From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75657C636CA for ; Tue, 20 Jul 2021 22:16:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5531861242 for ; Tue, 20 Jul 2021 22:16:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233213AbhGTVeM (ORCPT ); Tue, 20 Jul 2021 17:34:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:51566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230039AbhGTVdd (ORCPT ); Tue, 20 Jul 2021 17:33:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 57C056101B; Tue, 20 Jul 2021 22:14:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1626819243; bh=tZAfvRi0aUct4l8nX3WNozFiIlLNmoL78fbdSvKCoGw=; h=Date:From:To:Subject:From; b=L+yRLwaBz+QF6HGr0/RZfAXCEc0jvc028s5Gsu2gCRPUw1zMtStTZUD35u45i469J nCxUcjN/PBrzMakV8G+NTI4wANizmVJrjVOhfh9l8517fGYkSev30Z2Xh5PT5HVbSv 04yFx4t7r94oVESZvcdYpiGle7I5JfPJeZqd/9K8= Date: Tue, 20 Jul 2021 15:14:02 -0700 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, anshuman.khandual@arm.com, gshan@redhat.com Subject: + mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch added to -mm tree Message-ID: <20210720221402.rgNLV%akpm@linux-foundation.org> User-Agent: s-nail v14.9.10 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/debug_vm_pgtable: introduce struct pgtable_debug_args has been added to the -mm tree. Its filename is mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Gavin Shan Subject: mm/debug_vm_pgtable: introduce struct pgtable_debug_args Patch series "mm/debug_vm_pgtable: Enhancements", v3. There are a couple of issues with current implementations and this series tries to resolve the issues: (a) All needed information are scattered in variables, passed to various test functions. The code is organized in pretty much relaxed fashion. (b) The page isn't allocated from buddy during page table entry modifying tests. The page can be invalid, conflicting to the implementations of set_xxx_at() on ARM64. The target page is accessed so that the iCache can be flushed when execution permission is given on ARM64. Besides, the target page can be unmapped and access to it causes kernel crash. "struct pgtable_debug_args" is introduced to address issue (a). For issue (b), the used page is allocated from buddy in page table entry modifying tests. The corresponding tets will be skipped if we fail to allocate the (huge) page. For other test cases, the original page around to kernel symbol (@start_kernel) is still used. The patches are organized as below. PATCH[2-10] could be combined to one patch, but it will make the review harder: PATCH[1] introduces "struct pgtable_debug_args" as place holder of all needed information. With it, the old and new implementation can coexist. PATCH[2-10] uses "struct pgtable_debug_args" in various test functions. PATCH[11] removes the unused code for old implementation. PATCH[12] fixes the issue of corrupted page flag for ARM64 This patch (of 12): In debug_vm_pgtable(), there are many local variables introduced to track the needed information and they are passed to the functions for various test cases. It'd better to introduce a struct as place holder for these information. With it, what the functions for various test cases need is the struct, to simplify the code. It also makes code easier to be maintained. Besides, set_xxx_at() could access the data on the corresponding pages in the page table modifying tests. So the accessed pages in the tests should have been allocated from buddy. Otherwise, we're accessing pages that aren't owned by us. This causes issues like page flag corruption. This introduces "struct pgtable_debug_args". The struct is initialized and destroyed, but the information in the struct isn't used yet. They will be used in subsequent patches. Link: https://lkml.kernel.org/r/20210719130613.334901-1-gshan@redhat.com Link: https://lkml.kernel.org/r/20210719130613.334901-2-gshan@redhat.com Signed-off-by: Gavin Shan Cc: Anshuman Khandual Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/debug_vm_pgtable.c | 197 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 196 insertions(+), 1 deletion(-) --- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args +++ a/mm/debug_vm_pgtable.c @@ -58,6 +58,36 @@ #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK) #define RANDOM_NZVALUE GENMASK(7, 0) +struct pgtable_debug_args { + struct mm_struct *mm; + struct vm_area_struct *vma; + + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep; + + p4d_t *start_p4dp; + pud_t *start_pudp; + pmd_t *start_pmdp; + pgtable_t start_ptep; + + unsigned long vaddr; + pgprot_t page_prot; + pgprot_t page_prot_none; + + unsigned long pud_pfn; + unsigned long pmd_pfn; + unsigned long pte_pfn; + + unsigned long fixed_pgd_pfn; + unsigned long fixed_p4d_pfn; + unsigned long fixed_pud_pfn; + unsigned long fixed_pmd_pfn; + unsigned long fixed_pte_pfn; +}; + static void __init pte_basic_tests(unsigned long pfn, int idx) { pgprot_t prot = protection_map[idx]; @@ -955,8 +985,167 @@ static unsigned long __init get_random_v return random_vaddr; } +static void __init destroy_args(struct pgtable_debug_args *args) +{ + struct page *page = NULL; + + /* Free (huge) page */ + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && + has_transparent_hugepage() && + args->pud_pfn != ULONG_MAX) { + page = pfn_to_page(args->pud_pfn); + __free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT); + } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + has_transparent_hugepage() && + args->pmd_pfn != ULONG_MAX) { + page = pfn_to_page(args->pmd_pfn); + __free_pages(page, HPAGE_PMD_ORDER); + } else if (args->pte_pfn != ULONG_MAX) { + page = pfn_to_page(args->pte_pfn); + __free_pages(page, 0); + } + + /* Free page table */ + if (args->start_ptep) { + pte_free(args->mm, args->start_ptep); + mm_dec_nr_ptes(args->mm); + } + + if (args->start_pmdp) { + pmd_free(args->mm, args->start_pmdp); + mm_dec_nr_pmds(args->mm); + } + + if (args->start_pudp) { + pud_free(args->mm, args->start_pudp); + mm_dec_nr_puds(args->mm); + } + + if (args->start_p4dp) + p4d_free(args->mm, args->p4dp); + + /* Free vma and mm struct */ + if (args->vma) + vm_area_free(args->vma); + if (args->mm) + mmdrop(args->mm); +} + +static int __init init_args(struct pgtable_debug_args *args) +{ + struct page *page = NULL; + phys_addr_t phys; + int ret = 0; + + /* Initialize the debugging data */ + memset(args, 0, sizeof(*args)); + args->page_prot = vm_get_page_prot(VMFLAGS); + args->page_prot_none = __P000; + args->pud_pfn = ULONG_MAX; + args->pmd_pfn = ULONG_MAX; + args->pte_pfn = ULONG_MAX; + args->fixed_pgd_pfn = ULONG_MAX; + args->fixed_p4d_pfn = ULONG_MAX; + args->fixed_pud_pfn = ULONG_MAX; + args->fixed_pmd_pfn = ULONG_MAX; + args->fixed_pte_pfn = ULONG_MAX; + + /* Allocate mm and vma */ + args->mm = mm_alloc(); + if (!args->mm) { + pr_err("Failed to allocate mm struct\n"); + ret = -ENOMEM; + goto error; + } + + args->vma = vm_area_alloc(args->mm); + if (!args->vma) { + pr_err("Failed to allocate vma\n"); + ret = -ENOMEM; + goto error; + } + + /* Figure out the virtual address and allocate page table entries */ + args->vaddr = get_random_vaddr(); + args->pgdp = pgd_offset(args->mm, args->vaddr); + args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr); + args->pudp = args->p4dp ? + pud_alloc(args->mm, args->p4dp, args->vaddr) : NULL; + args->pmdp = args->pudp ? + pmd_alloc(args->mm, args->pudp, args->vaddr) : NULL; + args->ptep = args->pmdp ? + pte_alloc_map(args->mm, args->pmdp, args->vaddr) : NULL; + if (!args->ptep) { + pr_err("Failed to allocate page table\n"); + ret = -ENOMEM; + goto error; + } + + /* + * The above page table entries will be modified. Lets save the + * page table entries so that they can be released when the tests + * are completed. + */ + args->start_p4dp = p4d_offset(args->pgdp, 0UL); + args->start_pudp = pud_offset(args->p4dp, 0UL); + args->start_pmdp = pmd_offset(args->pudp, 0UL); + args->start_ptep = pmd_pgtable(READ_ONCE(*(args->pmdp))); + + /* + * Figure out the fixed addresses, which are all around the kernel + * symbol (@start_kernel). The corresponding PFNs might be invalid, + * but it's fine as the following tests won't access the pages. + */ + phys = __pa_symbol(&start_kernel); + args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK); + args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK); + args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK); + args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK); + args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK); + + /* + * Allocate (huge) pages because some of the tests need to access + * the data in the pages. The corresponding tests will be skipped + * if we fail to allocate (huge) pages. + */ + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && + has_transparent_hugepage()) { + page = alloc_pages(GFP_KERNEL | __GFP_NOWARN, + HPAGE_PUD_SHIFT - PAGE_SHIFT); + if (page) { + args->pud_pfn = page_to_pfn(page); + args->pmd_pfn = args->pud_pfn; + args->pte_pfn = args->pud_pfn; + return 0; + } + } + + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + has_transparent_hugepage()) { + page = alloc_pages(GFP_KERNEL | __GFP_NOWARN, HPAGE_PMD_ORDER); + if (page) { + args->pmd_pfn = page_to_pfn(page); + args->pte_pfn = args->pmd_pfn; + return 0; + } + } + + page = alloc_pages(GFP_KERNEL, 0); + if (page) + args->pte_pfn = page_to_pfn(page); + + return 0; + +error: + destroy_args(args); + return ret; +} + static int __init debug_vm_pgtable(void) { + struct pgtable_debug_args args; struct vm_area_struct *vma; struct mm_struct *mm; pgd_t *pgdp; @@ -970,9 +1159,13 @@ static int __init debug_vm_pgtable(void) unsigned long vaddr, pte_aligned, pmd_aligned; unsigned long pud_aligned, p4d_aligned, pgd_aligned; spinlock_t *ptl = NULL; - int idx; + int idx, ret; pr_info("Validating architecture page table helpers\n"); + ret = init_args(&args); + if (ret) + return ret; + prot = vm_get_page_prot(VMFLAGS); vaddr = get_random_vaddr(); mm = mm_alloc(); @@ -1127,6 +1320,8 @@ static int __init debug_vm_pgtable(void) mm_dec_nr_pmds(mm); mm_dec_nr_ptes(mm); mmdrop(mm); + + destroy_args(&args); return 0; } late_initcall(debug_vm_pgtable); _ Patches currently in -mm which might be from gshan@redhat.com are mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-basic-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-leaf-and-savewrite-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-protnone-and-devmap-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-soft_dirty-and-swap-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-migration-and-thp-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pte-modifying-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pmd-modifying-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pud-modifying-tests.patch mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pgd-and-p4d-modifying-tests.patch mm-debug_vm_pgtable-remove-unused-code.patch mm-debug_vm_pgtable-fix-corrupted-page-flag.patch