Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932931AbcLHQ2q (ORCPT ); Thu, 8 Dec 2016 11:28:46 -0500 Received: from mga14.intel.com ([192.55.52.115]:54725 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932562AbcLHQWe (ORCPT ); Thu, 8 Dec 2016 11:22:34 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,320,1477983600"; d="scan'208";a="1069672990" From: "Kirill A. Shutemov" To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" Cc: Andi Kleen , Dave Hansen , Andy Lutomirski , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [RFC, PATCHv1 14/28] mm: introduce __p4d_alloc() Date: Thu, 8 Dec 2016 19:21:36 +0300 Message-Id: <20161208162150.148763-16-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161208162150.148763-1-kirill.shutemov@linux.intel.com> References: <20161208162150.148763-1-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1114 Lines: 43 For full 5-level paging we need a helper to allocate p4d pagetable. Signed-off-by: Kirill A. Shutemov --- mm/memory.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index fd1a3319f413..ce7639fdeeda 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3789,6 +3789,29 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address, } EXPORT_SYMBOL_GPL(handle_mm_fault); +#ifndef __PAGETABLE_P4D_FOLDED +/* + * Allocate p4d page table. + * We've already handled the fast-path in-line. + */ +int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) +{ + p4d_t *new = p4d_alloc_one(mm, address); + if (!new) + return -ENOMEM; + + smp_wmb(); /* See comment in __pte_alloc */ + + spin_lock(&mm->page_table_lock); + if (pgd_present(*pgd)) /* Another has populated it */ + p4d_free(mm, new); + else + pgd_populate(mm, pgd, new); + spin_unlock(&mm->page_table_lock); + return 0; +} +#endif /* __PAGETABLE_P4D_FOLDED */ + #ifndef __PAGETABLE_PUD_FOLDED /* * Allocate page upper directory. -- 2.10.2