arch/x86/mm/pageattr-test.c

   1 /*
   2  * self test for change_page_attr.
   3  *
   4  * Clears the global bit on random pages in the direct mapping, then reverts
   5  * and compares page tables forwards and afterwards.
   6  */
   7 #include <linux/bootmem.h>
   8 #include <linux/kthread.h>
   9 #include <linux/random.h>
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/mm.h>
  13
  14 #include <asm/cacheflush.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/kdebug.h>
  17
  18 /*
  19  * Only print the results of the first pass:
  20  */
  21 static __read_mostly int print = 1;
  22
  23 enum {
  24         NTEST                   = 400,
  25 #ifdef CONFIG_X86_64
  26         LPS                     = (1 << PMD_SHIFT),
  27 #elif defined(CONFIG_X86_PAE)
  28         LPS                     = (1 << PMD_SHIFT),
  29 #else
  30         LPS                     = (1 << 22),
  31 #endif
  32         GPS                     = (1<<30)
  33 };
  34
  35 struct split_state {
  36         long lpg, gpg, spg, exec;
  37         long min_exec, max_exec;
  38 };
  39
  40 static int print_split(struct split_state *s)
  41 {
  42         long i, expected, missed = 0;
  43         int err = 0;
  44
  45         s->lpg = s->gpg = s->spg = s->exec = 0;
  46         s->min_exec = ~0UL;
  47         s->max_exec = 0;
  48         for (i = 0; i < max_pfn_mapped; ) {
  49                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  50                 unsigned int level;
  51                 pte_t *pte;
  52
  53                 pte = lookup_address(addr, &level);
  54                 if (!pte) {
  55                         missed++;
  56                         i++;
  57                         continue;
  58                 }
  59
  60                 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  61                         s->gpg++;
  62                         i += GPS/PAGE_SIZE;
  63                 } else if (level == PG_LEVEL_2M) {
  64                         if (!(pte_val(*pte) & _PAGE_PSE)) {
  65                                 printk(KERN_ERR
  66                                         "%lx level %d but not PSE %Lx\n",
  67                                         addr, level, (u64)pte_val(*pte));
  68                                 err = 1;
  69                         }
  70                         s->lpg++;
  71                         i += LPS/PAGE_SIZE;
  72                 } else {
  73                         s->spg++;
  74                         i++;
  75                 }
  76                 if (!(pte_val(*pte) & _PAGE_NX)) {
  77                         s->exec++;
  78                         if (addr < s->min_exec)
  79                                 s->min_exec = addr;
  80                         if (addr > s->max_exec)
  81                                 s->max_exec = addr;
  82                 }
  83         }
  84         if (print) {
  85                 printk(KERN_INFO
  86                         " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  87                         s->spg, s->lpg, s->gpg, s->exec,
  88                         s->min_exec != ~0UL ? s->min_exec : 0,
  89                         s->max_exec, missed);
  90         }
  91
  92         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
  93         if (expected != i) {
  94                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
  95                         max_pfn_mapped, expected);
  96                 return 1;
  97         }
  98         return err;
  99 }
 100
 101 static unsigned long addr[NTEST];
 102 static unsigned int len[NTEST];
 103
 104 /* Change the global bit on random pages in the direct mapping */
 105 static int pageattr_test(void)
 106 {
 107         struct split_state sa, sb, sc;
 108         unsigned long *bm;
 109         pte_t *pte, pte0;
 110         int failed = 0;
 111         unsigned int level;
 112         int i, k;
 113         int err;
 114
 115         if (print)
 116                 printk(KERN_INFO "CPA self-test:\n");
 117
 118         bm = vmalloc((max_pfn_mapped + 7) / 8);
 119         if (!bm) {
 120                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 121                 return -ENOMEM;
 122         }
 123         memset(bm, 0, (max_pfn_mapped + 7) / 8);
 124
 125         failed += print_split(&sa);
 126         srandom32(100);
 127
 128         for (i = 0; i < NTEST; i++) {
 129                 unsigned long pfn = random32() % max_pfn_mapped;
 130
 131                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 132                 len[i] = random32() % 100;
 133                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 134
 135                 if (len[i] == 0)
 136                         len[i] = 1;
 137
 138                 pte = NULL;
 139                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 140
 141                 for (k = 0; k < len[i]; k++) {
 142                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 143                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
 144                             !(pte_val(*pte) & _PAGE_PRESENT)) {
 145                                 addr[i] = 0;
 146                                 break;
 147                         }
 148                         if (k == 0) {
 149                                 pte0 = *pte;
 150                         } else {
 151                                 if (pgprot_val(pte_pgprot(*pte)) !=
 152                                         pgprot_val(pte_pgprot(pte0))) {
 153                                         len[i] = k;
 154                                         break;
 155                                 }
 156                         }
 157                         if (test_bit(pfn + k, bm)) {
 158                                 len[i] = k;
 159                                 break;
 160                         }
 161                         __set_bit(pfn + k, bm);
 162                 }
 163                 if (!addr[i] || !pte || !k) {
 164                         addr[i] = 0;
 165                         continue;
 166                 }
 167
 168                 err = change_page_attr_clear(addr[i], len[i],
 169                                                __pgprot(_PAGE_GLOBAL));
 170                 if (err < 0) {
 171                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 172                         failed++;
 173                 }
 174
 175                 pte = lookup_address(addr[i], &level);
 176                 if (!pte || pte_global(*pte) || pte_huge(*pte)) {
 177                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 178                                 pte ? (u64)pte_val(*pte) : 0ULL);
 179                         failed++;
 180                 }
 181                 if (level != PG_LEVEL_4K) {
 182                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 183                                 addr[i], level);
 184                         failed++;
 185                 }
 186
 187         }
 188         vfree(bm);
 189
 190         failed += print_split(&sb);
 191
 192         for (i = 0; i < NTEST; i++) {
 193                 if (!addr[i])
 194                         continue;
 195                 pte = lookup_address(addr[i], &level);
 196                 if (!pte) {
 197                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 198                         failed++;
 199                         continue;
 200                 }
 201                 err = change_page_attr_set(addr[i], len[i],
 202                                              __pgprot(_PAGE_GLOBAL));
 203                 if (err < 0) {
 204                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 205                         failed++;
 206                 }
 207                 pte = lookup_address(addr[i], &level);
 208                 if (!pte || !pte_global(*pte)) {
 209                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 210                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 211                         failed++;
 212                 }
 213
 214         }
 215
 216         failed += print_split(&sc);
 217
 218         if (failed) {
 219                 printk(KERN_ERR "NOT PASSED. Please report.\n");
 220                 WARN_ON(1);
 221                 return -EINVAL;
 222         } else {
 223                 if (print)
 224                         printk(KERN_INFO "ok.\n");
 225         }
 226
 227         return 0;
 228 }
 229
 230 static int do_pageattr_test(void *__unused)
 231 {
 232         while (!kthread_should_stop()) {
 233                 schedule_timeout_interruptible(HZ*30);
 234                 if (pageattr_test() < 0)
 235                         break;
 236                 if (print)
 237                         print--;
 238         }
 239         return 0;
 240 }
 241
 242 static int start_pageattr_test(void)
 243 {
 244         struct task_struct *p;
 245
 246         p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
 247         if (!IS_ERR(p))
 248                 wake_up_process(p);
 249         else
 250                 WARN_ON(1);
 251
 252         return 0;
 253 }
 254
 255 module_init(start_pageattr_test);