From patchwork Wed Jan 24 17:56:28 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 10182919 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0841860233 for ; Wed, 24 Jan 2018 17:58:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DFD64288B3 for ; Wed, 24 Jan 2018 17:58:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D04DB2891D; Wed, 24 Jan 2018 17:58:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id B8B45288B3 for ; Wed, 24 Jan 2018 17:58:22 +0000 (UTC) Received: (qmail 30603 invoked by uid 550); 24 Jan 2018 17:58:21 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 30585 invoked from network); 24 Jan 2018 17:58:20 -0000 From: Igor Stoppa To: , , , , , CC: , , , , , Igor Stoppa Date: Wed, 24 Jan 2018 19:56:28 +0200 Message-ID: <20180124175631.22925-4-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20180124175631.22925-1-igor.stoppa@huawei.com> References: <20180124175631.22925-1-igor.stoppa@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected Subject: [kernel-hardening] [PATCH 3/6] struct page: add field for vm_struct X-Virus-Scanned: ClamAV using ClamSMTP When a page is used for virtual memory, it is often necessary to obtian a handler to the corresponding vm_struct, which refers to the virtually continuous area generated when invoking vmalloc. The struct page has a "mapping" field, which can be re-used, to store a pointer to the parent area. This will avoid more expensive searches. As example, the function find_vm_area is reimplemented, to take advantage of the newly introduced field. Signed-off-by: Igor Stoppa --- include/linux/mm_types.h | 1 + mm/vmalloc.c | 18 +++++++++++++----- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index fd1af6b..c3a4825 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -84,6 +84,7 @@ struct page { void *s_mem; /* slab first object */ atomic_t compound_mapcount; /* first tail page */ /* page_deferred_list().next -- second tail page */ + struct vm_struct *area; }; /* Second double word */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6739420..44c5dfc 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1466,13 +1466,16 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags, */ struct vm_struct *find_vm_area(const void *addr) { - struct vmap_area *va; + struct page *page; - va = find_vmap_area((unsigned long)addr); - if (va && va->flags & VM_VM_AREA) - return va->vm; + if (unlikely(!is_vmalloc_addr(addr))) + return NULL; - return NULL; + page = vmalloc_to_page(addr); + if (unlikely(!page)) + return NULL; + + return page->area; } /** @@ -1536,6 +1539,7 @@ static void __vunmap(const void *addr, int deallocate_pages) struct page *page = area->pages[i]; BUG_ON(!page); + page->area = NULL; __free_pages(page, 0); } @@ -1744,6 +1748,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, const void *caller) { struct vm_struct *area; + unsigned int page_counter; void *addr; unsigned long real_size = size; @@ -1769,6 +1774,9 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, kmemleak_vmalloc(area, size, gfp_mask); + for (page_counter = 0; page_counter < area->nr_pages; page_counter++) + area->pages[page_counter]->area = area; + return addr; fail: