arch/x86/mm/pat/cpa-test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * self test for change_page_attr.
   4  *
   5  * Clears the a test pte bit on random pages in the direct mapping,
   6  * then reverts and compares page tables forwards and afterwards.
   7  */
   8 #include <linux/memblock.h>
   9 #include <linux/kthread.h>
  10 #include <linux/random.h>
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/mm.h>
  14 #include <linux/vmalloc.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/kdebug.h>
  18
  19 /*
  20  * Only print the results of the first pass:
  21  */
  22 static __read_mostly int print = 1;
  23
  24 enum {
  25         NTEST                   = 3 * 100,
  26         NPAGES                  = 100,
  27 #ifdef CONFIG_X86_64
  28         LPS                     = (1 << PMD_SHIFT),
  29 #elif defined(CONFIG_X86_PAE)
  30         LPS                     = (1 << PMD_SHIFT),
  31 #else
  32         LPS                     = (1 << 22),
  33 #endif
  34         GPS                     = (1<<30)
  35 };
  36
  37 #define PAGE_CPA_TEST   __pgprot(_PAGE_CPA_TEST)
  38
  39 static int pte_testbit(pte_t pte)
  40 {
  41         return pte_flags(pte) & _PAGE_SOFTW1;
  42 }
  43
  44 struct split_state {
  45         long lpg, gpg, spg, exec;
  46         long min_exec, max_exec;
  47 };
  48
  49 static int print_split(struct split_state *s)
  50 {
  51         long i, expected, missed = 0;
  52         int err = 0;
  53
  54         s->lpg = s->gpg = s->spg = s->exec = 0;
  55         s->min_exec = ~0UL;
  56         s->max_exec = 0;
  57         for (i = 0; i < max_pfn_mapped; ) {
  58                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  59                 unsigned int level;
  60                 pte_t *pte;
  61
  62                 pte = lookup_address(addr, &level);
  63                 if (!pte) {
  64                         missed++;
  65                         i++;
  66                         continue;
  67                 }
  68
  69                 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  70                         s->gpg++;
  71                         i += GPS/PAGE_SIZE;
  72                 } else if (level == PG_LEVEL_2M) {
  73                         if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
  74                                 printk(KERN_ERR
  75                                         "%lx level %d but not PSE %Lx\n",
  76                                         addr, level, (u64)pte_val(*pte));
  77                                 err = 1;
  78                         }
  79                         s->lpg++;
  80                         i += LPS/PAGE_SIZE;
  81                 } else {
  82                         s->spg++;
  83                         i++;
  84                 }
  85                 if (!(pte_val(*pte) & _PAGE_NX)) {
  86                         s->exec++;
  87                         if (addr < s->min_exec)
  88                                 s->min_exec = addr;
  89                         if (addr > s->max_exec)
  90                                 s->max_exec = addr;
  91                 }
  92         }
  93         if (print) {
  94                 printk(KERN_INFO
  95                         " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  96                         s->spg, s->lpg, s->gpg, s->exec,
  97                         s->min_exec != ~0UL ? s->min_exec : 0,
  98                         s->max_exec, missed);
  99         }
 100
 101         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
 102         if (expected != i) {
 103                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
 104                         max_pfn_mapped, expected);
 105                 return 1;
 106         }
 107         return err;
 108 }
 109
 110 static unsigned long addr[NTEST];
 111 static unsigned int len[NTEST];
 112
 113 static struct page *pages[NPAGES];
 114 static unsigned long addrs[NPAGES];
 115
 116 /* Change the global bit on random pages in the direct mapping */
 117 static int pageattr_test(void)
 118 {
 119         struct split_state sa, sb, sc;
 120         unsigned long *bm;
 121         pte_t *pte, pte0;
 122         int failed = 0;
 123         unsigned int level;
 124         int i, k;
 125         int err;
 126
 127         if (print)
 128                 printk(KERN_INFO "CPA self-test:\n");
 129
 130         bm = vzalloc((max_pfn_mapped + 7) / 8);
 131         if (!bm) {
 132                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 133                 return -ENOMEM;
 134         }
 135
 136         failed += print_split(&sa);
 137
 138         for (i = 0; i < NTEST; i++) {
 139                 unsigned long pfn = prandom_u32() % max_pfn_mapped;
 140
 141                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 142                 len[i] = prandom_u32() % NPAGES;
 143                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 144
 145                 if (len[i] == 0)
 146                         len[i] = 1;
 147
 148                 pte = NULL;
 149                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 150
 151                 for (k = 0; k < len[i]; k++) {
 152                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 153                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
 154                             !(pte_val(*pte) & _PAGE_PRESENT)) {
 155                                 addr[i] = 0;
 156                                 break;
 157                         }
 158                         if (k == 0) {
 159                                 pte0 = *pte;
 160                         } else {
 161                                 if (pgprot_val(pte_pgprot(*pte)) !=
 162                                         pgprot_val(pte_pgprot(pte0))) {
 163                                         len[i] = k;
 164                                         break;
 165                                 }
 166                         }
 167                         if (test_bit(pfn + k, bm)) {
 168                                 len[i] = k;
 169                                 break;
 170                         }
 171                         __set_bit(pfn + k, bm);
 172                         addrs[k] = addr[i] + k*PAGE_SIZE;
 173                         pages[k] = pfn_to_page(pfn + k);
 174                 }
 175                 if (!addr[i] || !pte || !k) {
 176                         addr[i] = 0;
 177                         continue;
 178                 }
 179
 180                 switch (i % 3) {
 181                 case 0:
 182                         err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
 183                         break;
 184
 185                 case 1:
 186                         err = change_page_attr_set(addrs, len[1], PAGE_CPA_TEST, 1);
 187                         break;
 188
 189                 case 2:
 190                         err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
 191                         break;
 192                 }
 193
 194
 195                 if (err < 0) {
 196                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 197                         failed++;
 198                 }
 199
 200                 pte = lookup_address(addr[i], &level);
 201                 if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
 202                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 203                                 pte ? (u64)pte_val(*pte) : 0ULL);
 204                         failed++;
 205                 }
 206                 if (level != PG_LEVEL_4K) {
 207                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 208                                 addr[i], level);
 209                         failed++;
 210                 }
 211
 212         }
 213         vfree(bm);
 214
 215         failed += print_split(&sb);
 216
 217         for (i = 0; i < NTEST; i++) {
 218                 if (!addr[i])
 219                         continue;
 220                 pte = lookup_address(addr[i], &level);
 221                 if (!pte) {
 222                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 223                         failed++;
 224                         continue;
 225                 }
 226                 err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
 227                 if (err < 0) {
 228                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 229                         failed++;
 230                 }
 231                 pte = lookup_address(addr[i], &level);
 232                 if (!pte || pte_testbit(*pte)) {
 233                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 234                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 235                         failed++;
 236                 }
 237
 238         }
 239
 240         failed += print_split(&sc);
 241
 242         if (failed) {
 243                 WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
 244                 return -EINVAL;
 245         } else {
 246                 if (print)
 247                         printk(KERN_INFO "ok.\n");
 248         }
 249
 250         return 0;
 251 }
 252
 253 static int do_pageattr_test(void *__unused)
 254 {
 255         while (!kthread_should_stop()) {
 256                 schedule_timeout_interruptible(HZ*30);
 257                 if (pageattr_test() < 0)
 258                         break;
 259                 if (print)
 260                         print--;
 261         }
 262         return 0;
 263 }
 264
 265 static int start_pageattr_test(void)
 266 {
 267         struct task_struct *p;
 268
 269         p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
 270         if (!IS_ERR(p))
 271                 wake_up_process(p);
 272         else
 273                 WARN_ON(1);
 274
 275         return 0;
 276 }
 277 device_initcall(start_pageattr_test);