| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * This kernel test validates architecture page table helpers and |
| * accessors and helps in verifying their continued compliance with |
| * expected generic MM semantics. |
| * |
| * Copyright (C) 2019 ARM Ltd. |
| * |
| * Author: Anshuman Khandual <anshuman.khandual@arm.com> |
| */ |
| #define pr_fmt(fmt) "debug_vm_pgtable: %s: " fmt, __func__ |
| |
| #include <linux/gfp.h> |
| #include <linux/highmem.h> |
| #include <linux/hugetlb.h> |
| #include <linux/kernel.h> |
| #include <linux/kconfig.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/mm_types.h> |
| #include <linux/module.h> |
| #include <linux/pfn_t.h> |
| #include <linux/printk.h> |
| #include <linux/random.h> |
| #include <linux/spinlock.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/start_kernel.h> |
| #include <linux/sched/mm.h> |
| #include <asm/pgalloc.h> |
| #include <asm/pgtable.h> |
| |
| #define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC) |
| |
| /* |
| * On s390 platform, the lower 4 bits are used to identify given page table |
| * entry type. But these bits might affect the ability to clear entries with |
| * pxx_clear() because of how dynamic page table folding works on s390. So |
| * while loading up the entries do not change the lower 4 bits. It does not |
| * have affect any other platform. |
| */ |
| #define S390_MASK_BITS 4 |
| #define RANDOM_ORVALUE GENMASK(BITS_PER_LONG - 1, S390_MASK_BITS) |
| #define RANDOM_NZVALUE GENMASK(7, 0) |
| |
| static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) |
| { |
| pte_t pte = pfn_pte(pfn, prot); |
| |
| WARN_ON(!pte_same(pte, pte)); |
| WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte)))); |
| WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte)))); |
| WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte)))); |
| WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte)))); |
| WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte)))); |
| WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte)))); |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) |
| { |
| pmd_t pmd = pfn_pmd(pfn, prot); |
| |
| WARN_ON(!pmd_same(pmd, pmd)); |
| WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd)))); |
| WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd)))); |
| WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd)))); |
| WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd)))); |
| WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd)))); |
| WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd)))); |
| /* |
| * A huge page does not point to next level page table |
| * entry. Hence this must qualify as pmd_bad(). |
| */ |
| WARN_ON(!pmd_bad(pmd_mkhuge(pmd))); |
| } |
| |
| #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD |
| static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) |
| { |
| pud_t pud = pfn_pud(pfn, prot); |
| |
| WARN_ON(!pud_same(pud, pud)); |
| WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud)))); |
| WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud)))); |
| WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud)))); |
| WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud)))); |
| |
| if (mm_pmd_folded(mm)) |
| return; |
| |
| /* |
| * A huge page does not point to next level page table |
| * entry. Hence this must qualify as pud_bad(). |
| */ |
| WARN_ON(!pud_bad(pud_mkhuge(pud))); |
| } |
| #else /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
| static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } |
| #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ |
| #else /* !CONFIG_TRANSPARENT_HUGEPAGE */ |
| static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { } |
| static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
| |
| static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot) |
| { |
| p4d_t p4d; |
| |
| memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t)); |
| WARN_ON(!p4d_same(p4d, p4d)); |
| } |
| |
| static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot) |
| { |
| pgd_t pgd; |
| |
| memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t)); |
| WARN_ON(!pgd_same(pgd, pgd)); |
| } |
| |
| #ifndef __PAGETABLE_PUD_FOLDED |
| static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) |
| { |
| pud_t pud = READ_ONCE(*pudp); |
| |
| if (mm_pmd_folded(mm)) |
| return; |
| |
| pud = __pud(pud_val(pud) | RANDOM_ORVALUE); |
| WRITE_ONCE(*pudp, pud); |
| pud_clear(pudp); |
| pud = READ_ONCE(*pudp); |
| WARN_ON(!pud_none(pud)); |
| } |
| |
| static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, |
| pmd_t *pmdp) |
| { |
| pud_t pud; |
| |
| if (mm_pmd_folded(mm)) |
| return; |
| /* |
| * This entry points to next level page table page. |
| * Hence this must not qualify as pud_bad(). |
| */ |
| pmd_clear(pmdp); |
| pud_clear(pudp); |
| pud_populate(mm, pudp, pmdp); |
| pud = READ_ONCE(*pudp); |
| WARN_ON(pud_bad(pud)); |
| } |
| #else /* !__PAGETABLE_PUD_FOLDED */ |
| static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { } |
| static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, |
| pmd_t *pmdp) |
| { |
| } |
| #endif /* PAGETABLE_PUD_FOLDED */ |
| |
| #ifndef __PAGETABLE_P4D_FOLDED |
| static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) |
| { |
| p4d_t p4d = READ_ONCE(*p4dp); |
| |
| if (mm_pud_folded(mm)) |
| return; |
| |
| p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE); |
| WRITE_ONCE(*p4dp, p4d); |
| p4d_clear(p4dp); |
| p4d = READ_ONCE(*p4dp); |
| WARN_ON(!p4d_none(p4d)); |
| } |
| |
| static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, |
| pud_t *pudp) |
| { |
| p4d_t p4d; |
| |
| if (mm_pud_folded(mm)) |
| return; |
| |
| /* |
| * This entry points to next level page table page. |
| * Hence this must not qualify as p4d_bad(). |
| */ |
| pud_clear(pudp); |
| p4d_clear(p4dp); |
| p4d_populate(mm, p4dp, pudp); |
| p4d = READ_ONCE(*p4dp); |
| WARN_ON(p4d_bad(p4d)); |
| } |
| |
| static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) |
| { |
| pgd_t pgd = READ_ONCE(*pgdp); |
| |
| if (mm_p4d_folded(mm)) |
| return; |
| |
| pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE); |
| WRITE_ONCE(*pgdp, pgd); |
| pgd_clear(pgdp); |
| pgd = READ_ONCE(*pgdp); |
| WARN_ON(!pgd_none(pgd)); |
| } |
| |
| static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, |
| p4d_t *p4dp) |
| { |
| pgd_t pgd; |
| |
| if (mm_p4d_folded(mm)) |
| return; |
| |
| /* |
| * This entry points to next level page table page. |
| * Hence this must not qualify as pgd_bad(). |
| */ |
| p4d_clear(p4dp); |
| pgd_clear(pgdp); |
| pgd_populate(mm, pgdp, p4dp); |
| pgd = READ_ONCE(*pgdp); |
| WARN_ON(pgd_bad(pgd)); |
| } |
| #else /* !__PAGETABLE_P4D_FOLDED */ |
| static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) { } |
| static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { } |
| static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, |
| pud_t *pudp) |
| { |
| } |
| static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, |
| p4d_t *p4dp) |
| { |
| } |
| #endif /* PAGETABLE_P4D_FOLDED */ |
| |
| static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep, |
| unsigned long vaddr) |
| { |
| pte_t pte = READ_ONCE(*ptep); |
| |
| pte = __pte(pte_val(pte) | RANDOM_ORVALUE); |
| set_pte_at(mm, vaddr, ptep, pte); |
| barrier(); |
| pte_clear(mm, vaddr, ptep); |
| pte = READ_ONCE(*ptep); |
| WARN_ON(!pte_none(pte)); |
| } |
| |
| static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp) |
| { |
| pmd_t pmd = READ_ONCE(*pmdp); |
| |
| pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE); |
| WRITE_ONCE(*pmdp, pmd); |
| pmd_clear(pmdp); |
| pmd = READ_ONCE(*pmdp); |
| WARN_ON(!pmd_none(pmd)); |
| } |
| |
| static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp, |
| pgtable_t pgtable) |
| { |
| pmd_t pmd; |
| |
| /* |
| * This entry points to next level page table page. |
| * Hence this must not qualify as pmd_bad(). |
| */ |
| pmd_clear(pmdp); |
| pmd_populate(mm, pmdp, pgtable); |
| pmd = READ_ONCE(*pmdp); |
| WARN_ON(pmd_bad(pmd)); |
| } |
| |
| static unsigned long __init get_random_vaddr(void) |
| { |
| unsigned long random_vaddr, random_pages, total_user_pages; |
| |
| total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE; |
| |
| random_pages = get_random_long() % total_user_pages; |
| random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE; |
| |
| return random_vaddr; |
| } |
| |
| static int __init debug_vm_pgtable(void) |
| { |
| struct mm_struct *mm; |
| pgd_t *pgdp; |
| p4d_t *p4dp, *saved_p4dp; |
| pud_t *pudp, *saved_pudp; |
| pmd_t *pmdp, *saved_pmdp, pmd; |
| pte_t *ptep; |
| pgtable_t saved_ptep; |
| pgprot_t prot; |
| phys_addr_t paddr; |
| unsigned long vaddr, pte_aligned, pmd_aligned; |
| unsigned long pud_aligned, p4d_aligned, pgd_aligned; |
| spinlock_t *uninitialized_var(ptl); |
| |
| pr_info("Validating architecture page table helpers\n"); |
| prot = vm_get_page_prot(VMFLAGS); |
| vaddr = get_random_vaddr(); |
| mm = mm_alloc(); |
| if (!mm) { |
| pr_err("mm_struct allocation failed\n"); |
| return 1; |
| } |
| |
| /* |
| * PFN for mapping at PTE level is determined from a standard kernel |
| * text symbol. But pfns for higher page table levels are derived by |
| * masking lower bits of this real pfn. These derived pfns might not |
| * exist on the platform but that does not really matter as pfn_pxx() |
| * helpers will still create appropriate entries for the test. This |
| * helps avoid large memory block allocations to be used for mapping |
| * at higher page table levels. |
| */ |
| paddr = __pa_symbol(&start_kernel); |
| |
| pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT; |
| pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT; |
| pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT; |
| p4d_aligned = (paddr & P4D_MASK) >> PAGE_SHIFT; |
| pgd_aligned = (paddr & PGDIR_MASK) >> PAGE_SHIFT; |
| WARN_ON(!pfn_valid(pte_aligned)); |
| |
| pgdp = pgd_offset(mm, vaddr); |
| p4dp = p4d_alloc(mm, pgdp, vaddr); |
| pudp = pud_alloc(mm, p4dp, vaddr); |
| pmdp = pmd_alloc(mm, pudp, vaddr); |
| ptep = pte_alloc_map_lock(mm, pmdp, vaddr, &ptl); |
| |
| /* |
| * Save all the page table page addresses as the page table |
| * entries will be used for testing with random or garbage |
| * values. These saved addresses will be used for freeing |
| * page table pages. |
| */ |
| pmd = READ_ONCE(*pmdp); |
| saved_p4dp = p4d_offset(pgdp, 0UL); |
| saved_pudp = pud_offset(p4dp, 0UL); |
| saved_pmdp = pmd_offset(pudp, 0UL); |
| saved_ptep = pmd_pgtable(pmd); |
| |
| pte_basic_tests(pte_aligned, prot); |
| pmd_basic_tests(pmd_aligned, prot); |
| pud_basic_tests(pud_aligned, prot); |
| p4d_basic_tests(p4d_aligned, prot); |
| pgd_basic_tests(pgd_aligned, prot); |
| |
| pte_clear_tests(mm, ptep, vaddr); |
| pmd_clear_tests(mm, pmdp); |
| pud_clear_tests(mm, pudp); |
| p4d_clear_tests(mm, p4dp); |
| pgd_clear_tests(mm, pgdp); |
| |
| pte_unmap_unlock(ptep, ptl); |
| |
| pmd_populate_tests(mm, pmdp, saved_ptep); |
| pud_populate_tests(mm, pudp, saved_pmdp); |
| p4d_populate_tests(mm, p4dp, saved_pudp); |
| pgd_populate_tests(mm, pgdp, saved_p4dp); |
| |
| p4d_free(mm, saved_p4dp); |
| pud_free(mm, saved_pudp); |
| pmd_free(mm, saved_pmdp); |
| pte_free(mm, saved_ptep); |
| |
| mm_dec_nr_puds(mm); |
| mm_dec_nr_pmds(mm); |
| mm_dec_nr_ptes(mm); |
| mmdrop(mm); |
| return 0; |
| } |
| late_initcall(debug_vm_pgtable); |