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 #ifdef CONFIG_X86_64
  20         LOWEST_LEVEL            = 4,
  21         LPS                     = (1 << PMD_SHIFT),
  22 #elif defined(CONFIG_X86_PAE)
  23         LOWEST_LEVEL            = 4,
  24         LPS                     = (1 << PMD_SHIFT),
  25 #else
  26         LOWEST_LEVEL            = 4, /* 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         long i, expected, missed = 0;
  47         int printed = 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                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  55                 int level;
  56                 pte_t *pte;
  57
  58                 pte = lookup_address(addr, &level);
  59                 if (!pte) {
  60                         if (!printed) {
  61                                 dump_pagetable(addr);
  62                                 printk(KERN_INFO "CPA %lx no pte level %d\n",
  63                                         addr, level);
  64                                 printed = 1;
  65                         }
  66                         missed++;
  67                         i++;
  68                         continue;
  69                 }
  70
  71                 if (level == 2 && sizeof(long) == 8) {
  72                         s->gpg++;
  73                         i += GPS/PAGE_SIZE;
  74                 } else if (level != LOWEST_LEVEL) {
  75                         if (!(pte_val(*pte) & _PAGE_PSE)) {
  76                                 printk(KERN_ERR
  77                                         "%lx level %d but not PSE %Lx\n",
  78                                         addr, level, (u64)pte_val(*pte));
  79                                 err = 1;
  80                         }
  81                         s->lpg++;
  82                         i += LPS/PAGE_SIZE;
  83                 } else {
  84                         s->spg++;
  85                         i++;
  86                 }
  87                 if (!(pte_val(*pte) & _PAGE_NX)) {
  88                         s->exec++;
  89                         if (addr < s->min_exec)
  90                                 s->min_exec = addr;
  91                         if (addr > s->max_exec)
  92                                 s->max_exec = addr;
  93                 }
  94         }
  95         printk(KERN_INFO
  96                 "CPA mapping 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  97                 s->spg, s->lpg, s->gpg, s->exec,
  98                 s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed);
  99
 100         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
 101         if (expected != i) {
 102                 printk(KERN_ERR "CPA max_mapped %lu but expected %lu\n",
 103                         max_mapped, expected);
 104                 return 1;
 105         }
 106         return err;
 107 }
 108
 109 static unsigned long __initdata addr[NTEST];
 110 static unsigned int __initdata len[NTEST];
 111
 112 /* Change the global bit on random pages in the direct mapping */
 113 static __init int exercise_pageattr(void)
 114 {
 115         struct split_state sa, sb, sc;
 116         unsigned long *bm;
 117         pte_t *pte, pte0;
 118         int failed = 0;
 119         int level;
 120         int i, k;
 121         int err;
 122
 123         printk(KERN_INFO "CPA exercising pageattr\n");
 124
 125         bm = vmalloc((max_mapped + 7) / 8);
 126         if (!bm) {
 127                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 128                 return -ENOMEM;
 129         }
 130         memset(bm, 0, (max_mapped + 7) / 8);
 131
 132         failed += print_split(&sa);
 133         srandom32(100);
 134
 135         for (i = 0; i < NTEST; i++) {
 136                 unsigned long pfn = random32() % max_mapped;
 137
 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
 142                 if (len[i] == 0)
 143                         len[i] = 1;
 144
 145                 pte = NULL;
 146                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 147
 148                 for (k = 0; k < len[i]; k++) {
 149                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 150                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0) {
 151                                 addr[i] = 0;
 152                                 break;
 153                         }
 154                         if (k == 0) {
 155                                 pte0 = *pte;
 156                         } else {
 157                                 if (pgprot_val(pte_pgprot(*pte)) !=
 158                                         pgprot_val(pte_pgprot(pte0))) {
 159                                         len[i] = k;
 160                                         break;
 161                                 }
 162                         }
 163                         if (test_bit(pfn + k, bm)) {
 164                                 len[i] = k;
 165                                 break;
 166                         }
 167                         __set_bit(pfn + k, bm);
 168                 }
 169                 if (!addr[i] || !pte || !k) {
 170                         addr[i] = 0;
 171                         continue;
 172                 }
 173
 174                 err = change_page_attr_addr(addr[i], len[i],
 175                             pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
 176                 if (err < 0) {
 177                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 178                         failed++;
 179                 }
 180
 181                 pte = lookup_address(addr[i], &level);
 182                 if (!pte || pte_global(*pte) || pte_huge(*pte)) {
 183                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 184                                 pte ? (u64)pte_val(*pte) : 0ULL);
 185                         failed++;
 186                 }
 187                 if (level != LOWEST_LEVEL) {
 188                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 189                                 addr[i], level);
 190                         failed++;
 191                 }
 192
 193         }
 194         vfree(bm);
 195         global_flush_tlb();
 196
 197         failed += print_split(&sb);
 198
 199         printk(KERN_INFO "CPA reverting everything\n");
 200         for (i = 0; i < NTEST; i++) {
 201                 if (!addr[i])
 202                         continue;
 203                 pte = lookup_address(addr[i], &level);
 204                 if (!pte) {
 205                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 206                         failed++;
 207                         continue;
 208                 }
 209                 err = change_page_attr_addr(addr[i], len[i],
 210                                           pte_pgprot(pte_mkglobal(*pte)));
 211                 if (err < 0) {
 212                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 213                         failed++;
 214                 }
 215                 pte = lookup_address(addr[i], &level);
 216                 if (!pte || !pte_global(*pte)) {
 217                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 218                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 219                         failed++;
 220                 }
 221
 222         }
 223         global_flush_tlb();
 224
 225         failed += print_split(&sc);
 226
 227         if (failed) {
 228                 printk(KERN_ERR "CPA selftests NOT PASSED. Please report.\n");
 229                 WARN_ON(1);
 230         } else {
 231                 printk(KERN_INFO "CPA selftests PASSED\n");
 232         }
 233
 234         return 0;
 235 }
 236 module_init(exercise_pageattr);