Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754835AbZGNOW2 (ORCPT ); Tue, 14 Jul 2009 10:22:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754812AbZGNOWW (ORCPT ); Tue, 14 Jul 2009 10:22:22 -0400 Received: from smtp.gentoo.org ([140.211.166.183]:33481 "EHLO smtp.gentoo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753601AbZGNOWV (ORCPT ); Tue, 14 Jul 2009 10:22:21 -0400 From: Mike Frysinger To: linux-kernel@vger.kernel.org Cc: uclinux-dist-devel@blackfin.uclinux.org, Bernd Schmidt , Bryan Wu , David Howells Subject: [PATCH] NOMMU: add support for Memory Protection Units (MPU) Date: Tue, 14 Jul 2009 10:22:20 -0400 Message-Id: <1247581340-20031-1-git-send-email-vapier@gentoo.org> X-Mailer: git-send-email 1.6.3.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3026 Lines: 108 From: Bernd Schmidt Some architectures (like the Blackfin arch) implement some of the "simpler" features that one would expect out of a MMU such as memory protection. In our case, we actually get read/write/exec protection down to the page boundary so processes can't stomp on each other let alone the kernel. There is a performance decrease (which depends greatly on the workload) however as the hardware/software interaction was not optimized at design time. Signed-off-by: Bernd Schmidt Signed-off-by: Bryan Wu Signed-off-by: Mike Frysinger CC: David Howells --- kernel/module.c | 5 +++++ mm/nommu.c | 25 +++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 0 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 0a04983..e1a3dfc 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include #include @@ -1519,6 +1520,10 @@ static void free_module(struct module *mod) /* Finally, free the core (containing the module structure) */ module_free(mod, mod->module_core); + +#ifdef CONFIG_MPU + update_protections(current->mm); +#endif } void *__symbol_get(const char *symbol) diff --git a/mm/nommu.c b/mm/nommu.c index 53cab10..a0269e5 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -33,6 +33,7 @@ #include #include #include +#include #include "internal.h" static inline __attribute__((format(printf, 1, 2))) @@ -640,11 +641,23 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) struct vm_area_struct *pvma, **pp; struct address_space *mapping; struct rb_node **p, *parent; +#ifdef CONFIG_MPU + long start; +#endif kenter(",%p", vma); BUG_ON(!vma->vm_region); +#ifdef CONFIG_MPU + start = vma->vm_start & PAGE_MASK; + while (start < vma->vm_end) { + protect_page(mm, start, vma->vm_flags); + start += PAGE_SIZE; + } + update_protections(mm); +#endif + mm->map_count++; vma->vm_mm = mm; @@ -707,9 +720,21 @@ static void delete_vma_from_mm(struct vm_area_struct *vma) struct vm_area_struct **pp; struct address_space *mapping; struct mm_struct *mm = vma->vm_mm; +#ifdef CONFIG_MPU + long start; +#endif kenter("%p", vma); +#ifdef CONFIG_MPU + start = vma->vm_start & PAGE_MASK; + while (start < vma->vm_end) { + protect_page(mm, start, 0); + start += PAGE_SIZE; + } + update_protections(mm); +#endif + mm->map_count--; if (mm->mmap_cache == vma) mm->mmap_cache = NULL; -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/