drivers/android/binder_alloc_selftest.c

   1 /* binder_alloc_selftest.c
   2  *
   3  * Android IPC Subsystem
   4  *
   5  * Copyright (C) 2017 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/mm_types.h>
  21 #include <linux/err.h>
  22 #include "binder_alloc.h"
  23
  24 #define BUFFER_NUM 5
  25 #define BUFFER_MIN_SIZE (PAGE_SIZE / 8)
  26
  27 static bool binder_selftest_run = true;
  28 static int binder_selftest_failures;
  29 static DEFINE_MUTEX(binder_selftest_lock);
  30
  31 /**
  32  * enum buf_end_align_type - Page alignment of a buffer
  33  * end with regard to the end of the previous buffer.
  34  *
  35  * In the pictures below, buf2 refers to the buffer we
  36  * are aligning. buf1 refers to previous buffer by addr.
  37  * Symbol [ means the start of a buffer, ] means the end
  38  * of a buffer, and | means page boundaries.
  39  */
  40 enum buf_end_align_type {
  41         /**
  42          * @SAME_PAGE_UNALIGNED: The end of this buffer is on
  43          * the same page as the end of the previous buffer and
  44          * is not page aligned. Examples:
  45          * buf1 ][ buf2 ][ ...
  46          * buf1 ]|[ buf2 ][ ...
  47          */
  48         SAME_PAGE_UNALIGNED = 0,
  49         /**
  50          * @SAME_PAGE_ALIGNED: When the end of the previous buffer
  51          * is not page aligned, the end of this buffer is on the
  52          * same page as the end of the previous buffer and is page
  53          * aligned. When the previous buffer is page aligned, the
  54          * end of this buffer is aligned to the next page boundary.
  55          * Examples:
  56          * buf1 ][ buf2 ]| ...
  57          * buf1 ]|[ buf2 ]| ...
  58          */
  59         SAME_PAGE_ALIGNED,
  60         /**
  61          * @NEXT_PAGE_UNALIGNED: The end of this buffer is on
  62          * the page next to the end of the previous buffer and
  63          * is not page aligned. Examples:
  64          * buf1 ][ buf2 | buf2 ][ ...
  65          * buf1 ]|[ buf2 | buf2 ][ ...
  66          */
  67         NEXT_PAGE_UNALIGNED,
  68         /**
  69          * @NEXT_PAGE_ALIGNED: The end of this buffer is on
  70          * the page next to the end of the previous buffer and
  71          * is page aligned. Examples:
  72          * buf1 ][ buf2 | buf2 ]| ...
  73          * buf1 ]|[ buf2 | buf2 ]| ...
  74          */
  75         NEXT_PAGE_ALIGNED,
  76         /**
  77          * @NEXT_NEXT_UNALIGNED: The end of this buffer is on
  78          * the page that follows the page after the end of the
  79          * previous buffer and is not page aligned. Examples:
  80          * buf1 ][ buf2 | buf2 | buf2 ][ ...
  81          * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
  82          */
  83         NEXT_NEXT_UNALIGNED,
  84         LOOP_END,
  85 };
  86
  87 static void pr_err_size_seq(size_t *sizes, int *seq)
  88 {
  89         int i;
  90
  91         pr_err("alloc sizes: ");
  92         for (i = 0; i < BUFFER_NUM; i++)
  93                 pr_cont("[%zu]", sizes[i]);
  94         pr_cont("\n");
  95         pr_err("free seq: ");
  96         for (i = 0; i < BUFFER_NUM; i++)
  97                 pr_cont("[%d]", seq[i]);
  98         pr_cont("\n");
  99 }
 100
 101 static bool check_buffer_pages_allocated(struct binder_alloc *alloc,
 102                                          struct binder_buffer *buffer,
 103                                          size_t size)
 104 {
 105         void *page_addr, *end;
 106         int page_index;
 107
 108         end = (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 109         page_addr = buffer->data;
 110         for (; page_addr < end; page_addr += PAGE_SIZE) {
 111                 page_index = (page_addr - alloc->buffer) / PAGE_SIZE;
 112                 if (!alloc->pages[page_index]) {
 113                         pr_err("incorrect alloc state at page index %d\n",
 114                                page_index);
 115                         return false;
 116                 }
 117         }
 118         return true;
 119 }
 120
 121 static void binder_selftest_alloc_buf(struct binder_alloc *alloc,
 122                                       struct binder_buffer *buffers[],
 123                                       size_t *sizes, int *seq)
 124 {
 125         int i;
 126
 127         for (i = 0; i < BUFFER_NUM; i++) {
 128                 buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
 129                 if (IS_ERR(buffers[i]) ||
 130                     !check_buffer_pages_allocated(alloc, buffers[i],
 131                                                   sizes[i])) {
 132                         pr_err_size_seq(sizes, seq);
 133                         binder_selftest_failures++;
 134                 }
 135         }
 136 }
 137
 138 static void binder_selftest_free_buf(struct binder_alloc *alloc,
 139                                      struct binder_buffer *buffers[],
 140                                      size_t *sizes, int *seq)
 141 {
 142         int i;
 143
 144         for (i = 0; i < BUFFER_NUM; i++)
 145                 binder_alloc_free_buf(alloc, buffers[seq[i]]);
 146
 147         for (i = 0; i < (alloc->buffer_size / PAGE_SIZE); i++) {
 148                 if ((!alloc->pages[i]) == (i == 0)) {
 149                         pr_err("incorrect free state at page index %d\n", i);
 150                         binder_selftest_failures++;
 151                 }
 152         }
 153 }
 154
 155 static void binder_selftest_alloc_free(struct binder_alloc *alloc,
 156                                        size_t *sizes, int *seq)
 157 {
 158         struct binder_buffer *buffers[BUFFER_NUM];
 159
 160         binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
 161         binder_selftest_free_buf(alloc, buffers, sizes, seq);
 162 }
 163
 164 static bool is_dup(int *seq, int index, int val)
 165 {
 166         int i;
 167
 168         for (i = 0; i < index; i++) {
 169                 if (seq[i] == val)
 170                         return true;
 171         }
 172         return false;
 173 }
 174
 175 /* Generate BUFFER_NUM factorial free orders. */
 176 static void binder_selftest_free_seq(struct binder_alloc *alloc,
 177                                      size_t *sizes, int *seq, int index)
 178 {
 179         int i;
 180
 181         if (index == BUFFER_NUM) {
 182                 binder_selftest_alloc_free(alloc, sizes, seq);
 183                 return;
 184         }
 185         for (i = 0; i < BUFFER_NUM; i++) {
 186                 if (is_dup(seq, index, i))
 187                         continue;
 188                 seq[index] = i;
 189                 binder_selftest_free_seq(alloc, sizes, seq, index + 1);
 190         }
 191 }
 192
 193 static void binder_selftest_alloc_size(struct binder_alloc *alloc,
 194                                        size_t *end_offset)
 195 {
 196         int i;
 197         int seq[BUFFER_NUM] = {0};
 198         size_t front_sizes[BUFFER_NUM];
 199         size_t back_sizes[BUFFER_NUM];
 200         size_t last_offset, offset = 0;
 201
 202         for (i = 0; i < BUFFER_NUM; i++) {
 203                 last_offset = offset;
 204                 offset = end_offset[i];
 205                 front_sizes[i] = offset - last_offset;
 206                 back_sizes[BUFFER_NUM - i - 1] = front_sizes[i];
 207         }
 208         /*
 209          * Buffers share the first or last few pages.
 210          * Only BUFFER_NUM - 1 buffer sizes are adjustable since
 211          * we need one giant buffer before getting to the last page.
 212          */
 213         back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
 214         binder_selftest_free_seq(alloc, front_sizes, seq, 0);
 215         binder_selftest_free_seq(alloc, back_sizes, seq, 0);
 216 }
 217
 218 static void binder_selftest_alloc_offset(struct binder_alloc *alloc,
 219                                          size_t *end_offset, int index)
 220 {
 221         int align;
 222         size_t end, prev;
 223
 224         if (index == BUFFER_NUM) {
 225                 binder_selftest_alloc_size(alloc, end_offset);
 226                 return;
 227         }
 228         prev = index == 0 ? 0 : end_offset[index - 1];
 229         end = prev;
 230
 231         BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);
 232
 233         for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
 234                 if (align % 2)
 235                         end = ALIGN(end, PAGE_SIZE);
 236                 else
 237                         end += BUFFER_MIN_SIZE;
 238                 end_offset[index] = end;
 239                 binder_selftest_alloc_offset(alloc, end_offset, index + 1);
 240         }
 241 }
 242
 243 /**
 244  * binder_selftest_alloc() - Test alloc and free of buffer pages.
 245  * @alloc: Pointer to alloc struct.
 246  *
 247  * Allocate BUFFER_NUM buffers to cover all page alignment cases,
 248  * then free them in all orders possible. Check that pages are
 249  * allocated after buffer alloc and freed after freeing buffer.
 250  */
 251 void binder_selftest_alloc(struct binder_alloc *alloc)
 252 {
 253         size_t end_offset[BUFFER_NUM];
 254
 255         if (!binder_selftest_run)
 256                 return;
 257         mutex_lock(&binder_selftest_lock);
 258         if (!binder_selftest_run || !alloc->vma)
 259                 goto done;
 260         pr_info("STARTED\n");
 261         binder_selftest_alloc_offset(alloc, end_offset, 0);
 262         binder_selftest_run = false;
 263         if (binder_selftest_failures > 0)
 264                 pr_info("%d tests FAILED\n", binder_selftest_failures);
 265         else
 266                 pr_info("PASSED\n");
 267
 268 done:
 269         mutex_unlock(&binder_selftest_lock);
 270 }