arch/x86/mm/pageattr-test.c

   1 /*
   2  * self test for change_page_attr.
   3  *
   4  * Clears the a test pte bit on random pages in the direct mapping,
   5  * then reverts 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/mm.h>
  12
  13 #include <asm/cacheflush.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/kdebug.h>
  16
  17 /*
  18  * Only print the results of the first pass:
  19  */
  20 static __read_mostly int print = 1;
  21
  22 enum {
  23         NTEST                   = 400,
  24 #ifdef CONFIG_X86_64
  25         LPS                     = (1 << PMD_SHIFT),
  26 #elif defined(CONFIG_X86_PAE)
  27         LPS                     = (1 << PMD_SHIFT),
  28 #else
  29         LPS                     = (1 << 22),
  30 #endif
  31         GPS                     = (1<<30)
  32 };
  33
  34 #define PAGE_CPA_TEST   __pgprot(_PAGE_CPA_TEST)
  35
  36 static int pte_testbit(pte_t pte)
  37 {
  38         return pte_flags(pte) & _PAGE_SOFTW1;
  39 }
  40
  41 struct split_state {
  42         long lpg, gpg, spg, exec;
  43         long min_exec, max_exec;
  44 };
  45
  46 static int print_split(struct split_state *s)
  47 {
  48         long i, expected, missed = 0;
  49         int err = 0;
  50
  51         s->lpg = s->gpg = s->spg = s->exec = 0;
  52         s->min_exec = ~0UL;
  53         s->max_exec = 0;
  54         for (i = 0; i < max_pfn_mapped; ) {
  55                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  56                 unsigned int level;
  57                 pte_t *pte;
  58
  59                 pte = lookup_address(addr, &level);
  60                 if (!pte) {
  61                         missed++;
  62                         i++;
  63                         continue;
  64                 }
  65
  66                 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  67                         s->gpg++;
  68                         i += GPS/PAGE_SIZE;
  69                 } else if (level == PG_LEVEL_2M) {
  70                         if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
  71                                 printk(KERN_ERR
  72                                         "%lx level %d but not PSE %Lx\n",
  73                                         addr, level, (u64)pte_val(*pte));
  74                                 err = 1;
  75                         }
  76                         s->lpg++;
  77                         i += LPS/PAGE_SIZE;
  78                 } else {
  79                         s->spg++;
  80                         i++;
  81                 }
  82                 if (!(pte_val(*pte) & _PAGE_NX)) {
  83                         s->exec++;
  84                         if (addr < s->min_exec)
  85                                 s->min_exec = addr;
  86                         if (addr > s->max_exec)
  87                                 s->max_exec = addr;
  88                 }
  89         }
  90         if (print) {
  91                 printk(KERN_INFO
  92                         " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  93                         s->spg, s->lpg, s->gpg, s->exec,
  94                         s->min_exec != ~0UL ? s->min_exec : 0,
  95                         s->max_exec, missed);
  96         }
  97
  98         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
  99         if (expected != i) {
 100                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
 101                         max_pfn_mapped, expected);
 102                 return 1;
 103         }
 104         return err;
 105 }
 106
 107 static unsigned long addr[NTEST];
 108 static unsigned int len[NTEST];
 109
 110 /* Change the global bit on random pages in the direct mapping */
 111 static int pageattr_test(void)
 112 {
 113         struct split_state sa, sb, sc;
 114         unsigned long *bm;
 115         pte_t *pte, pte0;
 116         int failed = 0;
 117         unsigned int level;
 118         int i, k;
 119         int err;
 120         unsigned long test_addr;
 121
 122         if (print)
 123                 printk(KERN_INFO "CPA self-test:\n");
 124
 125         bm = vzalloc((max_pfn_mapped + 7) / 8);
 126         if (!bm) {
 127                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 128                 return -ENOMEM;
 129         }
 130
 131         failed += print_split(&sa);
 132
 133         for (i = 0; i < NTEST; i++) {
 134                 unsigned long pfn = prandom_u32() % max_pfn_mapped;
 135
 136                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 137                 len[i] = prandom_u32() % 100;
 138                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 139
 140                 if (len[i] == 0)
 141                         len[i] = 1;
 142
 143                 pte = NULL;
 144                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 145
 146                 for (k = 0; k < len[i]; k++) {
 147                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 148                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
 149                             !(pte_val(*pte) & _PAGE_PRESENT)) {
 150                                 addr[i] = 0;
 151                                 break;
 152                         }
 153                         if (k == 0) {
 154                                 pte0 = *pte;
 155                         } else {
 156                                 if (pgprot_val(pte_pgprot(*pte)) !=
 157                                         pgprot_val(pte_pgprot(pte0))) {
 158                                         len[i] = k;
 159                                         break;
 160                                 }
 161                         }
 162                         if (test_bit(pfn + k, bm)) {
 163                                 len[i] = k;
 164                                 break;
 165                         }
 166                         __set_bit(pfn + k, bm);
 167                 }
 168                 if (!addr[i] || !pte || !k) {
 169                         addr[i] = 0;
 170                         continue;
 171                 }
 172
 173                 test_addr = addr[i];
 174                 err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0);
 175                 if (err < 0) {
 176                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 177                         failed++;
 178                 }
 179
 180                 pte = lookup_address(addr[i], &level);
 181                 if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
 182                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 183                                 pte ? (u64)pte_val(*pte) : 0ULL);
 184                         failed++;
 185                 }
 186                 if (level != PG_LEVEL_4K) {
 187                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 188                                 addr[i], level);
 189                         failed++;
 190                 }
 191
 192         }
 193         vfree(bm);
 194
 195         failed += print_split(&sb);
 196
 197         for (i = 0; i < NTEST; i++) {
 198                 if (!addr[i])
 199                         continue;
 200                 pte = lookup_address(addr[i], &level);
 201                 if (!pte) {
 202                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 203                         failed++;
 204                         continue;
 205                 }
 206                 test_addr = addr[i];
 207                 err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0);
 208                 if (err < 0) {
 209                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 210                         failed++;
 211                 }
 212                 pte = lookup_address(addr[i], &level);
 213                 if (!pte || pte_testbit(*pte)) {
 214                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 215                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 216                         failed++;
 217                 }
 218
 219         }
 220
 221         failed += print_split(&sc);
 222
 223         if (failed) {
 224                 WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
 225                 return -EINVAL;
 226         } else {
 227                 if (print)
 228                         printk(KERN_INFO "ok.\n");
 229         }
 230
 231         return 0;
 232 }
 233
 234 static int do_pageattr_test(void *__unused)
 235 {
 236         while (!kthread_should_stop()) {
 237                 schedule_timeout_interruptible(HZ*30);
 238                 if (pageattr_test() < 0)
 239                         break;
 240                 if (print)
 241                         print--;
 242         }
 243         return 0;
 244 }
 245
 246 static int start_pageattr_test(void)
 247 {
 248         struct task_struct *p;
 249
 250         p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
 251         if (!IS_ERR(p))
 252                 wake_up_process(p);
 253         else
 254                 WARN_ON(1);
 255
 256         return 0;
 257 }
 258
 259 module_init(start_pageattr_test);