aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/mm/mmu_context_iommu.c
blob: da6a2168ae9e1dd64d755344e77463338c0a5906 (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
/*
 *  IOMMU helpers in MMU context.
 *
 *  Copyright (C) 2015 IBM Corp. <aik@ozlabs.ru>
 *
 *  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; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <asm/mmu_context.h>

static DEFINE_MUTEX(mem_list_mutex);

struct mm_iommu_table_group_mem_t {
	struct list_head next;
	struct rcu_head rcu;
	unsigned long used;
	atomic64_t mapped;
	u64 ua;			/* userspace address */
	u64 entries;		/* number of entries in hpas[] */
	u64 *hpas;		/* vmalloc'ed */
};

static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
		unsigned long npages, bool incr)
{
	long ret = 0, locked, lock_limit;

	if (!npages)
		return 0;

	down_write(&mm->mmap_sem);

	if (incr) {
		locked = mm->locked_vm + npages;
		lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
		if (locked > lock_limit && !capable(CAP_IPC_LOCK))
			ret = -ENOMEM;
		else
			mm->locked_vm += npages;
	} else {
		if (WARN_ON_ONCE(npages > mm->locked_vm))
			npages = mm->locked_vm;
		mm->locked_vm -= npages;
	}

	pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
			current->pid,
			incr ? '+' : '-',
			npages << PAGE_SHIFT,
			mm->locked_vm << PAGE_SHIFT,
			rlimit(RLIMIT_MEMLOCK));
	up_write(&mm->mmap_sem);

	return ret;
}

bool mm_iommu_preregistered(void)
{
	if (!current || !current->mm)
		return false;

	return !list_empty(&current->mm->context.iommu_group_mem_list);
}
EXPORT_SYMBOL_GPL(mm_iommu_preregistered);

long mm_iommu_get(unsigned long ua, unsigned long entries,
		struct mm_iommu_table_group_mem_t **pmem)
{
	struct mm_iommu_table_group_mem_t *mem;
	long i, j, ret = 0, locked_entries = 0;
	struct page *page = NULL;

	if (!current || !current->mm)
		return -ESRCH; /* process exited */

	mutex_lock(&mem_list_mutex);

	list_for_each_entry_rcu(mem, &current->mm->context.iommu_group_mem_list,
			next) {
		if ((mem->ua == ua) && (mem->entries == entries)) {
			++mem->used;
			*pmem = mem;
			goto unlock_exit;
		}

		/* Overlap? */
		if ((mem->ua < (ua + (entries << PAGE_SHIFT))) &&
				(ua < (mem->ua +
				       (mem->entries << PAGE_SHIFT)))) {
			ret = -EINVAL;
			goto unlock_exit;
		}

	}

	ret = mm_iommu_adjust_locked_vm(current->mm, entries, true);
	if (ret)
		goto unlock_exit;

	locked_entries = entries;

	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
	if (!mem) {
		ret = -ENOMEM;
		goto unlock_exit;
	}

	mem->hpas = vzalloc(entries * sizeof(mem->hpas[0]));
	if (!mem->hpas) {
		kfree(mem);
		ret = -ENOMEM;
		goto unlock_exit;
	}

	for (i = 0; i < entries; ++i) {
		if (1 != get_user_pages_fast(ua + (i << PAGE_SHIFT),
					1/* pages */, 1/* iswrite */, &page)) {
			for (j = 0; j < i; ++j)
				put_page(pfn_to_page(
						mem->hpas[j] >> PAGE_SHIFT));
			vfree(mem->hpas);
			kfree(mem);
			ret = -EFAULT;
			goto unlock_exit;
		}

		mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT;
	}

	atomic64_set(&mem->mapped, 1);
	mem->used = 1;
	mem->ua = ua;
	mem->entries = entries;
	*pmem = mem;

	list_add_rcu(&mem->next, &current->mm->context.iommu_group_mem_list);

unlock_exit:
	if (locked_entries && ret)
		mm_iommu_adjust_locked_vm(current->mm, locked_entries, false);

	mutex_unlock(&mem_list_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_get);

static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
{
	long i;
	struct page *page = NULL;

	for (i = 0; i < mem->entries; ++i) {
		if (!mem->hpas[i])
			continue;

		page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT);
		if (!page)
			continue;

		put_page(page);
		mem->hpas[i] = 0;
	}
}

static void mm_iommu_do_free(struct mm_iommu_table_group_mem_t *mem)
{

	mm_iommu_unpin(mem);
	vfree(mem->hpas);
	kfree(mem);
}

static void mm_iommu_free(struct rcu_head *head)
{
	struct mm_iommu_table_group_mem_t *mem = container_of(head,
			struct mm_iommu_table_group_mem_t, rcu);

	mm_iommu_do_free(mem);
}

static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem)
{
	list_del_rcu(&mem->next);
	mm_iommu_adjust_locked_vm(current->mm, mem->entries, false);
	call_rcu(&mem->rcu, mm_iommu_free);
}

long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
{
	long ret = 0;

	if (!current || !current->mm)
		return -ESRCH; /* process exited */

	mutex_lock(&mem_list_mutex);

	if (mem->used == 0) {
		ret = -ENOENT;
		goto unlock_exit;
	}

	--mem->used;
	/* There are still users, exit */
	if (mem->used)
		goto unlock_exit;

	/* Are there still mappings? */
	if (atomic_cmpxchg(&mem->mapped, 1, 0) != 1) {
		++mem->used;
		ret = -EBUSY;
		goto unlock_exit;
	}

	/* @mapped became 0 so now mappings are disabled, release the region */
	mm_iommu_release(mem);

unlock_exit:
	mutex_unlock(&mem_list_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_put);

struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
		unsigned long size)
{
	struct mm_iommu_table_group_mem_t *mem, *ret = NULL;

	list_for_each_entry_rcu(mem,
			&current->mm->context.iommu_group_mem_list,
			next) {
		if ((mem->ua <= ua) &&
				(ua + size <= mem->ua +
				 (mem->entries << PAGE_SHIFT))) {
			ret = mem;
			break;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_lookup);

struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
		unsigned long entries)
{
	struct mm_iommu_table_group_mem_t *mem, *ret = NULL;

	list_for_each_entry_rcu(mem,
			&current->mm->context.iommu_group_mem_list,
			next) {
		if ((mem->ua == ua) && (mem->entries == entries)) {
			ret = mem;
			break;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(mm_iommu_find);

long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
		unsigned long ua, unsigned long *hpa)
{
	const long entry = (ua - mem->ua) >> PAGE_SHIFT;
	u64 *va = &mem->hpas[entry];

	if (entry >= mem->entries)
		return -EFAULT;

	*hpa = *va | (ua & ~PAGE_MASK);

	return 0;
}
EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);

long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem)
{
	if (atomic64_inc_not_zero(&mem->mapped))
		return 0;

	/* Last mm_iommu_put() has been called, no more mappings allowed() */
	return -ENXIO;
}
EXPORT_SYMBOL_GPL(mm_iommu_mapped_inc);

void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem)
{
	atomic64_add_unless(&mem->mapped, -1, 1);
}
EXPORT_SYMBOL_GPL(mm_iommu_mapped_dec);

void mm_iommu_init(mm_context_t *ctx)
{
	INIT_LIST_HEAD_RCU(&ctx->iommu_group_mem_list);
}

void mm_iommu_cleanup(mm_context_t *ctx)
{
	struct mm_iommu_table_group_mem_t *mem, *tmp;

	list_for_each_entry_safe(mem, tmp, &ctx->iommu_group_mem_list, next) {
		list_del_rcu(&mem->next);
		mm_iommu_do_free(mem);
	}
}