From patchwork Mon Jul 13 03:23:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 11658631 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 69F816C1 for ; Mon, 13 Jul 2020 03:24:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2ED042075F for ; Mon, 13 Jul 2020 03:24:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2ED042075F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4C9E58D0007; Sun, 12 Jul 2020 23:24:16 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 453288D0002; Sun, 12 Jul 2020 23:24:16 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F3428D0007; Sun, 12 Jul 2020 23:24:16 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0150.hostedemail.com [216.40.44.150]) by kanga.kvack.org (Postfix) with ESMTP id 16AB78D0002 for ; Sun, 12 Jul 2020 23:24:16 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id CF033180AD820 for ; Mon, 13 Jul 2020 03:24:15 +0000 (UTC) X-FDA: 77031609270.03.rub26_19155d426ee5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id 9AD4728A4E9 for ; Mon, 13 Jul 2020 03:24:15 +0000 (UTC) X-Spam-Summary: 1,0,0,53962a5a944e4702,d41d8cd98f00b204,anshuman.khandual@arm.com,,RULES_HIT:4:41:334:355:368:369:379:541:800:960:966:973:988:989:1260:1261:1345:1359:1431:1437:1605:1730:1747:1777:1792:1963:2196:2199:2393:2559:2562:2640:2693:3138:3139:3140:3141:3142:3167:3865:3868:3871:3874:4250:4321:4385:4605:5007:6117:6119:6261:6742:6743:7903:8634:10004:11026:11233:11473:11658:11914:12043:12291:12296:12297:12438:12555:12683:12895:13255:13548:13846:14096:14394:21080:21433:21451:21627:21939:21990:30054:30089,0,RBL:217.140.110.172:@arm.com:.lbl8.mailshell.net-62.2.0.100 64.100.201.201;04yrqxyrdpdfjb99ff15h5ss8rci9ochnfz1h6wnfiykdyzu8s9339hi4crrxex.chxprtegrosgepxnzfjp5ujkwj6kiwm968oodyy4sq4hh3sibqis1wkdkkoe4dc.4-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: rub26_19155d426ee5 X-Filterd-Recvd-Size: 16418 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 13 Jul 2020 03:24:14 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 362B81FB; Sun, 12 Jul 2020 20:24:14 -0700 (PDT) Received: from p8cg001049571a15.arm.com (unknown [10.163.87.124]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5B5423F7D8; Sun, 12 Jul 2020 20:24:02 -0700 (PDT) From: Anshuman Khandual To: linux-mm@kvack.org Cc: agordeev@linux.ibm.com, ziy@nvidia.com, gerald.schaefer@de.ibm.com, christophe.leroy@c-s.fr, christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com, rppt@kernel.org, cai@lca.pw, Anshuman Khandual , Andrew Morton , Mike Rapoport , Vineet Gupta , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "Kirill A . Shutemov" , Paul Walmsley , Palmer Dabbelt , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-riscv@lists.infradead.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V5 2/4] mm/debug_vm_pgtable: Add tests validating advanced arch page table helpers Date: Mon, 13 Jul 2020 08:53:05 +0530 Message-Id: <1594610587-4172-3-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1594610587-4172-1-git-send-email-anshuman.khandual@arm.com> References: <1594610587-4172-1-git-send-email-anshuman.khandual@arm.com> X-Rspamd-Queue-Id: 9AD4728A4E9 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This adds new tests validating for these following arch advanced page table helpers. These tests create and test specific mapping types at various page table levels. 1. pxxp_set_wrprotect() 2. pxxp_get_and_clear() 3. pxxp_set_access_flags() 4. pxxp_get_and_clear_full() 5. pxxp_test_and_clear_young() 6. pxx_leaf() 7. pxx_set_huge() 8. pxx_(clear|mk)_savedwrite() 9. huge_pxxp_xxx() Cc: Andrew Morton Cc: Gerald Schaefer Cc: Christophe Leroy Cc: Mike Rapoport Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Kirill A. Shutemov Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: linux-riscv@lists.infradead.org Cc: x86@kernel.org Cc: linux-mm@kvack.org Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Tested-by: Vineet Gupta #arc Suggested-by: Catalin Marinas Signed-off-by: Anshuman Khandual --- mm/debug_vm_pgtable.c | 312 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 312 insertions(+) diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 2fac47db3eb7..9c7c11eecf17 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -28,6 +29,7 @@ #include #include #include +#include #define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC) @@ -55,6 +57,55 @@ static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte)))); } +static void __init pte_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pte_t *ptep, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ + pte_t pte = pfn_pte(pfn, prot); + + pte = pfn_pte(pfn, prot); + set_pte_at(mm, vaddr, ptep, pte); + ptep_set_wrprotect(mm, vaddr, ptep); + pte = ptep_get(ptep); + WARN_ON(pte_write(pte)); + + pte = pfn_pte(pfn, prot); + set_pte_at(mm, vaddr, ptep, pte); + ptep_get_and_clear(mm, vaddr, ptep); + pte = ptep_get(ptep); + WARN_ON(!pte_none(pte)); + + pte = pfn_pte(pfn, prot); + pte = pte_wrprotect(pte); + pte = pte_mkclean(pte); + set_pte_at(mm, vaddr, ptep, pte); + pte = pte_mkwrite(pte); + pte = pte_mkdirty(pte); + ptep_set_access_flags(vma, vaddr, ptep, pte, 1); + pte = ptep_get(ptep); + WARN_ON(!(pte_write(pte) && pte_dirty(pte))); + + pte = pfn_pte(pfn, prot); + set_pte_at(mm, vaddr, ptep, pte); + ptep_get_and_clear_full(mm, vaddr, ptep, 1); + pte = ptep_get(ptep); + WARN_ON(!pte_none(pte)); + + pte = pte_mkyoung(pte); + set_pte_at(mm, vaddr, ptep, pte); + ptep_test_and_clear_young(vma, vaddr, ptep); + pte = ptep_get(ptep); + WARN_ON(pte_young(pte)); +} + +static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot) +{ + pte_t pte = pfn_pte(pfn, prot); + + WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte)))); + WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte)))); +} #ifdef CONFIG_TRANSPARENT_HUGEPAGE static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { @@ -77,6 +128,90 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) WARN_ON(!pmd_bad(pmd_mkhuge(pmd))); } +static void __init pmd_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pmd_t *pmdp, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ + pmd_t pmd = pfn_pmd(pfn, prot); + + if (!has_transparent_hugepage()) + return; + + /* Align the address wrt HPAGE_PMD_SIZE */ + vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE; + + pmd = pfn_pmd(pfn, prot); + set_pmd_at(mm, vaddr, pmdp, pmd); + pmdp_set_wrprotect(mm, vaddr, pmdp); + pmd = READ_ONCE(*pmdp); + WARN_ON(pmd_write(pmd)); + + pmd = pfn_pmd(pfn, prot); + set_pmd_at(mm, vaddr, pmdp, pmd); + pmdp_huge_get_and_clear(mm, vaddr, pmdp); + pmd = READ_ONCE(*pmdp); + WARN_ON(!pmd_none(pmd)); + + pmd = pfn_pmd(pfn, prot); + pmd = pmd_wrprotect(pmd); + pmd = pmd_mkclean(pmd); + set_pmd_at(mm, vaddr, pmdp, pmd); + pmd = pmd_mkwrite(pmd); + pmd = pmd_mkdirty(pmd); + pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1); + pmd = READ_ONCE(*pmdp); + WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd))); + + pmd = pmd_mkhuge(pfn_pmd(pfn, prot)); + set_pmd_at(mm, vaddr, pmdp, pmd); + pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1); + pmd = READ_ONCE(*pmdp); + WARN_ON(!pmd_none(pmd)); + + pmd = pmd_mkyoung(pmd); + set_pmd_at(mm, vaddr, pmdp, pmd); + pmdp_test_and_clear_young(vma, vaddr, pmdp); + pmd = READ_ONCE(*pmdp); + WARN_ON(pmd_young(pmd)); +} + +static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) +{ + pmd_t pmd = pfn_pmd(pfn, prot); + + /* + * PMD based THP is a leaf entry. + */ + pmd = pmd_mkhuge(pmd); + WARN_ON(!pmd_leaf(pmd)); +} + +static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) +{ + pmd_t pmd; + + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + return; + /* + * X86 defined pmd_set_huge() verifies that the given + * PMD is not a populated non-leaf entry. + */ + WRITE_ONCE(*pmdp, __pmd(0)); + WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot)); + WARN_ON(!pmd_clear_huge(pmdp)); + pmd = READ_ONCE(*pmdp); + WARN_ON(!pmd_none(pmd)); +} + +static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) +{ + pmd_t pmd = pfn_pmd(pfn, prot); + + WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd)))); + WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd)))); +} + #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { @@ -100,12 +235,119 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) */ WARN_ON(!pud_bad(pud_mkhuge(pud))); } + +static void __init pud_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pud_t *pudp, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ + pud_t pud = pfn_pud(pfn, prot); + + if (!has_transparent_hugepage()) + return; + + /* Align the address wrt HPAGE_PUD_SIZE */ + vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE; + + set_pud_at(mm, vaddr, pudp, pud); + pudp_set_wrprotect(mm, vaddr, pudp); + pud = READ_ONCE(*pudp); + WARN_ON(pud_write(pud)); + +#ifndef __PAGETABLE_PMD_FOLDED + pud = pfn_pud(pfn, prot); + set_pud_at(mm, vaddr, pudp, pud); + pudp_huge_get_and_clear(mm, vaddr, pudp); + pud = READ_ONCE(*pudp); + WARN_ON(!pud_none(pud)); + + pud = pfn_pud(pfn, prot); + set_pud_at(mm, vaddr, pudp, pud); + pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1); + pud = READ_ONCE(*pudp); + WARN_ON(!pud_none(pud)); +#endif /* __PAGETABLE_PMD_FOLDED */ + pud = pfn_pud(pfn, prot); + pud = pud_wrprotect(pud); + pud = pud_mkclean(pud); + set_pud_at(mm, vaddr, pudp, pud); + pud = pud_mkwrite(pud); + pud = pud_mkdirty(pud); + pudp_set_access_flags(vma, vaddr, pudp, pud, 1); + pud = READ_ONCE(*pudp); + WARN_ON(!(pud_write(pud) && pud_dirty(pud))); + + pud = pud_mkyoung(pud); + set_pud_at(mm, vaddr, pudp, pud); + pudp_test_and_clear_young(vma, vaddr, pudp); + pud = READ_ONCE(*pudp); + WARN_ON(pud_young(pud)); +} + +static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) +{ + pud_t pud = pfn_pud(pfn, prot); + + /* + * PUD based THP is a leaf entry. + */ + pud = pud_mkhuge(pud); + WARN_ON(!pud_leaf(pud)); +} + +static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) +{ + pud_t pud; + + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + return; + /* + * X86 defined pud_set_huge() verifies that the given + * PUD is not a populated non-leaf entry. + */ + WRITE_ONCE(*pudp, __pud(0)); + WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot)); + WARN_ON(!pud_clear_huge(pudp)); + pud = READ_ONCE(*pudp); + WARN_ON(!pud_none(pud)); +} #else /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } +static void __init pud_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pud_t *pudp, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ +} +static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { } +static void __init pud_huge_tests(pud_t *pudp, 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) { } +static void __init pmd_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pmd_t *pmdp, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ +} +static void __init pud_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, pud_t *pudp, + unsigned long pfn, unsigned long vaddr, + pgprot_t prot) +{ +} +static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) { } +static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { } +static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) +{ +} +static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) +{ +} +static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) { } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot) @@ -495,8 +737,56 @@ static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot) WARN_ON(!pte_huge(pte_mkhuge(pte))); #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ } + +static void __init hugetlb_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, + pte_t *ptep, unsigned long pfn, + unsigned long vaddr, pgprot_t prot) +{ + struct page *page = pfn_to_page(pfn); + pte_t pte = ptep_get(ptep); + unsigned long paddr = __pfn_to_phys(pfn) & PMD_MASK; + + pte = pte_mkhuge(mk_pte(pfn_to_page(PHYS_PFN(paddr)), prot)); + set_huge_pte_at(mm, vaddr, ptep, pte); + barrier(); + WARN_ON(!pte_same(pte, huge_ptep_get(ptep))); + huge_pte_clear(mm, vaddr, ptep, PMD_SIZE); + pte = huge_ptep_get(ptep); + WARN_ON(!huge_pte_none(pte)); + + pte = mk_huge_pte(page, prot); + set_huge_pte_at(mm, vaddr, ptep, pte); + barrier(); + huge_ptep_set_wrprotect(mm, vaddr, ptep); + pte = huge_ptep_get(ptep); + WARN_ON(huge_pte_write(pte)); + + pte = mk_huge_pte(page, prot); + set_huge_pte_at(mm, vaddr, ptep, pte); + barrier(); + huge_ptep_get_and_clear(mm, vaddr, ptep); + pte = huge_ptep_get(ptep); + WARN_ON(!huge_pte_none(pte)); + + pte = mk_huge_pte(page, prot); + pte = huge_pte_wrprotect(pte); + set_huge_pte_at(mm, vaddr, ptep, pte); + barrier(); + pte = huge_pte_mkwrite(pte); + pte = huge_pte_mkdirty(pte); + huge_ptep_set_access_flags(vma, vaddr, ptep, pte, 1); + pte = huge_ptep_get(ptep); + WARN_ON(!(huge_pte_write(pte) && huge_pte_dirty(pte))); +} #else /* !CONFIG_HUGETLB_PAGE */ static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot) { } +static void __init hugetlb_advanced_tests(struct mm_struct *mm, + struct vm_area_struct *vma, + pte_t *ptep, unsigned long pfn, + unsigned long vaddr, pgprot_t prot) +{ +} #endif /* CONFIG_HUGETLB_PAGE */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -568,6 +858,7 @@ static unsigned long __init get_random_vaddr(void) static int __init debug_vm_pgtable(void) { + struct vm_area_struct *vma; struct mm_struct *mm; pgd_t *pgdp; p4d_t *p4dp, *saved_p4dp; @@ -596,6 +887,12 @@ static int __init debug_vm_pgtable(void) */ protnone = __P000; + vma = vm_area_alloc(mm); + if (!vma) { + pr_err("vma 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 @@ -644,6 +941,20 @@ static int __init debug_vm_pgtable(void) p4d_clear_tests(mm, p4dp); pgd_clear_tests(mm, pgdp); + pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); + pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot); + pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot); + hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); + + pmd_leaf_tests(pmd_aligned, prot); + pud_leaf_tests(pud_aligned, prot); + + pmd_huge_tests(pmdp, pmd_aligned, prot); + pud_huge_tests(pudp, pud_aligned, prot); + + pte_savedwrite_tests(pte_aligned, prot); + pmd_savedwrite_tests(pmd_aligned, prot); + pte_unmap_unlock(ptep, ptl); pmd_populate_tests(mm, pmdp, saved_ptep); @@ -678,6 +989,7 @@ static int __init debug_vm_pgtable(void) pmd_free(mm, saved_pmdp); pte_free(mm, saved_ptep); + vm_area_free(vma); mm_dec_nr_puds(mm); mm_dec_nr_pmds(mm); mm_dec_nr_ptes(mm);