summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/ptdump/hashpagetable.c
blob: ad6df9a2e7c8ca0a52d5d9d727a5f4e047f24629 (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
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2016, Rashmica Gupta, IBM Corp.
 *
 * This traverses the kernel virtual memory and dumps the pages that are in
 * the hash pagetable, along with their flags to
 * /sys/kernel/debug/kernel_hash_pagetable.
 *
 * If radix is enabled then there is no hash page table and so no debugfs file
 * is generated.
 */
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/const.h>
#include <asm/page.h>
#include <asm/plpar_wrappers.h>
#include <linux/memblock.h>
#include <asm/firmware.h>
#include <asm/pgalloc.h>

struct pg_state {
	struct seq_file *seq;
	const struct addr_marker *marker;
	unsigned long start_address;
	unsigned int level;
	u64 current_flags;
};

struct addr_marker {
	unsigned long start_address;
	const char *name;
};

static struct addr_marker address_markers[] = {
	{ 0,	"Start of kernel VM" },
	{ 0,	"vmalloc() Area" },
	{ 0,	"vmalloc() End" },
	{ 0,	"isa I/O start" },
	{ 0,	"isa I/O end" },
	{ 0,	"phb I/O start" },
	{ 0,	"phb I/O end" },
	{ 0,	"I/O remap start" },
	{ 0,	"I/O remap end" },
	{ 0,	"vmemmap start" },
	{ -1,	NULL },
};

struct flag_info {
	u64		mask;
	u64		val;
	const char	*set;
	const char	*clear;
	bool		is_val;
	int		shift;
};

static const struct flag_info v_flag_array[] = {
	{
		.mask   = SLB_VSID_B,
		.val    = SLB_VSID_B_256M,
		.set    = "ssize: 256M",
		.clear  = "ssize: 1T  ",
	}, {
		.mask	= HPTE_V_SECONDARY,
		.val	= HPTE_V_SECONDARY,
		.set	= "secondary",
		.clear	= "primary  ",
	}, {
		.mask	= HPTE_V_VALID,
		.val	= HPTE_V_VALID,
		.set	= "valid  ",
		.clear	= "invalid",
	}, {
		.mask	= HPTE_V_BOLTED,
		.val	= HPTE_V_BOLTED,
		.set	= "bolted",
		.clear	= "",
	}
};

static const struct flag_info r_flag_array[] = {
	{
		.mask	= HPTE_R_PP0 | HPTE_R_PP,
		.val	= PP_RWXX,
		.set	= "prot:RW--",
	}, {
		.mask	= HPTE_R_PP0 | HPTE_R_PP,
		.val	= PP_RWRX,
		.set	= "prot:RWR-",
	}, {
		.mask	= HPTE_R_PP0 | HPTE_R_PP,
		.val	= PP_RWRW,
		.set	= "prot:RWRW",
	}, {
		.mask	= HPTE_R_PP0 | HPTE_R_PP,
		.val	= PP_RXRX,
		.set	= "prot:R-R-",
	}, {
		.mask	= HPTE_R_PP0 | HPTE_R_PP,
		.val	= PP_RXXX,
		.set	= "prot:R---",
	}, {
		.mask	= HPTE_R_KEY_HI | HPTE_R_KEY_LO,
		.val	= HPTE_R_KEY_HI | HPTE_R_KEY_LO,
		.set	= "key",
		.clear	= "",
		.is_val = true,
	}, {
		.mask	= HPTE_R_R,
		.val	= HPTE_R_R,
		.set	= "ref",
		.clear	= "   ",
	}, {
		.mask	= HPTE_R_C,
		.val	= HPTE_R_C,
		.set	= "changed",
		.clear	= "       ",
	}, {
		.mask	= HPTE_R_N,
		.val	= HPTE_R_N,
		.set	= "no execute",
	}, {
		.mask	= HPTE_R_WIMG,
		.val	= HPTE_R_W,
		.set	= "writethru",
	}, {
		.mask	= HPTE_R_WIMG,
		.val	= HPTE_R_I,
		.set	= "no cache",
	}, {
		.mask	= HPTE_R_WIMG,
		.val	= HPTE_R_G,
		.set	= "guarded",
	}
};

static int calculate_pagesize(struct pg_state *st, int ps, char s[])
{
	static const char units[] = "BKMGTPE";
	const char *unit = units;

	while (ps > 9 && unit[1]) {
		ps -= 10;
		unit++;
	}
	seq_printf(st->seq, "  %s_ps: %i%c\t", s, 1<<ps, *unit);
	return ps;
}

static void dump_flag_info(struct pg_state *st, const struct flag_info
		*flag, u64 pte, int num)
{
	unsigned int i;

	for (i = 0; i < num; i++, flag++) {
		const char *s = NULL;
		u64 val;

		/* flag not defined so don't check it */
		if (flag->mask == 0)
			continue;
		/* Some 'flags' are actually values */
		if (flag->is_val) {
			val = pte & flag->val;
			if (flag->shift)
				val = val >> flag->shift;
			seq_printf(st->seq, "  %s:%llx", flag->set, val);
		} else {
			if ((pte & flag->mask) == flag->val)
				s = flag->set;
			else
				s = flag->clear;
			if (s)
				seq_printf(st->seq, "  %s", s);
		}
	}
}

static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
		unsigned long rpn, int bps, int aps, unsigned long lp)
{
	int aps_index;

	while (ea >= st->marker[1].start_address) {
		st->marker++;
		seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
	}
	seq_printf(st->seq, "0x%lx:\t", ea);
	seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
	dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
	seq_printf(st->seq, "  rpn: %lx\t", rpn);
	dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));

	calculate_pagesize(st, bps, "base");
	aps_index = calculate_pagesize(st, aps, "actual");
	if (aps_index != 2)
		seq_printf(st->seq, "LP enc: %lx", lp);
	seq_putc(st->seq, '\n');
}


static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
		*r)
{
	struct hash_pte *hptep;
	unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
	int i, ssize = mmu_kernel_ssize;
	unsigned long shift = mmu_psize_defs[psize].shift;

	/* calculate hash */
	vsid = get_kernel_vsid(ea, ssize);
	vpn  = hpt_vpn(ea, vsid, ssize);
	hash = hpt_hash(vpn, shift, ssize);
	want_v = hpte_encode_avpn(vpn, psize, ssize);

	/* to check in the secondary hash table, we invert the hash */
	if (!primary)
		hash = ~hash;
	hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
	for (i = 0; i < HPTES_PER_GROUP; i++) {
		hptep = htab_address + hpte_group;
		hpte_v = be64_to_cpu(hptep->v);

		if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
			/* HPTE matches */
			*v = be64_to_cpu(hptep->v);
			*r = be64_to_cpu(hptep->r);
			return 0;
		}
		++hpte_group;
	}
	return -1;
}

static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
{
	struct hash_pte ptes[4];
	unsigned long vsid, vpn, hash, hpte_group, want_v;
	int i, j, ssize = mmu_kernel_ssize;
	long lpar_rc = 0;
	unsigned long shift = mmu_psize_defs[psize].shift;

	/* calculate hash */
	vsid = get_kernel_vsid(ea, ssize);
	vpn  = hpt_vpn(ea, vsid, ssize);
	hash = hpt_hash(vpn, shift, ssize);
	want_v = hpte_encode_avpn(vpn, psize, ssize);

	/* to check in the secondary hash table, we invert the hash */
	if (!primary)
		hash = ~hash;
	hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
	/* see if we can find an entry in the hpte with this hash */
	for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
		lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);

		if (lpar_rc)
			continue;
		for (j = 0; j < 4; j++) {
			if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
					(ptes[j].v & HPTE_V_VALID)) {
				/* HPTE matches */
				*v = ptes[j].v;
				*r = ptes[j].r;
				return 0;
			}
		}
	}
	return -1;
}

static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
		unsigned long *lp_bits)
{
	struct mmu_psize_def entry;
	unsigned long arpn, mask, lp;
	int penc = -2, idx = 0, shift;

	/*.
	 * The LP field has 8 bits. Depending on the actual page size, some of
	 * these bits are concatenated with the APRN to get the RPN. The rest
	 * of the bits in the LP field is the LP value and is an encoding for
	 * the base page size and the actual page size.
	 *
	 *  -	find the mmu entry for our base page size
	 *  -	go through all page encodings and use the associated mask to
	 *	find an encoding that matches our encoding in the LP field.
	 */
	arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
	lp = arpn & 0xff;

	entry = mmu_psize_defs[bps];
	while (idx < MMU_PAGE_COUNT) {
		penc = entry.penc[idx];
		if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
			shift = mmu_psize_defs[idx].shift -  HPTE_R_RPN_SHIFT;
			mask = (0x1 << (shift)) - 1;
			if ((lp & mask) == penc) {
				*aps = mmu_psize_to_shift(idx);
				*lp_bits = lp & mask;
				*rpn = arpn >> shift;
				return;
			}
		}
		idx++;
	}
}

static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
			  u64 *r)
{
	if (IS_ENABLED(CONFIG_PPC_PSERIES) && firmware_has_feature(FW_FEATURE_LPAR))
		return pseries_find(ea, psize, primary, v, r);

	return native_find(ea, psize, primary, v, r);
}

static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
{
	unsigned long slot;
	u64 v  = 0, r = 0;
	unsigned long rpn, lp_bits;
	int base_psize = 0, actual_psize = 0;

	if (ea < PAGE_OFFSET)
		return -1;

	/* Look in primary table */
	slot = base_hpte_find(ea, psize, true, &v, &r);

	/* Look in secondary table */
	if (slot == -1)
		slot = base_hpte_find(ea, psize, false, &v, &r);

	/* No entry found */
	if (slot == -1)
		return -1;

	/*
	 * We found an entry in the hash page table:
	 *  - check that this has the same base page
	 *  - find the actual page size
	 *  - find the RPN
	 */
	base_psize = mmu_psize_to_shift(psize);

	if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
		decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
	} else {
		/* 4K actual page size */
		actual_psize = 12;
		rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
		/* In this case there are no LP bits */
		lp_bits = -1;
	}
	/*
	 * We didn't find a matching encoding, so the PTE we found isn't for
	 * this address.
	 */
	if (actual_psize == -1)
		return -1;

	dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
	return 0;
}

static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
{
	pte_t *pte = pte_offset_kernel(pmd, 0);
	unsigned long addr, pteval, psize;
	int i, status;

	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
		addr = start + i * PAGE_SIZE;
		pteval = pte_val(*pte);

		if (addr < VMALLOC_END)
			psize = mmu_vmalloc_psize;
		else
			psize = mmu_io_psize;

		/* check for secret 4K mappings */
		if (IS_ENABLED(CONFIG_PPC_64K_PAGES) &&
		    ((pteval & H_PAGE_COMBO) == H_PAGE_COMBO ||
		     (pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
			psize = mmu_io_psize;

		/* check for hashpte */
		status = hpte_find(st, addr, psize);

		if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
				&& (status != -1)) {
		/* found a hpte that is not in the linux page tables */
			seq_printf(st->seq, "page probably bolted before linux"
				" pagetables were set: addr:%lx, pteval:%lx\n",
				addr, pteval);
		}
	}
}

static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
{
	pmd_t *pmd = pmd_offset(pud, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
		addr = start + i * PMD_SIZE;
		if (!pmd_none(*pmd))
			/* pmd exists */
			walk_pte(st, pmd, addr);
	}
}

static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
{
	pud_t *pud = pud_offset(p4d, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
		addr = start + i * PUD_SIZE;
		if (!pud_none(*pud))
			/* pud exists */
			walk_pmd(st, pud, addr);
	}
}

static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
{
	p4d_t *p4d = p4d_offset(pgd, 0);
	unsigned long addr;
	unsigned int i;

	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
		addr = start + i * P4D_SIZE;
		if (!p4d_none(*p4d))
			/* p4d exists */
			walk_pud(st, p4d, addr);
	}
}

static void walk_pagetables(struct pg_state *st)
{
	pgd_t *pgd = pgd_offset_k(0UL);
	unsigned int i;
	unsigned long addr;

	/*
	 * Traverse the linux pagetable structure and dump pages that are in
	 * the hash pagetable.
	 */
	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
		addr = KERN_VIRT_START + i * PGDIR_SIZE;
		if (!pgd_none(*pgd))
			/* pgd exists */
			walk_p4d(st, pgd, addr);
	}
}


static void walk_linearmapping(struct pg_state *st)
{
	unsigned long addr;

	/*
	 * Traverse the linear mapping section of virtual memory and dump pages
	 * that are in the hash pagetable.
	 */
	unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;

	for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
			memblock_end_of_DRAM(); addr += psize)
		hpte_find(st, addr, mmu_linear_psize);
}

static void walk_vmemmap(struct pg_state *st)
{
	struct vmemmap_backing *ptr = vmemmap_list;

	if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
		return;
	/*
	 * Traverse the vmemmaped memory and dump pages that are in the hash
	 * pagetable.
	 */
	while (ptr->list) {
		hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
		ptr = ptr->list;
	}
	seq_puts(st->seq, "---[ vmemmap end ]---\n");
}

static void populate_markers(void)
{
	address_markers[0].start_address = PAGE_OFFSET;
	address_markers[1].start_address = VMALLOC_START;
	address_markers[2].start_address = VMALLOC_END;
	address_markers[3].start_address = ISA_IO_BASE;
	address_markers[4].start_address = ISA_IO_END;
	address_markers[5].start_address = PHB_IO_BASE;
	address_markers[6].start_address = PHB_IO_END;
	address_markers[7].start_address = IOREMAP_BASE;
	address_markers[8].start_address = IOREMAP_END;
	address_markers[9].start_address =  H_VMEMMAP_START;
}

static int ptdump_show(struct seq_file *m, void *v)
{
	struct pg_state st = {
		.seq = m,
		.start_address = PAGE_OFFSET,
		.marker = address_markers,
	};
	/*
	 * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
	 * dump pages that are in the hash pagetable.
	 */
	walk_linearmapping(&st);
	walk_pagetables(&st);
	walk_vmemmap(&st);
	return 0;
}

static int ptdump_open(struct inode *inode, struct file *file)
{
	return single_open(file, ptdump_show, NULL);
}

static const struct file_operations ptdump_fops = {
	.open		= ptdump_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int ptdump_init(void)
{
	if (!radix_enabled()) {
		populate_markers();
		debugfs_create_file("kernel_hash_pagetable", 0400, NULL, NULL,
				    &ptdump_fops);
	}
	return 0;
}
device_initcall(ptdump_init);