From mboxrd@z Thu Jan 1 00:00:00 1970 From: christophe.leroy@c-s.fr (Christophe Leroy) Date: Thu, 12 Sep 2019 19:14:37 +0200 Subject: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers In-Reply-To: <1568268173-31302-3-git-send-email-anshuman.khandual@arm.com> References: <1568268173-31302-1-git-send-email-anshuman.khandual@arm.com> <1568268173-31302-3-git-send-email-anshuman.khandual@arm.com> List-ID: Message-ID: To: linux-snps-arc@lists.infradead.org Le 12/09/2019 ? 08:02, Anshuman Khandual a ?crit?: > This adds a test module which will validate architecture page table helpers > and accessors regarding compliance with generic MM semantics expectations. > This will help various architectures in validating changes to the existing > page table helpers or addition of new ones. > > Test page table and memory pages creating it's entries at various level are > all allocated from system memory with required alignments. If memory pages > with required size and alignment could not be allocated, then all depending > individual tests are skipped. > [...] > > Suggested-by: Catalin Marinas > Signed-off-by: Anshuman Khandual > --- > arch/x86/include/asm/pgtable_64_types.h | 2 + > mm/Kconfig.debug | 14 + > mm/Makefile | 1 + > mm/arch_pgtable_test.c | 429 ++++++++++++++++++++++++ > 4 files changed, 446 insertions(+) > create mode 100644 mm/arch_pgtable_test.c > > diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h > index 52e5f5f2240d..b882792a3999 100644 > --- a/arch/x86/include/asm/pgtable_64_types.h > +++ b/arch/x86/include/asm/pgtable_64_types.h > @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void) > #define pgtable_l5_enabled() 0 > #endif /* CONFIG_X86_5LEVEL */ > > +#define mm_p4d_folded(mm) (!pgtable_l5_enabled()) > + This is specific to x86, should go in a separate patch. > extern unsigned int pgdir_shift; > extern unsigned int ptrs_per_p4d; > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 327b3ebf23bf..ce9c397f7b07 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -117,3 +117,17 @@ config DEBUG_RODATA_TEST > depends on STRICT_KERNEL_RWX > ---help--- > This option enables a testcase for the setting rodata read-only. > + > +config DEBUG_ARCH_PGTABLE_TEST > + bool "Test arch page table helpers for semantics compliance" > + depends on MMU > + depends on DEBUG_KERNEL > + help > + This options provides a kernel module which can be used to test > + architecture page table helper functions on various platform in > + verifying if they comply with expected generic MM semantics. This > + will help architectures code in making sure that any changes or > + new additions of these helpers will still conform to generic MM > + expected semantics. > + > + If unsure, say N. > diff --git a/mm/Makefile b/mm/Makefile > index d996846697ef..bb572c5aa8c5 100644 > --- a/mm/Makefile > +++ b/mm/Makefile > @@ -86,6 +86,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o > obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o > obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o > obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o > +obj-$(CONFIG_DEBUG_ARCH_PGTABLE_TEST) += arch_pgtable_test.o > obj-$(CONFIG_PAGE_OWNER) += page_owner.o > obj-$(CONFIG_CLEANCACHE) += cleancache.o > obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o > diff --git a/mm/arch_pgtable_test.c b/mm/arch_pgtable_test.c > new file mode 100644 > index 000000000000..8b4a92756ad8 > --- /dev/null > +++ b/mm/arch_pgtable_test.c > @@ -0,0 +1,429 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * This kernel module validates architecture page table helpers & > + * accessors and helps in verifying their continued compliance with > + * generic MM semantics. > + * > + * Copyright (C) 2019 ARM Ltd. > + * > + * Author: Anshuman Khandual > + */ > +#define pr_fmt(fmt) "arch_pgtable_test: %s " fmt, __func__ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include Add (see other mails, build failure on ppc book3s/32) > +#include > +#include > + > +/* > + * Basic operations > + * > + * mkold(entry) = An old and not a young entry > + * mkyoung(entry) = A young and not an old entry > + * mkdirty(entry) = A dirty and not a clean entry > + * mkclean(entry) = A clean and not a dirty entry > + * mkwrite(entry) = A write and not a write protected entry > + * wrprotect(entry) = A write protected and not a write entry > + * pxx_bad(entry) = A mapped and non-table entry > + * pxx_same(entry1, entry2) = Both entries hold the exact same value > + */ > +#define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC) > + > +/* > + * On s390 platform, the lower 12 bits are used to identify given page table > + * entry type and for other arch specific requirements. But these bits might > + * affect the ability to clear entries with pxx_clear(). So while loading up > + * the entries skip all lower 12 bits in order to accommodate s390 platform. > + * It does not have affect any other platform. > + */ > +#define RANDOM_ORVALUE (0xfffffffffffff000UL) > +#define RANDOM_NZVALUE (0xff) > + > +static bool pud_aligned; > +static bool pmd_aligned; > + > +static void pte_basic_tests(struct page *page, pgprot_t prot) > +{ > + pte_t pte = mk_pte(page, prot); > + > + WARN_ON(!pte_same(pte, pte)); > + WARN_ON(!pte_young(pte_mkyoung(pte))); > + WARN_ON(!pte_dirty(pte_mkdirty(pte))); > + WARN_ON(!pte_write(pte_mkwrite(pte))); > + WARN_ON(pte_young(pte_mkold(pte))); > + WARN_ON(pte_dirty(pte_mkclean(pte))); > + WARN_ON(pte_write(pte_wrprotect(pte))); > +} > + > +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE > +static void pmd_basic_tests(struct page *page, pgprot_t prot) > +{ > + pmd_t pmd; > + > + /* > + * Memory block here must be PMD_SIZE aligned. Abort this > + * test in case we could not allocate such a memory block. > + */ > + if (!pmd_aligned) { > + pr_warn("Could not proceed with PMD tests\n"); > + return; > + } > + > + pmd = mk_pmd(page, prot); > + WARN_ON(!pmd_same(pmd, pmd)); > + WARN_ON(!pmd_young(pmd_mkyoung(pmd))); > + WARN_ON(!pmd_dirty(pmd_mkdirty(pmd))); > + WARN_ON(!pmd_write(pmd_mkwrite(pmd))); > + WARN_ON(pmd_young(pmd_mkold(pmd))); > + WARN_ON(pmd_dirty(pmd_mkclean(pmd))); > + WARN_ON(pmd_write(pmd_wrprotect(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))); > +} > +#else > +static void pmd_basic_tests(struct page *page, pgprot_t prot) { } > +#endif > + > +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD > +static void pud_basic_tests(struct page *page, pgprot_t prot) > +{ > + pud_t pud; > + > + /* > + * Memory block here must be PUD_SIZE aligned. Abort this > + * test in case we could not allocate such a memory block. > + */ > + if (!pud_aligned) { > + pr_warn("Could not proceed with PUD tests\n"); > + return; > + } > + > + pud = pfn_pud(page_to_pfn(page), prot); > + WARN_ON(!pud_same(pud, pud)); > + WARN_ON(!pud_young(pud_mkyoung(pud))); > + WARN_ON(!pud_write(pud_mkwrite(pud))); > + WARN_ON(pud_write(pud_wrprotect(pud))); > + WARN_ON(pud_young(pud_mkold(pud))); > + > +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK) > + /* > + * 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))); > +#endif > +} > +#else > +static void pud_basic_tests(struct page *page, pgprot_t prot) { } > +#endif > + > +static void p4d_basic_tests(struct page *page, pgprot_t prot) > +{ > + p4d_t p4d; > + > + memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t)); > + WARN_ON(!p4d_same(p4d, p4d)); > +} > + > +static void pgd_basic_tests(struct page *page, pgprot_t prot) > +{ > + pgd_t pgd; > + > + memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t)); > + WARN_ON(!pgd_same(pgd, pgd)); > +} > + > +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK) #ifdefs have to be avoided as much as possible, see below > +static void pud_clear_tests(pud_t *pudp) > +{ > + pud_t pud = READ_ONCE(*pudp); if (mm_pmd_folded() || __is_defined(__ARCH_HAS_4LEVEL_HACK)) 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 pud_populate_tests(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp) > +{ > + pud_t pud; > + if (mm_pmd_folded() || __is_defined(__ARCH_HAS_4LEVEL_HACK)) 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 Then the else branch goes away. > +static void pud_clear_tests(pud_t *pudp) { } > +static void pud_populate_tests(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp) > +{ > +} > +#endif > + > +#if !defined(__PAGETABLE_PUD_FOLDED) && !defined(__ARCH_HAS_5LEVEL_HACK) The same can be done here. > +static void p4d_clear_tests(p4d_t *p4dp) > +{ > + p4d_t p4d = READ_ONCE(*p4dp); > + > + 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 p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp) > +{ > + p4d_t p4d; > + > + /* > + * 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)); > +} > +#else > +static void p4d_clear_tests(p4d_t *p4dp) { } > +static void p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp) > +{ > +} > +#endif > + > +#ifndef __ARCH_HAS_5LEVEL_HACK And the same here (you already did part of it with testing mm_p4d_folded(mm) > +static void 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 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 > +static void pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { } > +static void pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, p4d_t *p4dp) > +{ > +} > +#endif > + > +static void pte_clear_tests(struct mm_struct *mm, pte_t *ptep) > +{ > + pte_t pte = READ_ONCE(*ptep); > + > + pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > + WRITE_ONCE(*ptep, pte); > + pte_clear(mm, 0, ptep); > + pte = READ_ONCE(*ptep); > + WARN_ON(!pte_none(pte)); > +} > + > +static void pmd_clear_tests(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 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 struct page *alloc_mapped_page(void) > +{ > + struct page *page; > + gfp_t gfp_mask = GFP_KERNEL | __GFP_ZERO; > + > + page = alloc_gigantic_page_order(get_order(PUD_SIZE), gfp_mask, > + first_memory_node, &node_states[N_MEMORY]); > + if (page) { > + pud_aligned = true; > + pmd_aligned = true; > + return page; > + } > + > + page = alloc_pages(gfp_mask, get_order(PMD_SIZE)); > + if (page) { > + pmd_aligned = true; > + return page; > + } > + return alloc_page(gfp_mask); > +} > + > +static void free_mapped_page(struct page *page) > +{ > + if (pud_aligned) { > + unsigned long pfn = page_to_pfn(page); > + > + free_contig_range(pfn, 1ULL << get_order(PUD_SIZE)); > + return; > + } > + > + if (pmd_aligned) { > + int order = get_order(PMD_SIZE); > + > + free_pages((unsigned long)page_address(page), order); > + return; > + } > + free_page((unsigned long)page_address(page)); > +} > + > +static unsigned long 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; > + > + WARN_ON(random_vaddr > TASK_SIZE); > + WARN_ON(random_vaddr < FIRST_USER_ADDRESS); > + return random_vaddr; > +} > + > +static int __init arch_pgtable_tests_init(void) > +{ > + struct mm_struct *mm; > + struct page *page; > + 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; > + unsigned long vaddr; > + > + prot = vm_get_page_prot(VMFLAGS); > + vaddr = get_random_vaddr(); > + mm = mm_alloc(); > + if (!mm) { > + pr_err("mm_struct allocation failed\n"); > + return 1; > + } > + > + page = alloc_mapped_page(); > + if (!page) { > + pr_err("memory allocation failed\n"); > + return 1; > + } > + > + 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(mm, pmdp, vaddr); > + > + /* > + * 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(page, prot); > + pmd_basic_tests(page, prot); > + pud_basic_tests(page, prot); > + p4d_basic_tests(page, prot); > + pgd_basic_tests(page, prot); > + > + pte_clear_tests(mm, ptep); > + pmd_clear_tests(pmdp); > + pud_clear_tests(pudp); > + p4d_clear_tests(p4dp); > + pgd_clear_tests(mm, pgdp); > + > + 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); > + > + free_mapped_page(page); > + return 0; Is there any benefit in keeping the module loaded once the tests are done ? Shouldn't the load fail instead ? > +} > + > +static void __exit arch_pgtable_tests_exit(void) { } Is this function really needed ? > + > +module_init(arch_pgtable_tests_init); > +module_exit(arch_pgtable_tests_exit); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_AUTHOR("Anshuman Khandual "); > +MODULE_DESCRIPTION("Test architecture page table helpers"); > Christophe