mm/gup_test.c

   1 #include <linux/kernel.h>
   2 #include <linux/mm.h>
   3 #include <linux/slab.h>
   4 #include <linux/uaccess.h>
   5 #include <linux/ktime.h>
   6 #include <linux/debugfs.h>
   7 #include <linux/highmem.h>
   8 #include "gup_test.h"
   9
  10 static void put_back_pages(unsigned int cmd, struct page **pages,
  11                            unsigned long nr_pages, unsigned int gup_test_flags)
  12 {
  13         unsigned long i;
  14
  15         switch (cmd) {
  16         case GUP_FAST_BENCHMARK:
  17         case GUP_BASIC_TEST:
  18                 for (i = 0; i < nr_pages; i++)
  19                         put_page(pages[i]);
  20                 break;
  21
  22         case PIN_FAST_BENCHMARK:
  23         case PIN_BASIC_TEST:
  24         case PIN_LONGTERM_BENCHMARK:
  25                 unpin_user_pages(pages, nr_pages);
  26                 break;
  27         case DUMP_USER_PAGES_TEST:
  28                 if (gup_test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) {
  29                         unpin_user_pages(pages, nr_pages);
  30                 } else {
  31                         for (i = 0; i < nr_pages; i++)
  32                                 put_page(pages[i]);
  33
  34                 }
  35                 break;
  36         }
  37 }
  38
  39 static void verify_dma_pinned(unsigned int cmd, struct page **pages,
  40                               unsigned long nr_pages)
  41 {
  42         unsigned long i;
  43         struct folio *folio;
  44
  45         switch (cmd) {
  46         case PIN_FAST_BENCHMARK:
  47         case PIN_BASIC_TEST:
  48         case PIN_LONGTERM_BENCHMARK:
  49                 for (i = 0; i < nr_pages; i++) {
  50                         folio = page_folio(pages[i]);
  51
  52                         if (WARN(!folio_maybe_dma_pinned(folio),
  53                                  "pages[%lu] is NOT dma-pinned\n", i)) {
  54
  55                                 dump_page(&folio->page, "gup_test failure");
  56                                 break;
  57                         } else if (cmd == PIN_LONGTERM_BENCHMARK &&
  58                                 WARN(!folio_is_longterm_pinnable(folio),
  59                                      "pages[%lu] is NOT pinnable but pinned\n",
  60                                      i)) {
  61                                 dump_page(&folio->page, "gup_test failure");
  62                                 break;
  63                         }
  64                 }
  65                 break;
  66         }
  67 }
  68
  69 static void dump_pages_test(struct gup_test *gup, struct page **pages,
  70                             unsigned long nr_pages)
  71 {
  72         unsigned int index_to_dump;
  73         unsigned int i;
  74
  75         /*
  76          * Zero out any user-supplied page index that is out of range. Remember:
  77          * .which_pages[] contains a 1-based set of page indices.
  78          */
  79         for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {
  80                 if (gup->which_pages[i] > nr_pages) {
  81                         pr_warn("ZEROING due to out of range: .which_pages[%u]: %u\n",
  82                                 i, gup->which_pages[i]);
  83                         gup->which_pages[i] = 0;
  84                 }
  85         }
  86
  87         for (i = 0; i < GUP_TEST_MAX_PAGES_TO_DUMP; i++) {
  88                 index_to_dump = gup->which_pages[i];
  89
  90                 if (index_to_dump) {
  91                         index_to_dump--; // Decode from 1-based, to 0-based
  92                         pr_info("---- page #%u, starting from user virt addr: 0x%llx\n",
  93                                 index_to_dump, gup->addr);
  94                         dump_page(pages[index_to_dump],
  95                                   "gup_test: dump_pages() test");
  96                 }
  97         }
  98 }
  99
 100 static int __gup_test_ioctl(unsigned int cmd,
 101                 struct gup_test *gup)
 102 {
 103         ktime_t start_time, end_time;
 104         unsigned long i, nr_pages, addr, next;
 105         long nr;
 106         struct page **pages;
 107         int ret = 0;
 108         bool needs_mmap_lock =
 109                 cmd != GUP_FAST_BENCHMARK && cmd != PIN_FAST_BENCHMARK;
 110
 111         if (gup->size > ULONG_MAX)
 112                 return -EINVAL;
 113
 114         nr_pages = gup->size / PAGE_SIZE;
 115         pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
 116         if (!pages)
 117                 return -ENOMEM;
 118
 119         if (needs_mmap_lock && mmap_read_lock_killable(current->mm)) {
 120                 ret = -EINTR;
 121                 goto free_pages;
 122         }
 123
 124         i = 0;
 125         nr = gup->nr_pages_per_call;
 126         start_time = ktime_get();
 127         for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
 128                 if (nr != gup->nr_pages_per_call)
 129                         break;
 130
 131                 next = addr + nr * PAGE_SIZE;
 132                 if (next > gup->addr + gup->size) {
 133                         next = gup->addr + gup->size;
 134                         nr = (next - addr) / PAGE_SIZE;
 135                 }
 136
 137                 switch (cmd) {
 138                 case GUP_FAST_BENCHMARK:
 139                         nr = get_user_pages_fast(addr, nr, gup->gup_flags,
 140                                                  pages + i);
 141                         break;
 142                 case GUP_BASIC_TEST:
 143                         nr = get_user_pages(addr, nr, gup->gup_flags, pages + i);
 144                         break;
 145                 case PIN_FAST_BENCHMARK:
 146                         nr = pin_user_pages_fast(addr, nr, gup->gup_flags,
 147                                                  pages + i);
 148                         break;
 149                 case PIN_BASIC_TEST:
 150                         nr = pin_user_pages(addr, nr, gup->gup_flags, pages + i);
 151                         break;
 152                 case PIN_LONGTERM_BENCHMARK:
 153                         nr = pin_user_pages(addr, nr,
 154                                             gup->gup_flags | FOLL_LONGTERM,
 155                                             pages + i);
 156                         break;
 157                 case DUMP_USER_PAGES_TEST:
 158                         if (gup->test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
 159                                 nr = pin_user_pages(addr, nr, gup->gup_flags,
 160                                                     pages + i);
 161                         else
 162                                 nr = get_user_pages(addr, nr, gup->gup_flags,
 163                                                     pages + i);
 164                         break;
 165                 default:
 166                         ret = -EINVAL;
 167                         goto unlock;
 168                 }
 169
 170                 if (nr <= 0)
 171                         break;
 172                 i += nr;
 173         }
 174         end_time = ktime_get();
 175
 176         /* Shifting the meaning of nr_pages: now it is actual number pinned: */
 177         nr_pages = i;
 178
 179         gup->get_delta_usec = ktime_us_delta(end_time, start_time);
 180         gup->size = addr - gup->addr;
 181
 182         /*
 183          * Take an un-benchmark-timed moment to verify DMA pinned
 184          * state: print a warning if any non-dma-pinned pages are found:
 185          */
 186         verify_dma_pinned(cmd, pages, nr_pages);
 187
 188         if (cmd == DUMP_USER_PAGES_TEST)
 189                 dump_pages_test(gup, pages, nr_pages);
 190
 191         start_time = ktime_get();
 192
 193         put_back_pages(cmd, pages, nr_pages, gup->test_flags);
 194
 195         end_time = ktime_get();
 196         gup->put_delta_usec = ktime_us_delta(end_time, start_time);
 197
 198 unlock:
 199         if (needs_mmap_lock)
 200                 mmap_read_unlock(current->mm);
 201 free_pages:
 202         kvfree(pages);
 203         return ret;
 204 }
 205
 206 static DEFINE_MUTEX(pin_longterm_test_mutex);
 207 static struct page **pin_longterm_test_pages;
 208 static unsigned long pin_longterm_test_nr_pages;
 209
 210 static inline void pin_longterm_test_stop(void)
 211 {
 212         if (pin_longterm_test_pages) {
 213                 if (pin_longterm_test_nr_pages)
 214                         unpin_user_pages(pin_longterm_test_pages,
 215                                          pin_longterm_test_nr_pages);
 216                 kvfree(pin_longterm_test_pages);
 217                 pin_longterm_test_pages = NULL;
 218                 pin_longterm_test_nr_pages = 0;
 219         }
 220 }
 221
 222 static inline int pin_longterm_test_start(unsigned long arg)
 223 {
 224         long nr_pages, cur_pages, addr, remaining_pages;
 225         int gup_flags = FOLL_LONGTERM;
 226         struct pin_longterm_test args;
 227         struct page **pages;
 228         int ret = 0;
 229         bool fast;
 230
 231         if (pin_longterm_test_pages)
 232                 return -EINVAL;
 233
 234         if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
 235                 return -EFAULT;
 236
 237         if (args.flags &
 238             ~(PIN_LONGTERM_TEST_FLAG_USE_WRITE|PIN_LONGTERM_TEST_FLAG_USE_FAST))
 239                 return -EINVAL;
 240         if (!IS_ALIGNED(args.addr | args.size, PAGE_SIZE))
 241                 return -EINVAL;
 242         if (args.size > LONG_MAX)
 243                 return -EINVAL;
 244         nr_pages = args.size / PAGE_SIZE;
 245         if (!nr_pages)
 246                 return -EINVAL;
 247
 248         pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
 249         if (!pages)
 250                 return -ENOMEM;
 251
 252         if (args.flags & PIN_LONGTERM_TEST_FLAG_USE_WRITE)
 253                 gup_flags |= FOLL_WRITE;
 254         fast = !!(args.flags & PIN_LONGTERM_TEST_FLAG_USE_FAST);
 255
 256         if (!fast && mmap_read_lock_killable(current->mm)) {
 257                 kvfree(pages);
 258                 return -EINTR;
 259         }
 260
 261         pin_longterm_test_pages = pages;
 262         pin_longterm_test_nr_pages = 0;
 263
 264         while (nr_pages - pin_longterm_test_nr_pages) {
 265                 remaining_pages = nr_pages - pin_longterm_test_nr_pages;
 266                 addr = args.addr + pin_longterm_test_nr_pages * PAGE_SIZE;
 267
 268                 if (fast)
 269                         cur_pages = pin_user_pages_fast(addr, remaining_pages,
 270                                                         gup_flags, pages);
 271                 else
 272                         cur_pages = pin_user_pages(addr, remaining_pages,
 273                                                    gup_flags, pages);
 274                 if (cur_pages < 0) {
 275                         pin_longterm_test_stop();
 276                         ret = cur_pages;
 277                         break;
 278                 }
 279                 pin_longterm_test_nr_pages += cur_pages;
 280                 pages += cur_pages;
 281         }
 282
 283         if (!fast)
 284                 mmap_read_unlock(current->mm);
 285         return ret;
 286 }
 287
 288 static inline int pin_longterm_test_read(unsigned long arg)
 289 {
 290         __u64 user_addr;
 291         unsigned long i;
 292
 293         if (!pin_longterm_test_pages)
 294                 return -EINVAL;
 295
 296         if (copy_from_user(&user_addr, (void __user *)arg, sizeof(user_addr)))
 297                 return -EFAULT;
 298
 299         for (i = 0; i < pin_longterm_test_nr_pages; i++) {
 300                 void *addr = kmap_local_page(pin_longterm_test_pages[i]);
 301                 unsigned long ret;
 302
 303                 ret = copy_to_user((void __user *)(unsigned long)user_addr, addr,
 304                                    PAGE_SIZE);
 305                 kunmap_local(addr);
 306                 if (ret)
 307                         return -EFAULT;
 308                 user_addr += PAGE_SIZE;
 309         }
 310         return 0;
 311 }
 312
 313 static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,
 314                                     unsigned long arg)
 315 {
 316         int ret = -EINVAL;
 317
 318         if (mutex_lock_killable(&pin_longterm_test_mutex))
 319                 return -EINTR;
 320
 321         switch (cmd) {
 322         case PIN_LONGTERM_TEST_START:
 323                 ret = pin_longterm_test_start(arg);
 324                 break;
 325         case PIN_LONGTERM_TEST_STOP:
 326                 pin_longterm_test_stop();
 327                 ret = 0;
 328                 break;
 329         case PIN_LONGTERM_TEST_READ:
 330                 ret = pin_longterm_test_read(arg);
 331                 break;
 332         }
 333
 334         mutex_unlock(&pin_longterm_test_mutex);
 335         return ret;
 336 }
 337
 338 static long gup_test_ioctl(struct file *filep, unsigned int cmd,
 339                 unsigned long arg)
 340 {
 341         struct gup_test gup;
 342         int ret;
 343
 344         switch (cmd) {
 345         case GUP_FAST_BENCHMARK:
 346         case PIN_FAST_BENCHMARK:
 347         case PIN_LONGTERM_BENCHMARK:
 348         case GUP_BASIC_TEST:
 349         case PIN_BASIC_TEST:
 350         case DUMP_USER_PAGES_TEST:
 351                 break;
 352         case PIN_LONGTERM_TEST_START:
 353         case PIN_LONGTERM_TEST_STOP:
 354         case PIN_LONGTERM_TEST_READ:
 355                 return pin_longterm_test_ioctl(filep, cmd, arg);
 356         default:
 357                 return -EINVAL;
 358         }
 359
 360         if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
 361                 return -EFAULT;
 362
 363         ret = __gup_test_ioctl(cmd, &gup);
 364         if (ret)
 365                 return ret;
 366
 367         if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
 368                 return -EFAULT;
 369
 370         return 0;
 371 }
 372
 373 static int gup_test_release(struct inode *inode, struct file *file)
 374 {
 375         pin_longterm_test_stop();
 376
 377         return 0;
 378 }
 379
 380 static const struct file_operations gup_test_fops = {
 381         .open = nonseekable_open,
 382         .unlocked_ioctl = gup_test_ioctl,
 383         .compat_ioctl = compat_ptr_ioctl,
 384         .release = gup_test_release,
 385 };
 386
 387 static int __init gup_test_init(void)
 388 {
 389         debugfs_create_file_unsafe("gup_test", 0600, NULL, NULL,
 390                                    &gup_test_fops);
 391
 392         return 0;
 393 }
 394
 395 late_initcall(gup_test_init);