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