arch/x86/mm/pageattr-test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * self test for change_page_attr.
   4  *
   5  * Clears the a test pte bit on random pages in the direct mapping,
   6  * then reverts and compares page tables forwards and afterwards.
   7  */
   8 #include <linux/memblock.h>
   9 #include <linux/kthread.h>
  10 #include <linux/random.h>
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/mm.h>
  14 #include <linux/vmalloc.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/kdebug.h>
  19
  20 /*
  21  * Only print the results of the first pass:
  22  */
  23 static __read_mostly int print = 1;
  24
  25 enum {
  26         NTEST                   = 3 * 100,
  27         NPAGES                  = 100,
  28 #ifdef CONFIG_X86_64
  29         LPS                     = (1 << PMD_SHIFT),
  30 #elif defined(CONFIG_X86_PAE)
  31         LPS                     = (1 << PMD_SHIFT),
  32 #else
  33         LPS                     = (1 << 22),
  34 #endif
  35         GPS                     = (1<<30)
  36 };
  37
  38 #define PAGE_CPA_TEST   __pgprot(_PAGE_CPA_TEST)
  39
  40 static int pte_testbit(pte_t pte)
  41 {
  42         return pte_flags(pte) & _PAGE_SOFTW1;
  43 }
  44
  45 struct split_state {
  46         long lpg, gpg, spg, exec;
  47         long min_exec, max_exec;
  48 };
  49
  50 static int print_split(struct split_state *s)
  51 {
  52         long i, expected, missed = 0;
  53         int err = 0;
  54
  55         s->lpg = s->gpg = s->spg = s->exec = 0;
  56         s->min_exec = ~0UL;
  57         s->max_exec = 0;
  58         for (i = 0; i < max_pfn_mapped; ) {
  59                 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  60                 unsigned int level;
  61                 pte_t *pte;
  62
  63                 pte = lookup_address(addr, &level);
  64                 if (!pte) {
  65                         missed++;
  66                         i++;
  67                         continue;
  68                 }
  69
  70                 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  71                         s->gpg++;
  72                         i += GPS/PAGE_SIZE;
  73                 } else if (level == PG_LEVEL_2M) {
  74                         if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
  75                                 printk(KERN_ERR
  76                                         "%lx level %d but not PSE %Lx\n",
  77                                         addr, level, (u64)pte_val(*pte));
  78                                 err = 1;
  79                         }
  80                         s->lpg++;
  81                         i += LPS/PAGE_SIZE;
  82                 } else {
  83                         s->spg++;
  84                         i++;
  85                 }
  86                 if (!(pte_val(*pte) & _PAGE_NX)) {
  87                         s->exec++;
  88                         if (addr < s->min_exec)
  89                                 s->min_exec = addr;
  90                         if (addr > s->max_exec)
  91                                 s->max_exec = addr;
  92                 }
  93         }
  94         if (print) {
  95                 printk(KERN_INFO
  96                         " 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,
  99                         s->max_exec, missed);
 100         }
 101
 102         expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
 103         if (expected != i) {
 104                 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
 105                         max_pfn_mapped, expected);
 106                 return 1;
 107         }
 108         return err;
 109 }
 110
 111 static unsigned long addr[NTEST];
 112 static unsigned int len[NTEST];
 113
 114 static struct page *pages[NPAGES];
 115 static unsigned long addrs[NPAGES];
 116
 117 /* Change the global bit on random pages in the direct mapping */
 118 static int pageattr_test(void)
 119 {
 120         struct split_state sa, sb, sc;
 121         unsigned long *bm;
 122         pte_t *pte, pte0;
 123         int failed = 0;
 124         unsigned int level;
 125         int i, k;
 126         int err;
 127
 128         if (print)
 129                 printk(KERN_INFO "CPA self-test:\n");
 130
 131         bm = vzalloc((max_pfn_mapped + 7) / 8);
 132         if (!bm) {
 133                 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 134                 return -ENOMEM;
 135         }
 136
 137         failed += print_split(&sa);
 138
 139         for (i = 0; i < NTEST; i++) {
 140                 unsigned long pfn = prandom_u32() % max_pfn_mapped;
 141
 142                 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 143                 len[i] = prandom_u32() % NPAGES;
 144                 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 145
 146                 if (len[i] == 0)
 147                         len[i] = 1;
 148
 149                 pte = NULL;
 150                 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 151
 152                 for (k = 0; k < len[i]; k++) {
 153                         pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 154                         if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
 155                             !(pte_val(*pte) & _PAGE_PRESENT)) {
 156                                 addr[i] = 0;
 157                                 break;
 158                         }
 159                         if (k == 0) {
 160                                 pte0 = *pte;
 161                         } else {
 162                                 if (pgprot_val(pte_pgprot(*pte)) !=
 163                                         pgprot_val(pte_pgprot(pte0))) {
 164                                         len[i] = k;
 165                                         break;
 166                                 }
 167                         }
 168                         if (test_bit(pfn + k, bm)) {
 169                                 len[i] = k;
 170                                 break;
 171                         }
 172                         __set_bit(pfn + k, bm);
 173                         addrs[k] = addr[i] + k*PAGE_SIZE;
 174                         pages[k] = pfn_to_page(pfn + k);
 175                 }
 176                 if (!addr[i] || !pte || !k) {
 177                         addr[i] = 0;
 178                         continue;
 179                 }
 180
 181                 switch (i % 3) {
 182                 case 0:
 183                         err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
 184                         break;
 185
 186                 case 1:
 187                         err = change_page_attr_set(addrs, len[1], PAGE_CPA_TEST, 1);
 188                         break;
 189
 190                 case 2:
 191                         err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
 192                         break;
 193                 }
 194
 195
 196                 if (err < 0) {
 197                         printk(KERN_ERR "CPA %d failed %d\n", i, err);
 198                         failed++;
 199                 }
 200
 201                 pte = lookup_address(addr[i], &level);
 202                 if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
 203                         printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 204                                 pte ? (u64)pte_val(*pte) : 0ULL);
 205                         failed++;
 206                 }
 207                 if (level != PG_LEVEL_4K) {
 208                         printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 209                                 addr[i], level);
 210                         failed++;
 211                 }
 212
 213         }
 214         vfree(bm);
 215
 216         failed += print_split(&sb);
 217
 218         for (i = 0; i < NTEST; i++) {
 219                 if (!addr[i])
 220                         continue;
 221                 pte = lookup_address(addr[i], &level);
 222                 if (!pte) {
 223                         printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 224                         failed++;
 225                         continue;
 226                 }
 227                 err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
 228                 if (err < 0) {
 229                         printk(KERN_ERR "CPA reverting failed: %d\n", err);
 230                         failed++;
 231                 }
 232                 pte = lookup_address(addr[i], &level);
 233                 if (!pte || pte_testbit(*pte)) {
 234                         printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 235                                 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 236                         failed++;
 237                 }
 238
 239         }
 240
 241         failed += print_split(&sc);
 242
 243         if (failed) {
 244                 WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
 245                 return -EINVAL;
 246         } else {
 247                 if (print)
 248                         printk(KERN_INFO "ok.\n");
 249         }
 250
 251         return 0;
 252 }
 253
 254 static int do_pageattr_test(void *__unused)
 255 {
 256         while (!kthread_should_stop()) {
 257                 schedule_timeout_interruptible(HZ*30);
 258                 if (pageattr_test() < 0)
 259                         break;
 260                 if (print)
 261                         print--;
 262         }
 263         return 0;
 264 }
 265
 266 static int start_pageattr_test(void)
 267 {
 268         struct task_struct *p;
 269
 270         p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
 271         if (!IS_ERR(p))
 272                 wake_up_process(p);
 273         else
 274                 WARN_ON(1);
 275
 276         return 0;
 277 }
 278 device_initcall(start_pageattr_test);