Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752616AbdHIUMc (ORCPT ); Wed, 9 Aug 2017 16:12:32 -0400 Received: from mail-it0-f43.google.com ([209.85.214.43]:37238 "EHLO mail-it0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751891AbdHIUI4 (ORCPT ); Wed, 9 Aug 2017 16:08:56 -0400 From: Tycho Andersen To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , Tycho Andersen Subject: [PATCH v5 01/10] mm: add MAP_HUGETLB support to vm_mmap Date: Wed, 9 Aug 2017 14:07:46 -0600 Message-Id: <20170809200755.11234-2-tycho@docker.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170809200755.11234-1-tycho@docker.com> References: <20170809200755.11234-1-tycho@docker.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3371 Lines: 107 vm_mmap is exported, which means kernel modules can use it. In particular, for testing XPFO support, we want to use it with the MAP_HUGETLB flag, so let's support it via vm_mmap. Signed-off-by: Tycho Andersen Tested-by: Marco Benatto --- include/linux/mm.h | 2 ++ mm/mmap.c | 19 +------------------ mm/util.c | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 35 insertions(+), 18 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 46b9ac5e8569..e3bce22fe0f7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2140,6 +2140,8 @@ struct vm_unmapped_area_info { extern unsigned long unmapped_area(struct vm_unmapped_area_info *info); extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info); +struct file *map_hugetlb_setup(unsigned long *len, unsigned long flags); + /* * Search for an unmapped address range. * diff --git a/mm/mmap.c b/mm/mmap.c index f19efcf75418..f24fc14808e1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1490,24 +1490,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) goto out_fput; } else if (flags & MAP_HUGETLB) { - struct user_struct *user = NULL; - struct hstate *hs; - - hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); - if (!hs) - return -EINVAL; - - len = ALIGN(len, huge_page_size(hs)); - /* - * VM_NORESERVE is used because the reservations will be - * taken when vm_ops->mmap() is called - * A dummy user value is used because we are not locking - * memory so no accounting is necessary - */ - file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, - VM_NORESERVE, - &user, HUGETLB_ANONHUGE_INODE, - (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); + file = map_hugetlb_setup(&len, flags); if (IS_ERR(file)) return PTR_ERR(file); } diff --git a/mm/util.c b/mm/util.c index 7b07ec852e01..aac2c58d6f52 100644 --- a/mm/util.c +++ b/mm/util.c @@ -340,6 +340,29 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, return ret; } +struct file *map_hugetlb_setup(unsigned long *len, unsigned long flags) +{ + struct user_struct *user = NULL; + struct hstate *hs; + + hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); + if (!hs) + return ERR_PTR(-EINVAL); + + *len = ALIGN(*len, huge_page_size(hs)); + + /* + * VM_NORESERVE is used because the reservations will be + * taken when vm_ops->mmap() is called + * A dummy user value is used because we are not locking + * memory so no accounting is necessary + */ + return hugetlb_file_setup(HUGETLB_ANON_FILE, *len, + VM_NORESERVE, + &user, HUGETLB_ANONHUGE_INODE, + (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); +} + unsigned long vm_mmap(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long offset) @@ -349,6 +372,15 @@ unsigned long vm_mmap(struct file *file, unsigned long addr, if (unlikely(offset_in_page(offset))) return -EINVAL; + if (flag & MAP_HUGETLB) { + if (file) + return -EINVAL; + + file = map_hugetlb_setup(&len, flag); + if (IS_ERR(file)) + return PTR_ERR(file); + } + return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); } EXPORT_SYMBOL(vm_mmap); -- 2.11.0