From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 993856B0038 for ; Thu, 16 Mar 2017 11:27:13 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id e5so97036526pgk.1 for ; Thu, 16 Mar 2017 08:27:13 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTPS id t6si5641811pgo.14.2017.03.16.08.27.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Mar 2017 08:27:12 -0700 (PDT) From: "Kirill A. Shutemov" Subject: [PATCH 2/7] mm/gup: Move permission checks into helpers Date: Thu, 16 Mar 2017 18:26:50 +0300 Message-Id: <20170316152655.37789-3-kirill.shutemov@linux.intel.com> In-Reply-To: <20170316152655.37789-1-kirill.shutemov@linux.intel.com> References: <20170316152655.37789-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Dave Hansen , "Aneesh Kumar K . V" , Steve Capper , Dann Frazier , Catalin Marinas , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" This is preparation patch for transition of x86 to generic GUP_fast() implementation. On x86, we would need to do additional permission checks to determinate if access is allowed. Let's abstract it out into separate helpers. Signed-off-by: Kirill A. Shutemov --- include/asm-generic/pgtable.h | 25 +++++++++++++++++++++++++ mm/gup.c | 15 ++++++++++----- 2 files changed, 35 insertions(+), 5 deletions(-) diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 1fad160f35de..7dfa767dc680 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -341,6 +341,31 @@ static inline int pte_unused(pte_t pte) } #endif +#ifndef pte_access_permitted +#define pte_access_permitted(pte, write) \ + (pte_present(pte) && (!(write) || pte_write(pte))) +#endif + +#ifndef pmd_access_permitted +#define pmd_access_permitted(pmd, write) \ + (pmd_present(pmd) && (!(write) || pmd_write(pmd))) +#endif + +#ifndef pud_access_permitted +#define pud_access_permitted(pud, write) \ + (pud_present(pud) && (!(write) || pud_write(pud))) +#endif + +#ifndef p4d_access_permitted +#define p4d_access_permitted(p4d, write) \ + (p4d_present(p4d) && (!(write) || p4d_write(p4d))) +#endif + +#ifndef pgd_access_permitted +#define pgd_access_permitted(pgd, write) \ + (pgd_present(pgd) && (!(write) || pgd_write(pgd))) +#endif + #ifndef __HAVE_ARCH_PMD_SAME #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) diff --git a/mm/gup.c b/mm/gup.c index 3f2338ba3402..a62a778ce4ec 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1212,8 +1212,13 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, * Similar to the PMD case below, NUMA hinting must take slow * path using the pte_protnone check. */ - if (!pte_present(pte) || pte_special(pte) || - pte_protnone(pte) || (write && !pte_write(pte))) + if (pte_protnone(pte)) + goto pte_unmap; + + if (!pte_access_permitted(pte, write)) + goto pte_unmap; + + if (pte_special(pte)) goto pte_unmap; VM_BUG_ON(!pfn_valid(pte_pfn(pte))); @@ -1264,7 +1269,7 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, struct page *head, *page; int refs; - if (write && !pmd_write(orig)) + if (!pmd_access_permitted(orig, write)) return 0; refs = 0; @@ -1299,7 +1304,7 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, struct page *head, *page; int refs; - if (write && !pud_write(orig)) + if (!pud_access_permitted(orig, write)) return 0; refs = 0; @@ -1335,7 +1340,7 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr, int refs; struct page *head, *page; - if (write && !pgd_write(orig)) + if (!pgd_access_permitted(orig, write)) return 0; refs = 0; -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org