summaryrefslogtreecommitdiffstats
path: root/drivers/android/binder_alloc_selftest.c
blob: 4151d9938255774be527eef25f88e5dc7397fc60 (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
// SPDX-License-Identifier: GPL-2.0-only
/* binder_alloc_selftest.c
 *
 * Android IPC Subsystem
 *
 * Copyright (C) 2017 Google, Inc.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/mm_types.h>
#include <linux/err.h>
#include "binder_alloc.h"

#define BUFFER_NUM 5
#define BUFFER_MIN_SIZE (PAGE_SIZE / 8)

static bool binder_selftest_run = true;
static int binder_selftest_failures;
static DEFINE_MUTEX(binder_selftest_lock);

/**
 * enum buf_end_align_type - Page alignment of a buffer
 * end with regard to the end of the previous buffer.
 *
 * In the pictures below, buf2 refers to the buffer we
 * are aligning. buf1 refers to previous buffer by addr.
 * Symbol [ means the start of a buffer, ] means the end
 * of a buffer, and | means page boundaries.
 */
enum buf_end_align_type {
	/**
	 * @SAME_PAGE_UNALIGNED: The end of this buffer is on
	 * the same page as the end of the previous buffer and
	 * is not page aligned. Examples:
	 * buf1 ][ buf2 ][ ...
	 * buf1 ]|[ buf2 ][ ...
	 */
	SAME_PAGE_UNALIGNED = 0,
	/**
	 * @SAME_PAGE_ALIGNED: When the end of the previous buffer
	 * is not page aligned, the end of this buffer is on the
	 * same page as the end of the previous buffer and is page
	 * aligned. When the previous buffer is page aligned, the
	 * end of this buffer is aligned to the next page boundary.
	 * Examples:
	 * buf1 ][ buf2 ]| ...
	 * buf1 ]|[ buf2 ]| ...
	 */
	SAME_PAGE_ALIGNED,
	/**
	 * @NEXT_PAGE_UNALIGNED: The end of this buffer is on
	 * the page next to the end of the previous buffer and
	 * is not page aligned. Examples:
	 * buf1 ][ buf2 | buf2 ][ ...
	 * buf1 ]|[ buf2 | buf2 ][ ...
	 */
	NEXT_PAGE_UNALIGNED,
	/**
	 * @NEXT_PAGE_ALIGNED: The end of this buffer is on
	 * the page next to the end of the previous buffer and
	 * is page aligned. Examples:
	 * buf1 ][ buf2 | buf2 ]| ...
	 * buf1 ]|[ buf2 | buf2 ]| ...
	 */
	NEXT_PAGE_ALIGNED,
	/**
	 * @NEXT_NEXT_UNALIGNED: The end of this buffer is on
	 * the page that follows the page after the end of the
	 * previous buffer and is not page aligned. Examples:
	 * buf1 ][ buf2 | buf2 | buf2 ][ ...
	 * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
	 */
	NEXT_NEXT_UNALIGNED,
	LOOP_END,
};

static void pr_err_size_seq(size_t *sizes, int *seq)
{
	int i;

	pr_err("alloc sizes: ");
	for (i = 0; i < BUFFER_NUM; i++)
		pr_cont("[%zu]", sizes[i]);
	pr_cont("\n");
	pr_err("free seq: ");
	for (i = 0; i < BUFFER_NUM; i++)
		pr_cont("[%d]", seq[i]);
	pr_cont("\n");
}

static bool check_buffer_pages_allocated(struct binder_alloc *alloc,
					 struct binder_buffer *buffer,
					 size_t size)
{
	void __user *page_addr;
	void __user *end;
	int page_index;

	end = (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size);
	page_addr = buffer->user_data;
	for (; page_addr < end; page_addr += PAGE_SIZE) {
		page_index = (page_addr - alloc->buffer) / PAGE_SIZE;
		if (!alloc->pages[page_index].page_ptr ||
		    !list_empty(&alloc->pages[page_index].lru)) {
			pr_err("expect alloc but is %s at page index %d\n",
			       alloc->pages[page_index].page_ptr ?
			       "lru" : "free", page_index);
			return false;
		}
	}
	return true;
}

static void binder_selftest_alloc_buf(struct binder_alloc *alloc,
				      struct binder_buffer *buffers[],
				      size_t *sizes, int *seq)
{
	int i;

	for (i = 0; i < BUFFER_NUM; i++) {
		buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
		if (IS_ERR(buffers[i]) ||
		    !check_buffer_pages_allocated(alloc, buffers[i],
						  sizes[i])) {
			pr_err_size_seq(sizes, seq);
			binder_selftest_failures++;
		}
	}
}

static void binder_selftest_free_buf(struct binder_alloc *alloc,
				     struct binder_buffer *buffers[],
				     size_t *sizes, int *seq, size_t end)
{
	int i;

	for (i = 0; i < BUFFER_NUM; i++)
		binder_alloc_free_buf(alloc, buffers[seq[i]]);

	for (i = 0; i < end / PAGE_SIZE; i++) {
		/**
		 * Error message on a free page can be false positive
		 * if binder shrinker ran during binder_alloc_free_buf
		 * calls above.
		 */
		if (list_empty(&alloc->pages[i].lru)) {
			pr_err_size_seq(sizes, seq);
			pr_err("expect lru but is %s at page index %d\n",
			       alloc->pages[i].page_ptr ? "alloc" : "free", i);
			binder_selftest_failures++;
		}
	}
}

static void binder_selftest_free_page(struct binder_alloc *alloc)
{
	int i;
	unsigned long count;

	while ((count = list_lru_count(&binder_alloc_lru))) {
		list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
			      NULL, count);
	}

	for (i = 0; i < (alloc->buffer_size / PAGE_SIZE); i++) {
		if (alloc->pages[i].page_ptr) {
			pr_err("expect free but is %s at page index %d\n",
			       list_empty(&alloc->pages[i].lru) ?
			       "alloc" : "lru", i);
			binder_selftest_failures++;
		}
	}
}

static void binder_selftest_alloc_free(struct binder_alloc *alloc,
				       size_t *sizes, int *seq, size_t end)
{
	struct binder_buffer *buffers[BUFFER_NUM];

	binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
	binder_selftest_free_buf(alloc, buffers, sizes, seq, end);

	/* Allocate from lru. */
	binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
	if (list_lru_count(&binder_alloc_lru))
		pr_err("lru list should be empty but is not\n");

	binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
	binder_selftest_free_page(alloc);
}

static bool is_dup(int *seq, int index, int val)
{
	int i;

	for (i = 0; i < index; i++) {
		if (seq[i] == val)
			return true;
	}
	return false;
}

/* Generate BUFFER_NUM factorial free orders. */
static void binder_selftest_free_seq(struct binder_alloc *alloc,
				     size_t *sizes, int *seq,
				     int index, size_t end)
{
	int i;

	if (index == BUFFER_NUM) {
		binder_selftest_alloc_free(alloc, sizes, seq, end);
		return;
	}
	for (i = 0; i < BUFFER_NUM; i++) {
		if (is_dup(seq, index, i))
			continue;
		seq[index] = i;
		binder_selftest_free_seq(alloc, sizes, seq, index + 1, end);
	}
}

static void binder_selftest_alloc_size(struct binder_alloc *alloc,
				       size_t *end_offset)
{
	int i;
	int seq[BUFFER_NUM] = {0};
	size_t front_sizes[BUFFER_NUM];
	size_t back_sizes[BUFFER_NUM];
	size_t last_offset, offset = 0;

	for (i = 0; i < BUFFER_NUM; i++) {
		last_offset = offset;
		offset = end_offset[i];
		front_sizes[i] = offset - last_offset;
		back_sizes[BUFFER_NUM - i - 1] = front_sizes[i];
	}
	/*
	 * Buffers share the first or last few pages.
	 * Only BUFFER_NUM - 1 buffer sizes are adjustable since
	 * we need one giant buffer before getting to the last page.
	 */
	back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
	binder_selftest_free_seq(alloc, front_sizes, seq, 0,
				 end_offset[BUFFER_NUM - 1]);
	binder_selftest_free_seq(alloc, back_sizes, seq, 0, alloc->buffer_size);
}

static void binder_selftest_alloc_offset(struct binder_alloc *alloc,
					 size_t *end_offset, int index)
{
	int align;
	size_t end, prev;

	if (index == BUFFER_NUM) {
		binder_selftest_alloc_size(alloc, end_offset);
		return;
	}
	prev = index == 0 ? 0 : end_offset[index - 1];
	end = prev;

	BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);

	for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
		if (align % 2)
			end = ALIGN(end, PAGE_SIZE);
		else
			end += BUFFER_MIN_SIZE;
		end_offset[index] = end;
		binder_selftest_alloc_offset(alloc, end_offset, index + 1);
	}
}

/**
 * binder_selftest_alloc() - Test alloc and free of buffer pages.
 * @alloc: Pointer to alloc struct.
 *
 * Allocate BUFFER_NUM buffers to cover all page alignment cases,
 * then free them in all orders possible. Check that pages are
 * correctly allocated, put onto lru when buffers are freed, and
 * are freed when binder_alloc_free_page is called.
 */
void binder_selftest_alloc(struct binder_alloc *alloc)
{
	size_t end_offset[BUFFER_NUM];

	if (!binder_selftest_run)
		return;
	mutex_lock(&binder_selftest_lock);
	if (!binder_selftest_run || !alloc->vma)
		goto done;
	pr_info("STARTED\n");
	binder_selftest_alloc_offset(alloc, end_offset, 0);
	binder_selftest_run = false;
	if (binder_selftest_failures > 0)
		pr_info("%d tests FAILED\n", binder_selftest_failures);
	else
		pr_info("PASSED\n");

done:
	mutex_unlock(&binder_selftest_lock);
}