int y = cpu / width;
	BUG_ON(y >= smp_height);
	BUG_ON(hv_pte_get_mode(prot) != HV_PTE_MODE_CACHE_TILE_L3);
	BUG_ON(cpu < 0 || cpu >= NR_CPUS);
	BUG_ON(!cpu_is_valid_lotar(cpu));
	return hv_pte_set_lotar(prot, HV_XY_TO_LOTAR(x, y));
}

int get_remote_cache_cpu(pgprot_t prot)
{
	HV_LOTAR lotar = hv_pte_get_lotar(prot);
	int x = HV_LOTAR_X(lotar);
	int y = HV_LOTAR_Y(lotar);
	BUG_ON(hv_pte_get_mode(prot) != HV_PTE_MODE_CACHE_TILE_L3);
	return x + y * smp_width;
}

void set_pte_order(pte_t *ptep, pte_t pte, int order)
{
	unsigned long pfn = pte_pfn(pte);
	struct page *page = pfn_to_page(pfn);

	/* Update the home of a PTE if necessary */
	pte = pte_set_home(pte, page_home(page));

#ifdef __tilegx__
	*ptep = pte;
#else
	/*
	 * When setting a PTE, write the high bits first, then write
	 * the low bits.  This sets the "present" bit only after the
	 * other bits are in place.  If a particular PTE update
	 * involves transitioning from one valid PTE to another, it
	 * may be necessary to call set_pte_order() more than once,
	 * transitioning via a suitable intermediate state.
	 * Note that this sequence also means that if we are transitioning
	 * from any migrating PTE to a non-migrating one, we will not
	 * see a half-updated PTE with the migrating bit off.
	 */
#if HV_PTE_INDEX_PRESENT >= 32 || HV_PTE_INDEX_MIGRATING >= 32
# error Must write the present and migrating bits last
#endif
	((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32);
	barrier();
	((u32 *)ptep)[0] = (u32)(pte_val(pte));
#endif
}

/* Can this mm load a PTE with cached_priority set? */
static inline int mm_is_priority_cached(struct mm_struct *mm)
{
	return mm->context.priority_cached;
}

/*
 * Add a priority mapping to an mm_context and
 * notify the hypervisor if this is the first one.
 */
void start_mm_caching(struct mm_struct *mm)
{
	if (!mm_is_priority_cached(mm)) {
		mm->context.priority_cached = -1U;
		hv_set_caching(-1U);
	}
}

/*
 * Validate and return the priority_cached flag.  We know if it's zero
 * that we don't need to scan, since we immediately set it non-zero
 * when we first consider a MAP_CACHE_PRIORITY mapping.
 *
 * We only _try_ to acquire the mmap_sem semaphore; if we can't acquire it,
 * since we're in an interrupt context (servicing switch_mm) we don't
 * worry about it and don't unset the "priority_cached" field.
 * Presumably we'll come back later and have more luck and clear
 * the value then; for now we'll just keep the cache marked for priority.
 */
static unsigned int update_priority_cached(struct mm_struct *mm)
{
	if (mm->context.priority_cached && down_write_trylock(&mm->mmap_sem)) {
		struct vm_area_struct *vm;
		for (vm = mm->mmap; vm; vm = vm->vm_next) {
			if (hv_pte_get_cached_priority(vm->vm_page_prot))
				break;
		}
		if (vm == NULL)
			mm->context.priority_cached = 0;
		up_write(&mm->mmap_sem);
	}
	return mm->context.priority_cached;
}

/* Set caching correctly for an mm that we are switching to. */
void check_mm_caching(struct mm_struct *prev, struct mm_struct *next)
{
	if (!mm_is_priority_cached(next)) {
		/*
		 * If the new mm doesn't use priority caching, just see if we
		 * need the hv_set_caching(), or can assume it's already zero.
		 */
		if (mm_is_priority_cached(prev))
			hv_set_caching(0);
	} else {
		hv_set_caching(update_priority_cached(next));
	}
}

#if CHIP_HAS_MMIO()

/* Map an arbitrary MMIO address, homed according to pgprot, into VA space. */
void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
			   pgprot_t home)
{
	void *addr;
	struct vm_struct *area;
	unsigned long offset, last_addr;
	pgprot_t pgprot;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;
	if (!size || last_addr < phys_addr)
		return NULL;

	/* Create a read/write, MMIO VA mapping homed at the requested shim. */
	pgprot = PAGE_KERNEL;
	pgprot = hv_pte_set_mode(pgprot, HV_PTE_MODE_MMIO);
	pgprot = hv_pte_set_lotar(pgprot, hv_pte_get_lotar(home));

	/*
	 * Mappings have to be page-aligned
	 */
	offset = phys_addr & ~PAGE_MASK;
	phys_addr &= PAGE_MASK;
	size = PAGE_ALIGN(last_addr+1) - phys_addr;

	/*
	 * Ok, go for it..
	 */
	area = get_vm_area(size, VM_IOREMAP /* | other flags? */);
	if (!area)
		return NULL;
	area->phys_addr = phys_addr;
	addr = area->addr;
	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
			       phys_addr, pgprot)) {
		remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
		return NULL;
	}
	return (__force void __iomem *) (offset + (char *)addr);
}
EXPORT_SYMBOL(ioremap_prot);

/* Map a PCI MMIO bus address into VA space. */
void __iomem *ioremap(resource_size_t phys_addr, unsigned long size)
{
	panic("ioremap for PCI MMIO is not supported");
}
EXPORT_SYMBOL(ioremap);

/* Unmap an MMIO VA mapping. */
void iounmap(volatile void __iomem *addr_in)
{
	volatile void __iomem *addr = (volatile void __iomem *)
		(PAGE_MASK & (unsigned long __force)addr_in);
#if 1
	vunmap((void * __force)addr);
#else
	/* x86 uses this complicated flow instead of vunmap().  Is
	 * there any particular reason we should do the same? */
	struct vm_struct *p, *o;

	/* Use the vm area unlocked, assuming the caller
	   ensures there isn't another iounmap for the same address
	   in parallel. Reuse of the virtual address is prevented by
	   leaving it in the global lists until we're done with it.
	   cpa takes care of the direct mappings. */
	read_lock(&vmlist_lock);
	for (p = vmlist; p; p = p->next) {
		if (p->addr == addr)
			break;
	}
	read_unlock(&vmlist_lock);

	if (!p) {
		pr_err("iounmap: bad address %p\n", addr);
		dump_stack();
		return;
	}

	/* Finally remove it */
	o = remove_vm_area((void *)addr);
	BUG_ON(p != o || o == NULL);
	kfree(p);
#endif
}
EXPORT_SYMBOL(iounmap);

#endif /* CHIP_HAS_MMIO() */