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/random.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/mm.h>
  12
  13 #include <asm/cacheflush.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/kdebug.h>
  16
  17 enum {
  18         NTEST                   = 4000,
  19 #ifdef CONFIG_X86_64
  20         LPS                     = (1 << PMD_SHIFT),
  21 #elif defined(CONFIG_X86_PAE)
  22         LPS                     = (1 << PMD_SHIFT),
  23 #else
  24         LPS                     = (1 << 22),
  25 #endif
  26         GPS                     = (1<<30)
  27 };
  28
  29 struct split_state {
  30         long lpg, gpg, spg, exec;
  31         long min_exec, max_exec;
  32 };
  33
  34 static __init int print_split(struct split_state *s)
  35 {
  36         long i, expected, missed = 0;
  37         int printed = 0;
  38         int err = 0;
  39
  40         s->lpg = s->gpg = s->spg = s->exec = 0;
  41         s->min_exec = ~0UL;
  42         s->max_exec = 0;
  43         for (i = 0; i < max_pfn_mapped; ) {
  44                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  45                 unsigned int level;
  46                 pte_t *pte;
  47
  48                 pte = lookup_address(addr, &level);
  49                 if (!pte) {
  50                         if (!printed) {
  51                                 dump_pagetable(addr);
  52                                 printk(KERN_INFO "CPA %lx no pte level %d\n",
  53                                         addr, level);
  54                                 printed = 1;
  55                         }
  56                         missed++;
  57                         i++;
  58                         continue;
  59                 }
  60
  61                 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  62                         s->gpg++;
  63                         i += GPS/PAGE_SIZE;
  64                 } else if (level == PG_LEVEL_2M) {
  65                         if (!(pte_val(*pte) & _PAGE_PSE)) {
  66                                 printk(KERN_ERR
  67                                         "%lx level %d but not PSE %Lx\n",
  68                                         addr, level, (u64)pte_val(*pte));
  69                                 err = 1;
  70                         }
  71                         s->lpg++;
  72                         i += LPS/PAGE_SIZE;
  73                 } else {
  74                         s->spg++;
  75                         i++;
  76                 }
  77                 if (!(pte_val(*pte) & _PAGE_NX)) {
  78                         s->exec++;
  79                         if (addr < s->min_exec)
  80                                 s->min_exec = addr;
  81                         if (addr > s->max_exec)
  82                                 s->max_exec = addr;
  83                 }
  84         }
  85         printk(KERN_INFO
  86                 "CPA mapping 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, s->max_exec, missed);
  89
  90         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
  91         if (expected != i) {
  92                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
  93                         max_pfn_mapped, expected);
  94                 return 1;
  95         }
  96         return err;
  97 }
  98
  99 static unsigned long __initdata addr[NTEST];
 100 static unsigned int __initdata len[NTEST];
 101
 102 /* Change the global bit on random pages in the direct mapping */
 103 static __init int exercise_pageattr(void)
 104 {
 105         struct split_state sa, sb, sc;
 106         unsigned long *bm;
 107         pte_t *pte, pte0;
 108         int failed = 0;
 109         unsigned int level;
 110         int i, k;
 111         int err;
 112
 113         printk(KERN_INFO "CPA exercising pageattr\n");
 114
 115         bm = vmalloc((max_pfn_mapped + 7) / 8);
 116         if (!bm) {
 117                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 118                 return -ENOMEM;
 119         }
 120         memset(bm, 0, (max_pfn_mapped + 7) / 8);
 121
 122         failed += print_split(&sa);
 123         srandom32(100);
 124
 125         for (i = 0; i < NTEST; i++) {
 126                 unsigned long pfn = random32() % max_pfn_mapped;
 127
 128                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 129                 len[i] = random32() % 100;
 130                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 131
 132                 if (len[i] == 0)
 133                         len[i] = 1;
 134
 135                 pte = NULL;
 136                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 137
 138                 for (k = 0; k < len[i]; k++) {
 139                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 140                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0) {
 141                                 addr[i] = 0;
 142                                 break;
 143                         }
 144                         if (k == 0) {
 145                                 pte0 = *pte;
 146                         } else {
 147                                 if (pgprot_val(pte_pgprot(*pte)) !=
 148                                         pgprot_val(pte_pgprot(pte0))) {
 149                                         len[i] = k;
 150                                         break;
 151                                 }
 152                         }
 153                         if (test_bit(pfn + k, bm)) {
 154                                 len[i] = k;
 155                                 break;
 156                         }
 157                         __set_bit(pfn + k, bm);
 158                 }
 159                 if (!addr[i] || !pte || !k) {
 160                         addr[i] = 0;
 161                         continue;
 162                 }
 163
 164                 err = change_page_attr_clear(addr[i], len[i],
 165                                                __pgprot(_PAGE_GLOBAL));
 166                 if (err < 0) {
 167                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 168                         failed++;
 169                 }
 170
 171                 pte = lookup_address(addr[i], &level);
 172                 if (!pte || pte_global(*pte) || pte_huge(*pte)) {
 173                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 174                                 pte ? (u64)pte_val(*pte) : 0ULL);
 175                         failed++;
 176                 }
 177                 if (level != PG_LEVEL_4K) {
 178                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 179                                 addr[i], level);
 180                         failed++;
 181                 }
 182
 183         }
 184         vfree(bm);
 185
 186         failed += print_split(&sb);
 187
 188         printk(KERN_INFO "CPA reverting everything\n");
 189         for (i = 0; i < NTEST; i++) {
 190                 if (!addr[i])
 191                         continue;
 192                 pte = lookup_address(addr[i], &level);
 193                 if (!pte) {
 194                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 195                         failed++;
 196                         continue;
 197                 }
 198                 err = change_page_attr_set(addr[i], len[i],
 199                                              __pgprot(_PAGE_GLOBAL));
 200                 if (err < 0) {
 201                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 202                         failed++;
 203                 }
 204                 pte = lookup_address(addr[i], &level);
 205                 if (!pte || !pte_global(*pte)) {
 206                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 207                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 208                         failed++;
 209                 }
 210
 211         }
 212
 213         failed += print_split(&sc);
 214
 215         if (failed) {
 216                 printk(KERN_ERR "CPA selftests NOT PASSED. Please report.\n");
 217                 WARN_ON(1);
 218         } else {
 219                 printk(KERN_INFO "CPA selftests PASSED\n");
 220         }
 221
 222         return 0;
 223 }
 224 module_init(exercise_pageattr);