mm/debug_vm_pgtable.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This kernel test validates architecture page table helpers and
   4  * accessors and helps in verifying their continued compliance with
   5  * expected generic MM semantics.
   6  *
   7  * Copyright (C) 2019 ARM Ltd.
   8  *
   9  * Author: Anshuman Khandual <anshuman.khandual@arm.com>
  10  */
  11 #define pr_fmt(fmt) "debug_vm_pgtable: [%-25s]: " fmt, __func__
  12
  13 #include <linux/gfp.h>
  14 #include <linux/highmem.h>
  15 #include <linux/hugetlb.h>
  16 #include <linux/kernel.h>
  17 #include <linux/kconfig.h>
  18 #include <linux/mm.h>
  19 #include <linux/mman.h>
  20 #include <linux/mm_types.h>
  21 #include <linux/module.h>
  22 #include <linux/pfn_t.h>
  23 #include <linux/printk.h>
  24 #include <linux/pgtable.h>
  25 #include <linux/random.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/swap.h>
  28 #include <linux/swapops.h>
  29 #include <linux/start_kernel.h>
  30 #include <linux/sched/mm.h>
  31 #include <linux/io.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/tlbflush.h>
  34
  35 /*
  36  * Please refer Documentation/vm/arch_pgtable_helpers.rst for the semantics
  37  * expectations that are being validated here. All future changes in here
  38  * or the documentation need to be in sync.
  39  */
  40
  41 #define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC)
  42
  43 /*
  44  * On s390 platform, the lower 4 bits are used to identify given page table
  45  * entry type. But these bits might affect the ability to clear entries with
  46  * pxx_clear() because of how dynamic page table folding works on s390. So
  47  * while loading up the entries do not change the lower 4 bits. It does not
  48  * have affect any other platform. Also avoid the 62nd bit on ppc64 that is
  49  * used to mark a pte entry.
  50  */
  51 #define S390_SKIP_MASK          GENMASK(3, 0)
  52 #if __BITS_PER_LONG == 64
  53 #define PPC64_SKIP_MASK         GENMASK(62, 62)
  54 #else
  55 #define PPC64_SKIP_MASK         0x0
  56 #endif
  57 #define ARCH_SKIP_MASK (S390_SKIP_MASK | PPC64_SKIP_MASK)
  58 #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
  59 #define RANDOM_NZVALUE  GENMASK(7, 0)
  60
  61 static void __init pte_basic_tests(unsigned long pfn, int idx)
  62 {
  63         pgprot_t prot = protection_map[idx];
  64         pte_t pte = pfn_pte(pfn, prot);
  65         unsigned long val = idx, *ptr = &val;
  66
  67         pr_debug("Validating PTE basic (%pGv)\n", ptr);
  68
  69         /*
  70          * This test needs to be executed after the given page table entry
  71          * is created with pfn_pte() to make sure that protection_map[idx]
  72          * does not have the dirty bit enabled from the beginning. This is
  73          * important for platforms like arm64 where (!PTE_RDONLY) indicate
  74          * dirty bit being set.
  75          */
  76         WARN_ON(pte_dirty(pte_wrprotect(pte)));
  77
  78         WARN_ON(!pte_same(pte, pte));
  79         WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte))));
  80         WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte))));
  81         WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte))));
  82         WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte))));
  83         WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte))));
  84         WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte))));
  85         WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte))));
  86         WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte))));
  87 }
  88
  89 static void __init pte_advanced_tests(struct mm_struct *mm,
  90                                       struct vm_area_struct *vma, pte_t *ptep,
  91                                       unsigned long pfn, unsigned long vaddr,
  92                                       pgprot_t prot)
  93 {
  94         pte_t pte = pfn_pte(pfn, prot);
  95
  96         /*
  97          * Architectures optimize set_pte_at by avoiding TLB flush.
  98          * This requires set_pte_at to be not used to update an
  99          * existing pte entry. Clear pte before we do set_pte_at
 100          */
 101
 102         pr_debug("Validating PTE advanced\n");
 103         pte = pfn_pte(pfn, prot);
 104         set_pte_at(mm, vaddr, ptep, pte);
 105         ptep_set_wrprotect(mm, vaddr, ptep);
 106         pte = ptep_get(ptep);
 107         WARN_ON(pte_write(pte));
 108         ptep_get_and_clear(mm, vaddr, ptep);
 109         pte = ptep_get(ptep);
 110         WARN_ON(!pte_none(pte));
 111
 112         pte = pfn_pte(pfn, prot);
 113         pte = pte_wrprotect(pte);
 114         pte = pte_mkclean(pte);
 115         set_pte_at(mm, vaddr, ptep, pte);
 116         pte = pte_mkwrite(pte);
 117         pte = pte_mkdirty(pte);
 118         ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
 119         pte = ptep_get(ptep);
 120         WARN_ON(!(pte_write(pte) && pte_dirty(pte)));
 121         ptep_get_and_clear_full(mm, vaddr, ptep, 1);
 122         pte = ptep_get(ptep);
 123         WARN_ON(!pte_none(pte));
 124
 125         pte = pfn_pte(pfn, prot);
 126         pte = pte_mkyoung(pte);
 127         set_pte_at(mm, vaddr, ptep, pte);
 128         ptep_test_and_clear_young(vma, vaddr, ptep);
 129         pte = ptep_get(ptep);
 130         WARN_ON(pte_young(pte));
 131 }
 132
 133 static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 134 {
 135         pte_t pte = pfn_pte(pfn, prot);
 136
 137         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 138                 return;
 139
 140         pr_debug("Validating PTE saved write\n");
 141         WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
 142         WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
 143 }
 144
 145 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 146 static void __init pmd_basic_tests(unsigned long pfn, int idx)
 147 {
 148         pgprot_t prot = protection_map[idx];
 149         pmd_t pmd = pfn_pmd(pfn, prot);
 150         unsigned long val = idx, *ptr = &val;
 151
 152         if (!has_transparent_hugepage())
 153                 return;
 154
 155         pr_debug("Validating PMD basic (%pGv)\n", ptr);
 156
 157         /*
 158          * This test needs to be executed after the given page table entry
 159          * is created with pfn_pmd() to make sure that protection_map[idx]
 160          * does not have the dirty bit enabled from the beginning. This is
 161          * important for platforms like arm64 where (!PTE_RDONLY) indicate
 162          * dirty bit being set.
 163          */
 164         WARN_ON(pmd_dirty(pmd_wrprotect(pmd)));
 165
 166
 167         WARN_ON(!pmd_same(pmd, pmd));
 168         WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
 169         WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
 170         WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd))));
 171         WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd))));
 172         WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd))));
 173         WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd))));
 174         WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd))));
 175         WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd))));
 176         /*
 177          * A huge page does not point to next level page table
 178          * entry. Hence this must qualify as pmd_bad().
 179          */
 180         WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
 181 }
 182
 183 static void __init pmd_advanced_tests(struct mm_struct *mm,
 184                                       struct vm_area_struct *vma, pmd_t *pmdp,
 185                                       unsigned long pfn, unsigned long vaddr,
 186                                       pgprot_t prot, pgtable_t pgtable)
 187 {
 188         pmd_t pmd = pfn_pmd(pfn, prot);
 189
 190         if (!has_transparent_hugepage())
 191                 return;
 192
 193         pr_debug("Validating PMD advanced\n");
 194         /* Align the address wrt HPAGE_PMD_SIZE */
 195         vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
 196
 197         pgtable_trans_huge_deposit(mm, pmdp, pgtable);
 198
 199         pmd = pfn_pmd(pfn, prot);
 200         set_pmd_at(mm, vaddr, pmdp, pmd);
 201         pmdp_set_wrprotect(mm, vaddr, pmdp);
 202         pmd = READ_ONCE(*pmdp);
 203         WARN_ON(pmd_write(pmd));
 204         pmdp_huge_get_and_clear(mm, vaddr, pmdp);
 205         pmd = READ_ONCE(*pmdp);
 206         WARN_ON(!pmd_none(pmd));
 207
 208         pmd = pfn_pmd(pfn, prot);
 209         pmd = pmd_wrprotect(pmd);
 210         pmd = pmd_mkclean(pmd);
 211         set_pmd_at(mm, vaddr, pmdp, pmd);
 212         pmd = pmd_mkwrite(pmd);
 213         pmd = pmd_mkdirty(pmd);
 214         pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1);
 215         pmd = READ_ONCE(*pmdp);
 216         WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd)));
 217         pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1);
 218         pmd = READ_ONCE(*pmdp);
 219         WARN_ON(!pmd_none(pmd));
 220
 221         pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
 222         pmd = pmd_mkyoung(pmd);
 223         set_pmd_at(mm, vaddr, pmdp, pmd);
 224         pmdp_test_and_clear_young(vma, vaddr, pmdp);
 225         pmd = READ_ONCE(*pmdp);
 226         WARN_ON(pmd_young(pmd));
 227
 228         /*  Clear the pte entries  */
 229         pmdp_huge_get_and_clear(mm, vaddr, pmdp);
 230         pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
 231 }
 232
 233 static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
 234 {
 235         pmd_t pmd = pfn_pmd(pfn, prot);
 236
 237         pr_debug("Validating PMD leaf\n");
 238         /*
 239          * PMD based THP is a leaf entry.
 240          */
 241         pmd = pmd_mkhuge(pmd);
 242         WARN_ON(!pmd_leaf(pmd));
 243 }
 244
 245 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 246 static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
 247 {
 248         pmd_t pmd;
 249
 250         if (!arch_ioremap_pmd_supported())
 251                 return;
 252
 253         pr_debug("Validating PMD huge\n");
 254         /*
 255          * X86 defined pmd_set_huge() verifies that the given
 256          * PMD is not a populated non-leaf entry.
 257          */
 258         WRITE_ONCE(*pmdp, __pmd(0));
 259         WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot));
 260         WARN_ON(!pmd_clear_huge(pmdp));
 261         pmd = READ_ONCE(*pmdp);
 262         WARN_ON(!pmd_none(pmd));
 263 }
 264 #else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 265 static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { }
 266 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 267
 268 static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 269 {
 270         pmd_t pmd = pfn_pmd(pfn, prot);
 271
 272         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 273                 return;
 274
 275         pr_debug("Validating PMD saved write\n");
 276         WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
 277         WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
 278 }
 279
 280 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 281 static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
 282 {
 283         pgprot_t prot = protection_map[idx];
 284         pud_t pud = pfn_pud(pfn, prot);
 285         unsigned long val = idx, *ptr = &val;
 286
 287         if (!has_transparent_hugepage())
 288                 return;
 289
 290         pr_debug("Validating PUD basic (%pGv)\n", ptr);
 291
 292         /*
 293          * This test needs to be executed after the given page table entry
 294          * is created with pfn_pud() to make sure that protection_map[idx]
 295          * does not have the dirty bit enabled from the beginning. This is
 296          * important for platforms like arm64 where (!PTE_RDONLY) indicate
 297          * dirty bit being set.
 298          */
 299         WARN_ON(pud_dirty(pud_wrprotect(pud)));
 300
 301         WARN_ON(!pud_same(pud, pud));
 302         WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
 303         WARN_ON(!pud_dirty(pud_mkdirty(pud_mkclean(pud))));
 304         WARN_ON(pud_dirty(pud_mkclean(pud_mkdirty(pud))));
 305         WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud))));
 306         WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud))));
 307         WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud))));
 308         WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud))));
 309         WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud))));
 310
 311         if (mm_pmd_folded(mm))
 312                 return;
 313
 314         /*
 315          * A huge page does not point to next level page table
 316          * entry. Hence this must qualify as pud_bad().
 317          */
 318         WARN_ON(!pud_bad(pud_mkhuge(pud)));
 319 }
 320
 321 static void __init pud_advanced_tests(struct mm_struct *mm,
 322                                       struct vm_area_struct *vma, pud_t *pudp,
 323                                       unsigned long pfn, unsigned long vaddr,
 324                                       pgprot_t prot)
 325 {
 326         pud_t pud = pfn_pud(pfn, prot);
 327
 328         if (!has_transparent_hugepage())
 329                 return;
 330
 331         pr_debug("Validating PUD advanced\n");
 332         /* Align the address wrt HPAGE_PUD_SIZE */
 333         vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE;
 334
 335         set_pud_at(mm, vaddr, pudp, pud);
 336         pudp_set_wrprotect(mm, vaddr, pudp);
 337         pud = READ_ONCE(*pudp);
 338         WARN_ON(pud_write(pud));
 339
 340 #ifndef __PAGETABLE_PMD_FOLDED
 341         pudp_huge_get_and_clear(mm, vaddr, pudp);
 342         pud = READ_ONCE(*pudp);
 343         WARN_ON(!pud_none(pud));
 344 #endif /* __PAGETABLE_PMD_FOLDED */
 345         pud = pfn_pud(pfn, prot);
 346         pud = pud_wrprotect(pud);
 347         pud = pud_mkclean(pud);
 348         set_pud_at(mm, vaddr, pudp, pud);
 349         pud = pud_mkwrite(pud);
 350         pud = pud_mkdirty(pud);
 351         pudp_set_access_flags(vma, vaddr, pudp, pud, 1);
 352         pud = READ_ONCE(*pudp);
 353         WARN_ON(!(pud_write(pud) && pud_dirty(pud)));
 354
 355 #ifndef __PAGETABLE_PMD_FOLDED
 356         pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1);
 357         pud = READ_ONCE(*pudp);
 358         WARN_ON(!pud_none(pud));
 359 #endif /* __PAGETABLE_PMD_FOLDED */
 360
 361         pud = pfn_pud(pfn, prot);
 362         pud = pud_mkyoung(pud);
 363         set_pud_at(mm, vaddr, pudp, pud);
 364         pudp_test_and_clear_young(vma, vaddr, pudp);
 365         pud = READ_ONCE(*pudp);
 366         WARN_ON(pud_young(pud));
 367
 368         pudp_huge_get_and_clear(mm, vaddr, pudp);
 369 }
 370
 371 static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
 372 {
 373         pud_t pud = pfn_pud(pfn, prot);
 374
 375         pr_debug("Validating PUD leaf\n");
 376         /*
 377          * PUD based THP is a leaf entry.
 378          */
 379         pud = pud_mkhuge(pud);
 380         WARN_ON(!pud_leaf(pud));
 381 }
 382
 383 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 384 static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 385 {
 386         pud_t pud;
 387
 388         if (!arch_ioremap_pud_supported())
 389                 return;
 390
 391         pr_debug("Validating PUD huge\n");
 392         /*
 393          * X86 defined pud_set_huge() verifies that the given
 394          * PUD is not a populated non-leaf entry.
 395          */
 396         WRITE_ONCE(*pudp, __pud(0));
 397         WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
 398         WARN_ON(!pud_clear_huge(pudp));
 399         pud = READ_ONCE(*pudp);
 400         WARN_ON(!pud_none(pud));
 401 }
 402 #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 403 static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
 404 #endif /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 405
 406 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 407 static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx) { }
 408 static void __init pud_advanced_tests(struct mm_struct *mm,
 409                                       struct vm_area_struct *vma, pud_t *pudp,
 410                                       unsigned long pfn, unsigned long vaddr,
 411                                       pgprot_t prot)
 412 {
 413 }
 414 static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
 415 static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 416 {
 417 }
 418 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 419 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 420 static void __init pmd_basic_tests(unsigned long pfn, int idx) { }
 421 static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx) { }
 422 static void __init pmd_advanced_tests(struct mm_struct *mm,
 423                                       struct vm_area_struct *vma, pmd_t *pmdp,
 424                                       unsigned long pfn, unsigned long vaddr,
 425                                       pgprot_t prot, pgtable_t pgtable)
 426 {
 427 }
 428 static void __init pud_advanced_tests(struct mm_struct *mm,
 429                                       struct vm_area_struct *vma, pud_t *pudp,
 430                                       unsigned long pfn, unsigned long vaddr,
 431                                       pgprot_t prot)
 432 {
 433 }
 434 static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) { }
 435 static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
 436 static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
 437 {
 438 }
 439 static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 440 {
 441 }
 442 static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) { }
 443 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 444
 445 static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
 446 {
 447         p4d_t p4d;
 448
 449         pr_debug("Validating P4D basic\n");
 450         memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t));
 451         WARN_ON(!p4d_same(p4d, p4d));
 452 }
 453
 454 static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot)
 455 {
 456         pgd_t pgd;
 457
 458         pr_debug("Validating PGD basic\n");
 459         memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t));
 460         WARN_ON(!pgd_same(pgd, pgd));
 461 }
 462
 463 #ifndef __PAGETABLE_PUD_FOLDED
 464 static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp)
 465 {
 466         pud_t pud = READ_ONCE(*pudp);
 467
 468         if (mm_pmd_folded(mm))
 469                 return;
 470
 471         pr_debug("Validating PUD clear\n");
 472         pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
 473         WRITE_ONCE(*pudp, pud);
 474         pud_clear(pudp);
 475         pud = READ_ONCE(*pudp);
 476         WARN_ON(!pud_none(pud));
 477 }
 478
 479 static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
 480                                       pmd_t *pmdp)
 481 {
 482         pud_t pud;
 483
 484         if (mm_pmd_folded(mm))
 485                 return;
 486
 487         pr_debug("Validating PUD populate\n");
 488         /*
 489          * This entry points to next level page table page.
 490          * Hence this must not qualify as pud_bad().
 491          */
 492         pud_populate(mm, pudp, pmdp);
 493         pud = READ_ONCE(*pudp);
 494         WARN_ON(pud_bad(pud));
 495 }
 496 #else  /* !__PAGETABLE_PUD_FOLDED */
 497 static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { }
 498 static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
 499                                       pmd_t *pmdp)
 500 {
 501 }
 502 #endif /* PAGETABLE_PUD_FOLDED */
 503
 504 #ifndef __PAGETABLE_P4D_FOLDED
 505 static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp)
 506 {
 507         p4d_t p4d = READ_ONCE(*p4dp);
 508
 509         if (mm_pud_folded(mm))
 510                 return;
 511
 512         pr_debug("Validating P4D clear\n");
 513         p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
 514         WRITE_ONCE(*p4dp, p4d);
 515         p4d_clear(p4dp);
 516         p4d = READ_ONCE(*p4dp);
 517         WARN_ON(!p4d_none(p4d));
 518 }
 519
 520 static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
 521                                       pud_t *pudp)
 522 {
 523         p4d_t p4d;
 524
 525         if (mm_pud_folded(mm))
 526                 return;
 527
 528         pr_debug("Validating P4D populate\n");
 529         /*
 530          * This entry points to next level page table page.
 531          * Hence this must not qualify as p4d_bad().
 532          */
 533         pud_clear(pudp);
 534         p4d_clear(p4dp);
 535         p4d_populate(mm, p4dp, pudp);
 536         p4d = READ_ONCE(*p4dp);
 537         WARN_ON(p4d_bad(p4d));
 538 }
 539
 540 static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp)
 541 {
 542         pgd_t pgd = READ_ONCE(*pgdp);
 543
 544         if (mm_p4d_folded(mm))
 545                 return;
 546
 547         pr_debug("Validating PGD clear\n");
 548         pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE);
 549         WRITE_ONCE(*pgdp, pgd);
 550         pgd_clear(pgdp);
 551         pgd = READ_ONCE(*pgdp);
 552         WARN_ON(!pgd_none(pgd));
 553 }
 554
 555 static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
 556                                       p4d_t *p4dp)
 557 {
 558         pgd_t pgd;
 559
 560         if (mm_p4d_folded(mm))
 561                 return;
 562
 563         pr_debug("Validating PGD populate\n");
 564         /*
 565          * This entry points to next level page table page.
 566          * Hence this must not qualify as pgd_bad().
 567          */
 568         p4d_clear(p4dp);
 569         pgd_clear(pgdp);
 570         pgd_populate(mm, pgdp, p4dp);
 571         pgd = READ_ONCE(*pgdp);
 572         WARN_ON(pgd_bad(pgd));
 573 }
 574 #else  /* !__PAGETABLE_P4D_FOLDED */
 575 static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) { }
 576 static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { }
 577 static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
 578                                       pud_t *pudp)
 579 {
 580 }
 581 static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
 582                                       p4d_t *p4dp)
 583 {
 584 }
 585 #endif /* PAGETABLE_P4D_FOLDED */
 586
 587 static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,
 588                                    unsigned long pfn, unsigned long vaddr,
 589                                    pgprot_t prot)
 590 {
 591         pte_t pte = pfn_pte(pfn, prot);
 592
 593         pr_debug("Validating PTE clear\n");
 594 #ifndef CONFIG_RISCV
 595         pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 596 #endif
 597         set_pte_at(mm, vaddr, ptep, pte);
 598         barrier();
 599         pte_clear(mm, vaddr, ptep);
 600         pte = ptep_get(ptep);
 601         WARN_ON(!pte_none(pte));
 602 }
 603
 604 static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
 605 {
 606         pmd_t pmd = READ_ONCE(*pmdp);
 607
 608         pr_debug("Validating PMD clear\n");
 609         pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
 610         WRITE_ONCE(*pmdp, pmd);
 611         pmd_clear(pmdp);
 612         pmd = READ_ONCE(*pmdp);
 613         WARN_ON(!pmd_none(pmd));
 614 }
 615
 616 static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
 617                                       pgtable_t pgtable)
 618 {
 619         pmd_t pmd;
 620
 621         pr_debug("Validating PMD populate\n");
 622         /*
 623          * This entry points to next level page table page.
 624          * Hence this must not qualify as pmd_bad().
 625          */
 626         pmd_populate(mm, pmdp, pgtable);
 627         pmd = READ_ONCE(*pmdp);
 628         WARN_ON(pmd_bad(pmd));
 629 }
 630
 631 static void __init pte_special_tests(unsigned long pfn, pgprot_t prot)
 632 {
 633         pte_t pte = pfn_pte(pfn, prot);
 634
 635         if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL))
 636                 return;
 637
 638         pr_debug("Validating PTE special\n");
 639         WARN_ON(!pte_special(pte_mkspecial(pte)));
 640 }
 641
 642 static void __init pte_protnone_tests(unsigned long pfn, pgprot_t prot)
 643 {
 644         pte_t pte = pfn_pte(pfn, prot);
 645
 646         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 647                 return;
 648
 649         pr_debug("Validating PTE protnone\n");
 650         WARN_ON(!pte_protnone(pte));
 651         WARN_ON(!pte_present(pte));
 652 }
 653
 654 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 655 static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot)
 656 {
 657         pmd_t pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
 658
 659         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 660                 return;
 661
 662         pr_debug("Validating PMD protnone\n");
 663         WARN_ON(!pmd_protnone(pmd));
 664         WARN_ON(!pmd_present(pmd));
 665 }
 666 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 667 static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot) { }
 668 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 669
 670 #ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 671 static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot)
 672 {
 673         pte_t pte = pfn_pte(pfn, prot);
 674
 675         pr_debug("Validating PTE devmap\n");
 676         WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
 677 }
 678
 679 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 680 static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
 681 {
 682         pmd_t pmd = pfn_pmd(pfn, prot);
 683
 684         pr_debug("Validating PMD devmap\n");
 685         WARN_ON(!pmd_devmap(pmd_mkdevmap(pmd)));
 686 }
 687
 688 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 689 static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot)
 690 {
 691         pud_t pud = pfn_pud(pfn, prot);
 692
 693         pr_debug("Validating PUD devmap\n");
 694         WARN_ON(!pud_devmap(pud_mkdevmap(pud)));
 695 }
 696 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 697 static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 698 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 699 #else  /* CONFIG_TRANSPARENT_HUGEPAGE */
 700 static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 701 static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 702 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 703 #else
 704 static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 705 static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 706 static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
 707 #endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 708
 709 static void __init pte_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 710 {
 711         pte_t pte = pfn_pte(pfn, prot);
 712
 713         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 714                 return;
 715
 716         pr_debug("Validating PTE soft dirty\n");
 717         WARN_ON(!pte_soft_dirty(pte_mksoft_dirty(pte)));
 718         WARN_ON(pte_soft_dirty(pte_clear_soft_dirty(pte)));
 719 }
 720
 721 static void __init pte_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 722 {
 723         pte_t pte = pfn_pte(pfn, prot);
 724
 725         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 726                 return;
 727
 728         pr_debug("Validating PTE swap soft dirty\n");
 729         WARN_ON(!pte_swp_soft_dirty(pte_swp_mksoft_dirty(pte)));
 730         WARN_ON(pte_swp_soft_dirty(pte_swp_clear_soft_dirty(pte)));
 731 }
 732
 733 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 734 static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 735 {
 736         pmd_t pmd = pfn_pmd(pfn, prot);
 737
 738         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 739                 return;
 740
 741         pr_debug("Validating PMD soft dirty\n");
 742         WARN_ON(!pmd_soft_dirty(pmd_mksoft_dirty(pmd)));
 743         WARN_ON(pmd_soft_dirty(pmd_clear_soft_dirty(pmd)));
 744 }
 745
 746 static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 747 {
 748         pmd_t pmd = pfn_pmd(pfn, prot);
 749
 750         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
 751                 !IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
 752                 return;
 753
 754         pr_debug("Validating PMD swap soft dirty\n");
 755         WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd)));
 756         WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd)));
 757 }
 758 #else  /* !CONFIG_ARCH_HAS_PTE_DEVMAP */
 759 static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot) { }
 760 static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 761 {
 762 }
 763 #endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 764
 765 static void __init pte_swap_tests(unsigned long pfn, pgprot_t prot)
 766 {
 767         swp_entry_t swp;
 768         pte_t pte;
 769
 770         pr_debug("Validating PTE swap\n");
 771         pte = pfn_pte(pfn, prot);
 772         swp = __pte_to_swp_entry(pte);
 773         pte = __swp_entry_to_pte(swp);
 774         WARN_ON(pfn != pte_pfn(pte));
 775 }
 776
 777 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 778 static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot)
 779 {
 780         swp_entry_t swp;
 781         pmd_t pmd;
 782
 783         pr_debug("Validating PMD swap\n");
 784         pmd = pfn_pmd(pfn, prot);
 785         swp = __pmd_to_swp_entry(pmd);
 786         pmd = __swp_entry_to_pmd(swp);
 787         WARN_ON(pfn != pmd_pfn(pmd));
 788 }
 789 #else  /* !CONFIG_ARCH_ENABLE_THP_MIGRATION */
 790 static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot) { }
 791 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 792
 793 static void __init swap_migration_tests(void)
 794 {
 795         struct page *page;
 796         swp_entry_t swp;
 797
 798         if (!IS_ENABLED(CONFIG_MIGRATION))
 799                 return;
 800
 801         pr_debug("Validating swap migration\n");
 802         /*
 803          * swap_migration_tests() requires a dedicated page as it needs to
 804          * be locked before creating a migration entry from it. Locking the
 805          * page that actually maps kernel text ('start_kernel') can be real
 806          * problematic. Lets allocate a dedicated page explicitly for this
 807          * purpose that will be freed subsequently.
 808          */
 809         page = alloc_page(GFP_KERNEL);
 810         if (!page) {
 811                 pr_err("page allocation failed\n");
 812                 return;
 813         }
 814
 815         /*
 816          * make_migration_entry() expects given page to be
 817          * locked, otherwise it stumbles upon a BUG_ON().
 818          */
 819         __SetPageLocked(page);
 820         swp = make_migration_entry(page, 1);
 821         WARN_ON(!is_migration_entry(swp));
 822         WARN_ON(!is_write_migration_entry(swp));
 823
 824         make_migration_entry_read(&swp);
 825         WARN_ON(!is_migration_entry(swp));
 826         WARN_ON(is_write_migration_entry(swp));
 827
 828         swp = make_migration_entry(page, 0);
 829         WARN_ON(!is_migration_entry(swp));
 830         WARN_ON(is_write_migration_entry(swp));
 831         __ClearPageLocked(page);
 832         __free_page(page);
 833 }
 834
 835 #ifdef CONFIG_HUGETLB_PAGE
 836 static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot)
 837 {
 838         struct page *page;
 839         pte_t pte;
 840
 841         pr_debug("Validating HugeTLB basic\n");
 842         /*
 843          * Accessing the page associated with the pfn is safe here,
 844          * as it was previously derived from a real kernel symbol.
 845          */
 846         page = pfn_to_page(pfn);
 847         pte = mk_huge_pte(page, prot);
 848
 849         WARN_ON(!huge_pte_dirty(huge_pte_mkdirty(pte)));
 850         WARN_ON(!huge_pte_write(huge_pte_mkwrite(huge_pte_wrprotect(pte))));
 851         WARN_ON(huge_pte_write(huge_pte_wrprotect(huge_pte_mkwrite(pte))));
 852
 853 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
 854         pte = pfn_pte(pfn, prot);
 855
 856         WARN_ON(!pte_huge(pte_mkhuge(pte)));
 857 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
 858 }
 859 #else  /* !CONFIG_HUGETLB_PAGE */
 860 static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot) { }
 861 #endif /* CONFIG_HUGETLB_PAGE */
 862
 863 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 864 static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
 865 {
 866         pmd_t pmd;
 867
 868         if (!has_transparent_hugepage())
 869                 return;
 870
 871         pr_debug("Validating PMD based THP\n");
 872         /*
 873          * pmd_trans_huge() and pmd_present() must return positive after
 874          * MMU invalidation with pmd_mkinvalid(). This behavior is an
 875          * optimization for transparent huge page. pmd_trans_huge() must
 876          * be true if pmd_page() returns a valid THP to avoid taking the
 877          * pmd_lock when others walk over non transhuge pmds (i.e. there
 878          * are no THP allocated). Especially when splitting a THP and
 879          * removing the present bit from the pmd, pmd_trans_huge() still
 880          * needs to return true. pmd_present() should be true whenever
 881          * pmd_trans_huge() returns true.
 882          */
 883         pmd = pfn_pmd(pfn, prot);
 884         WARN_ON(!pmd_trans_huge(pmd_mkhuge(pmd)));
 885
 886 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 887         WARN_ON(!pmd_trans_huge(pmd_mkinvalid(pmd_mkhuge(pmd))));
 888         WARN_ON(!pmd_present(pmd_mkinvalid(pmd_mkhuge(pmd))));
 889 #endif /* __HAVE_ARCH_PMDP_INVALIDATE */
 890 }
 891
 892 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 893 static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
 894 {
 895         pud_t pud;
 896
 897         if (!has_transparent_hugepage())
 898                 return;
 899
 900         pr_debug("Validating PUD based THP\n");
 901         pud = pfn_pud(pfn, prot);
 902         WARN_ON(!pud_trans_huge(pud_mkhuge(pud)));
 903
 904         /*
 905          * pud_mkinvalid() has been dropped for now. Enable back
 906          * these tests when it comes back with a modified pud_present().
 907          *
 908          * WARN_ON(!pud_trans_huge(pud_mkinvalid(pud_mkhuge(pud))));
 909          * WARN_ON(!pud_present(pud_mkinvalid(pud_mkhuge(pud))));
 910          */
 911 }
 912 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 913 static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
 914 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 915 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 916 static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot) { }
 917 static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
 918 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 919
 920 static unsigned long __init get_random_vaddr(void)
 921 {
 922         unsigned long random_vaddr, random_pages, total_user_pages;
 923
 924         total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE;
 925
 926         random_pages = get_random_long() % total_user_pages;
 927         random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE;
 928
 929         return random_vaddr;
 930 }
 931
 932 static int __init debug_vm_pgtable(void)
 933 {
 934         struct vm_area_struct *vma;
 935         struct mm_struct *mm;
 936         pgd_t *pgdp;
 937         p4d_t *p4dp, *saved_p4dp;
 938         pud_t *pudp, *saved_pudp;
 939         pmd_t *pmdp, *saved_pmdp, pmd;
 940         pte_t *ptep;
 941         pgtable_t saved_ptep;
 942         pgprot_t prot, protnone;
 943         phys_addr_t paddr;
 944         unsigned long vaddr, pte_aligned, pmd_aligned;
 945         unsigned long pud_aligned, p4d_aligned, pgd_aligned;
 946         spinlock_t *ptl = NULL;
 947         int idx;
 948
 949         pr_info("Validating architecture page table helpers\n");
 950         prot = vm_get_page_prot(VMFLAGS);
 951         vaddr = get_random_vaddr();
 952         mm = mm_alloc();
 953         if (!mm) {
 954                 pr_err("mm_struct allocation failed\n");
 955                 return 1;
 956         }
 957
 958         /*
 959          * __P000 (or even __S000) will help create page table entries with
 960          * PROT_NONE permission as required for pxx_protnone_tests().
 961          */
 962         protnone = __P000;
 963
 964         vma = vm_area_alloc(mm);
 965         if (!vma) {
 966                 pr_err("vma allocation failed\n");
 967                 return 1;
 968         }
 969
 970         /*
 971          * PFN for mapping at PTE level is determined from a standard kernel
 972          * text symbol. But pfns for higher page table levels are derived by
 973          * masking lower bits of this real pfn. These derived pfns might not
 974          * exist on the platform but that does not really matter as pfn_pxx()
 975          * helpers will still create appropriate entries for the test. This
 976          * helps avoid large memory block allocations to be used for mapping
 977          * at higher page table levels.
 978          */
 979         paddr = __pa_symbol(&start_kernel);
 980
 981         pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT;
 982         pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
 983         pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
 984         p4d_aligned = (paddr & P4D_MASK) >> PAGE_SHIFT;
 985         pgd_aligned = (paddr & PGDIR_MASK) >> PAGE_SHIFT;
 986         WARN_ON(!pfn_valid(pte_aligned));
 987
 988         pgdp = pgd_offset(mm, vaddr);
 989         p4dp = p4d_alloc(mm, pgdp, vaddr);
 990         pudp = pud_alloc(mm, p4dp, vaddr);
 991         pmdp = pmd_alloc(mm, pudp, vaddr);
 992         /*
 993          * Allocate pgtable_t
 994          */
 995         if (pte_alloc(mm, pmdp)) {
 996                 pr_err("pgtable allocation failed\n");
 997                 return 1;
 998         }
 999
1000         /*
1001          * Save all the page table page addresses as the page table
1002          * entries will be used for testing with random or garbage
1003          * values. These saved addresses will be used for freeing
1004          * page table pages.
1005          */
1006         pmd = READ_ONCE(*pmdp);
1007         saved_p4dp = p4d_offset(pgdp, 0UL);
1008         saved_pudp = pud_offset(p4dp, 0UL);
1009         saved_pmdp = pmd_offset(pudp, 0UL);
1010         saved_ptep = pmd_pgtable(pmd);
1011
1012         /*
1013          * Iterate over the protection_map[] to make sure that all
1014          * the basic page table transformation validations just hold
1015          * true irrespective of the starting protection value for a
1016          * given page table entry.
1017          */
1018         for (idx = 0; idx < ARRAY_SIZE(protection_map); idx++) {
1019                 pte_basic_tests(pte_aligned, idx);
1020                 pmd_basic_tests(pmd_aligned, idx);
1021                 pud_basic_tests(mm, pud_aligned, idx);
1022         }
1023
1024         /*
1025          * Both P4D and PGD level tests are very basic which do not
1026          * involve creating page table entries from the protection
1027          * value and the given pfn. Hence just keep them out from
1028          * the above iteration for now to save some test execution
1029          * time.
1030          */
1031         p4d_basic_tests(p4d_aligned, prot);
1032         pgd_basic_tests(pgd_aligned, prot);
1033
1034         pmd_leaf_tests(pmd_aligned, prot);
1035         pud_leaf_tests(pud_aligned, prot);
1036
1037         pte_savedwrite_tests(pte_aligned, protnone);
1038         pmd_savedwrite_tests(pmd_aligned, protnone);
1039
1040         pte_special_tests(pte_aligned, prot);
1041         pte_protnone_tests(pte_aligned, protnone);
1042         pmd_protnone_tests(pmd_aligned, protnone);
1043
1044         pte_devmap_tests(pte_aligned, prot);
1045         pmd_devmap_tests(pmd_aligned, prot);
1046         pud_devmap_tests(pud_aligned, prot);
1047
1048         pte_soft_dirty_tests(pte_aligned, prot);
1049         pmd_soft_dirty_tests(pmd_aligned, prot);
1050         pte_swap_soft_dirty_tests(pte_aligned, prot);
1051         pmd_swap_soft_dirty_tests(pmd_aligned, prot);
1052
1053         pte_swap_tests(pte_aligned, prot);
1054         pmd_swap_tests(pmd_aligned, prot);
1055
1056         swap_migration_tests();
1057
1058         pmd_thp_tests(pmd_aligned, prot);
1059         pud_thp_tests(pud_aligned, prot);
1060
1061         hugetlb_basic_tests(pte_aligned, prot);
1062
1063         /*
1064          * Page table modifying tests. They need to hold
1065          * proper page table lock.
1066          */
1067
1068         ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
1069         pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
1070         pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
1071         pte_unmap_unlock(ptep, ptl);
1072
1073         ptl = pmd_lock(mm, pmdp);
1074         pmd_clear_tests(mm, pmdp);
1075         pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
1076         pmd_huge_tests(pmdp, pmd_aligned, prot);
1077         pmd_populate_tests(mm, pmdp, saved_ptep);
1078         spin_unlock(ptl);
1079
1080         ptl = pud_lock(mm, pudp);
1081         pud_clear_tests(mm, pudp);
1082         pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
1083         pud_huge_tests(pudp, pud_aligned, prot);
1084         pud_populate_tests(mm, pudp, saved_pmdp);
1085         spin_unlock(ptl);
1086
1087         spin_lock(&mm->page_table_lock);
1088         p4d_clear_tests(mm, p4dp);
1089         pgd_clear_tests(mm, pgdp);
1090         p4d_populate_tests(mm, p4dp, saved_pudp);
1091         pgd_populate_tests(mm, pgdp, saved_p4dp);
1092         spin_unlock(&mm->page_table_lock);
1093
1094         p4d_free(mm, saved_p4dp);
1095         pud_free(mm, saved_pudp);
1096         pmd_free(mm, saved_pmdp);
1097         pte_free(mm, saved_ptep);
1098
1099         vm_area_free(vma);
1100         mm_dec_nr_puds(mm);
1101         mm_dec_nr_pmds(mm);
1102         mm_dec_nr_ptes(mm);
1103         mmdrop(mm);
1104         return 0;
1105 }
1106 late_initcall(debug_vm_pgtable);