// 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> #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_HUGEPAGEstatic void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot){	pmd_t pmd = pfn_pmd(pfn, prot); 	if (!has_transparent_hugepage())		return; 	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_PUDstatic void __init pud_basic_tests(unsigned long pfn, pgprot_t prot){	pud_t pud = pfn_pud(pfn, prot); 	if (!has_transparent_hugepage())		return; 	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_FOLDEDstatic 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_FOLDEDstatic 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 = ptep_get(ptep); 	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);	set_pte_at(mm, vaddr, ptep, pte);	barrier();	pte_clear(mm, vaddr, ptep);	pte = ptep_get(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);