From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755163AbaDGL2d (ORCPT ); Mon, 7 Apr 2014 07:28:33 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:55641 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753510AbaDGL2a (ORCPT ); Mon, 7 Apr 2014 07:28:30 -0400 Message-ID: <53428BC9.3070001@gmail.com> Date: Mon, 07 Apr 2014 19:28:09 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Guan Xuetao CC: akpm@linux-foundation.org, liuj97@gmail.com, rientjes@google.com, dhowells@redhat.com, mhocko@suse.cz, mgorman@suse.de, "linux-kernel@vger.kernel.org" Subject: [PATCH] arch:unicore32:mm: add devmem_is_allowed() to support STRICT_DEVMEM Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org unicore32 supports STRICT_DEVMEM, so it needs devmem_is_allowed(), like some of other architectures have done (e.g. arm, powerpc, x86 ...). The related error with allmodconfig: CC drivers/char/mem.o drivers/char/mem.c: In function ‘range_is_allowed’: drivers/char/mem.c:69: error: implicit declaration of function ‘devmem_is_allowed’ make[2]: *** [drivers/char/mem.o] Error 1 make[1]: *** [drivers/char] Error 2 make: *** [drivers] Error 2 Signed-off-by: Chen Gang --- arch/unicore32/include/asm/page.h | 4 ++++ arch/unicore32/mm/init.c | 18 ++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/arch/unicore32/include/asm/page.h b/arch/unicore32/include/asm/page.h index 594b322..231cb89 100644 --- a/arch/unicore32/include/asm/page.h +++ b/arch/unicore32/include/asm/page.h @@ -68,6 +68,10 @@ typedef struct page *pgtable_t; extern int pfn_valid(unsigned long); +#ifdef CONFIG_STRICT_DEVMEM +extern int devmem_is_allowed(unsigned long pfn); +#endif /* CONFIG_STRICT_DEVMEM */ + #include #endif /* !__ASSEMBLY__ */ diff --git a/arch/unicore32/mm/init.c b/arch/unicore32/mm/init.c index be2bde9..3bc3a59 100644 --- a/arch/unicore32/mm/init.c +++ b/arch/unicore32/mm/init.c @@ -449,3 +449,21 @@ static int __init keepinitrd_setup(char *__unused) __setup("keepinitrd", keepinitrd_setup); #endif + +#ifdef CONFIG_STRICT_DEVMEM +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain + * address is valid. The argument is a physical page number. + * We mimic x86 here by disallowing access to system RAM as well as + * device-exclusive MMIO regions. This effectively disable read()/write() + * on /dev/mem. + */ +int devmem_is_allowed(unsigned long pfn) +{ + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pfn)) + return 1; + return 0; +} +#endif /* CONFIG_STRICT_DEVMEM */ -- 1.7.9.5