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                   = 400,
  19         LOWEST_LEVEL            = PG_LEVEL_4K,
  20 #ifdef CONFIG_X86_64
  21         LPS                     = (1 << PMD_SHIFT),
  22 #elif defined(CONFIG_X86_PAE)
  23         LPS                     = (1 << PMD_SHIFT),
  24 #else
  25         LPS                     = (1 << 22),
  26 #endif
  27         GPS                     = (1<<30)
  28 };
  29
  30 struct split_state {
  31         long lpg, gpg, spg, exec;
  32         long min_exec, max_exec;
  33 };
  34
  35 static __init int print_split(struct split_state *s)
  36 {
  37         long i, expected, missed = 0;
  38         int printed = 0;
  39         int err = 0;
  40
  41         s->lpg = s->gpg = s->spg = s->exec = 0;
  42         s->min_exec = ~0UL;
  43         s->max_exec = 0;
  44         for (i = 0; i < max_pfn_mapped; ) {
  45                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  46                 int level;
  47                 pte_t *pte;
  48
  49                 pte = lookup_address(addr, &level);
  50                 if (!pte) {
  51                         if (!printed) {
  52                                 dump_pagetable(addr);
  53                                 printk(KERN_INFO "CPA %lx no pte level %d\n",
  54                                         addr, level);
  55                                 printed = 1;
  56                         }
  57                         missed++;
  58                         i++;
  59                         continue;
  60                 }
  61
  62                 if (level == 2 && sizeof(long) == 8) {
  63                         s->gpg++;
  64                         i += GPS/PAGE_SIZE;
  65                 } else if (level != LOWEST_LEVEL) {
  66                         if (!(pte_val(*pte) & _PAGE_PSE)) {
  67                                 printk(KERN_ERR
  68                                         "%lx level %d but not PSE %Lx\n",
  69                                         addr, level, (u64)pte_val(*pte));
  70                                 err = 1;
  71                         }
  72                         s->lpg++;
  73                         i += LPS/PAGE_SIZE;
  74                 } else {
  75                         s->spg++;
  76                         i++;
  77                 }
  78                 if (!(pte_val(*pte) & _PAGE_NX)) {
  79                         s->exec++;
  80                         if (addr < s->min_exec)
  81                                 s->min_exec = addr;
  82                         if (addr > s->max_exec)
  83                                 s->max_exec = addr;
  84                 }
  85         }
  86         printk(KERN_INFO
  87                 "CPA mapping 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  88                 s->spg, s->lpg, s->gpg, s->exec,
  89                 s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed);
  90
  91         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
  92         if (expected != i) {
  93                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
  94                         max_pfn_mapped, expected);
  95                 return 1;
  96         }
  97         return err;
  98 }
  99
 100 static unsigned long __initdata addr[NTEST];
 101 static unsigned int __initdata len[NTEST];
 102
 103 /* Change the global bit on random pages in the direct mapping */
 104 static __init int exercise_pageattr(void)
 105 {
 106         struct split_state sa, sb, sc;
 107         unsigned long *bm;
 108         pte_t *pte, pte0;
 109         int failed = 0;
 110         int level;
 111         int i, k;
 112         int err;
 113
 114         printk(KERN_INFO "CPA exercising pageattr\n");
 115
 116         bm = vmalloc((max_pfn_mapped + 7) / 8);
 117         if (!bm) {
 118                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 119                 return -ENOMEM;
 120         }
 121         memset(bm, 0, (max_pfn_mapped + 7) / 8);
 122
 123         failed += print_split(&sa);
 124         srandom32(100);
 125
 126         for (i = 0; i < NTEST; i++) {
 127                 unsigned long pfn = random32() % max_pfn_mapped;
 128
 129                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 130                 len[i] = random32() % 100;
 131                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 132
 133                 if (len[i] == 0)
 134                         len[i] = 1;
 135
 136                 pte = NULL;
 137                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 138
 139                 for (k = 0; k < len[i]; k++) {
 140                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 141                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0) {
 142                                 addr[i] = 0;
 143                                 break;
 144                         }
 145                         if (k == 0) {
 146                                 pte0 = *pte;
 147                         } else {
 148                                 if (pgprot_val(pte_pgprot(*pte)) !=
 149                                         pgprot_val(pte_pgprot(pte0))) {
 150                                         len[i] = k;
 151                                         break;
 152                                 }
 153                         }
 154                         if (test_bit(pfn + k, bm)) {
 155                                 len[i] = k;
 156                                 break;
 157                         }
 158                         __set_bit(pfn + k, bm);
 159                 }
 160                 if (!addr[i] || !pte || !k) {
 161                         addr[i] = 0;
 162                         continue;
 163                 }
 164
 165                 err = change_page_attr_addr(addr[i], len[i],
 166                             pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
 167                 if (err < 0) {
 168                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 169                         failed++;
 170                 }
 171
 172                 pte = lookup_address(addr[i], &level);
 173                 if (!pte || pte_global(*pte) || pte_huge(*pte)) {
 174                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 175                                 pte ? (u64)pte_val(*pte) : 0ULL);
 176                         failed++;
 177                 }
 178                 if (level != LOWEST_LEVEL) {
 179                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 180                                 addr[i], level);
 181                         failed++;
 182                 }
 183
 184         }
 185         vfree(bm);
 186         global_flush_tlb();
 187
 188         failed += print_split(&sb);
 189
 190         printk(KERN_INFO "CPA reverting everything\n");
 191         for (i = 0; i < NTEST; i++) {
 192                 if (!addr[i])
 193                         continue;
 194                 pte = lookup_address(addr[i], &level);
 195                 if (!pte) {
 196                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 197                         failed++;
 198                         continue;
 199                 }
 200                 err = change_page_attr_addr(addr[i], len[i],
 201                                           pte_pgprot(pte_mkglobal(*pte)));
 202                 if (err < 0) {
 203                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 204                         failed++;
 205                 }
 206                 pte = lookup_address(addr[i], &level);
 207                 if (!pte || !pte_global(*pte)) {
 208                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 209                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 210                         failed++;
 211                 }
 212
 213         }
 214         global_flush_tlb();
 215
 216         failed += print_split(&sc);
 217
 218         if (failed) {
 219                 printk(KERN_ERR "CPA selftests NOT PASSED. Please report.\n");
 220                 WARN_ON(1);
 221         } else {
 222                 printk(KERN_INFO "CPA selftests PASSED\n");
 223         }
 224
 225         return 0;
 226 }
 227 module_init(exercise_pageattr);