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