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
   8 #include <linux/mm.h>
   9 #include <linux/random.h>
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/bootmem.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/kdebug.h>
  16
  17 enum {
  18         NTEST = 400,
  19 #ifdef CONFIG_X86_64
  20         LOWEST_LEVEL = 4,
  21         LPS = (1 << PMD_SHIFT),
  22 #elif defined(CONFIG_X86_PAE)
  23         LOWEST_LEVEL = 3,
  24         LPS = (1 << PMD_SHIFT),
  25 #else
  26         LOWEST_LEVEL = 3, /* lookup_address lies here */
  27         LPS = (1 << 22),
  28 #endif
  29         GPS = (1<<30)
  30 };
  31
  32 #ifdef CONFIG_X86_64
  33 #include <asm/proto.h>
  34 #define max_mapped end_pfn_map
  35 #else
  36 #define max_mapped max_low_pfn
  37 #endif
  38
  39 struct split_state {
  40         long lpg, gpg, spg, exec;
  41         long min_exec, max_exec;
  42 };
  43
  44 static __init int print_split(struct split_state *s)
  45 {
  46         int printed = 0;
  47         long i, expected, missed = 0;
  48         int err = 0;
  49
  50         s->lpg = s->gpg = s->spg = s->exec = 0;
  51         s->min_exec = ~0UL;
  52         s->max_exec = 0;
  53         for (i = 0; i < max_mapped; ) {
  54                 int level;
  55                 pte_t *pte;
  56                 unsigned long adr = (unsigned long)__va(i << PAGE_SHIFT);
  57
  58                 pte = lookup_address(adr, &level);
  59                 if (!pte) {
  60                         if (!printed) {
  61                                 dump_pagetable(adr);
  62                                 printk("CPA %lx no pte level %d\n", adr, level);
  63                                 printed = 1;
  64                         }
  65                         missed++;
  66                         i++;
  67                         continue;
  68                 }
  69
  70                 if (level == 2 && sizeof(long) == 8) {
  71                         s->gpg++;
  72                         i += GPS/PAGE_SIZE;
  73                 } else if (level != LOWEST_LEVEL) {
  74                         if (!(pte_val(*pte) & _PAGE_PSE)) {
  75                                 printk("%lx level %d but not PSE %Lx\n",
  76                                         adr, 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 (adr < s->min_exec)
  88                                 s->min_exec = adr;
  89                         if (adr > s->max_exec)
  90                                 s->max_exec = adr;
  91                 }
  92         }
  93         printk("CPA mapping 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  94                 s->spg, s->lpg, s->gpg, s->exec,
  95                 s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed);
  96         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
  97         if (expected != i) {
  98                 printk("CPA max_mapped %lu but expected %lu\n",
  99                         max_mapped, expected);
 100                 return 1;
 101         }
 102         return err;
 103 }
 104
 105 static __init int state_same(struct split_state *a, struct split_state *b)
 106 {
 107         return a->lpg == b->lpg && a->gpg == b->gpg && a->spg == b->spg &&
 108                         a->exec == b->exec;
 109 }
 110
 111 static unsigned long addr[NTEST] __initdata;
 112 static unsigned len[NTEST] __initdata;
 113
 114 /* Change the global bit on random pages in the direct mapping */
 115 static __init int exercise_pageattr(void)
 116 {
 117         int i, k;
 118         pte_t *pte, pte0;
 119         int level;
 120         int err;
 121         struct split_state sa, sb, sc;
 122         int failed = 0;
 123         unsigned long *bm;
 124
 125         printk("CPA exercising pageattr\n");
 126
 127         bm = vmalloc((max_mapped + 7) / 8);
 128         if (!bm) {
 129                 printk("CPA Cannot vmalloc bitmap\n");
 130                 return -ENOMEM;
 131         }
 132         memset(bm, 0, (max_mapped + 7) / 8);
 133
 134         failed += print_split(&sa);
 135         srandom32(100);
 136         for (i = 0; i < NTEST; i++) {
 137                 unsigned long pfn = random32() % max_mapped;
 138                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 139                 len[i] = random32() % 100;
 140                 len[i] = min_t(unsigned long, len[i], max_mapped - pfn - 1);
 141                 if (len[i] == 0)
 142                         len[i] = 1;
 143
 144                 pte = NULL;
 145                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 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                                 addr[i] = 0;
 150                                 break;
 151                         }
 152                         if (k == 0)
 153                                 pte0 = *pte;
 154                         else if (pgprot_val(pte_pgprot(*pte)) !=
 155                                         pgprot_val(pte_pgprot(pte0))) {
 156                                 len[i] = k;
 157                                 break;
 158                         }
 159                         if (test_bit(pfn + k, bm)) {
 160                                 len[i] = k;
 161                                 break;
 162                         }
 163                         __set_bit(pfn + k, bm);
 164                 }
 165                 if (!addr[i] || !pte || !k) {
 166                         addr[i] = 0;
 167                         continue;
 168                 }
 169
 170                 err = change_page_attr(virt_to_page(addr[i]), len[i],
 171                             pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
 172                 if (err < 0) {
 173                         printk("CPA %d failed %d\n", i, err);
 174                         failed++;
 175                 }
 176
 177                 pte = lookup_address(addr[i], &level);
 178                 if (!pte || pte_global(*pte) || pte_huge(*pte)) {
 179                         printk("CPA %lx: bad pte %Lx\n", addr[i],
 180                                 pte ? (u64)pte_val(*pte) : 0ULL);
 181                         failed++;
 182                 }
 183                 if (level != LOWEST_LEVEL) {
 184                         printk("CPA %lx: unexpected level %d\n", addr[i],
 185                                         level);
 186                         failed++;
 187                 }
 188
 189         }
 190         vfree(bm);
 191         global_flush_tlb();
 192
 193         failed += print_split(&sb);
 194
 195         printk("CPA reverting everything\n");
 196         for (i = 0; i < NTEST; i++) {
 197                 if (!addr[i])
 198                         continue;
 199                 pte = lookup_address(addr[i], &level);
 200                 if (!pte) {
 201                         printk("CPA lookup of %lx failed\n", addr[i]);
 202                         failed++;
 203                         continue;
 204                 }
 205                 err = change_page_attr(virt_to_page(addr[i]), len[i],
 206                                           pte_pgprot(pte_mkglobal(*pte)));
 207                 if (err < 0) {
 208                         printk("CPA reverting failed: %d\n", err);
 209                         failed++;
 210                 }
 211                 pte = lookup_address(addr[i], &level);
 212                 if (!pte || !pte_global(*pte)) {
 213                         printk("CPA %lx: bad pte after revert %Lx\n", addr[i],
 214                                pte ? (u64)pte_val(*pte) : 0ULL);
 215                         failed++;
 216                 }
 217
 218         }
 219         global_flush_tlb();
 220
 221         failed += print_split(&sc);
 222         if (!state_same(&sa, &sc))
 223                 failed++;
 224
 225         if (failed)
 226                 printk("CPA selftests NOT PASSED. Please report.\n");
 227         else
 228                 printk("CPA selftests PASSED\n");
 229
 230         return 0;
 231 }
 232
 233 module_init(exercise_pageattr);