From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932193AbaGIQIn (ORCPT ); Wed, 9 Jul 2014 12:08:43 -0400 Received: from e28smtp01.in.ibm.com ([122.248.162.1]:52730 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755199AbaGIQIm (ORCPT ); Wed, 9 Jul 2014 12:08:42 -0400 Message-ID: <53BD68FF.7000307@linux.vnet.ibm.com> Date: Wed, 09 Jul 2014 21:38:31 +0530 From: Madhusudanan Kandasamy User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@ozlabs.org CC: linux-kernel@vger.kernel.org Subject: [PATCH] powerpc: Fail remap_4k_pfn() if PFN doesn't fit inside PTE Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14070916-4790-0000-0000-0000028DF306 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org remap_4k_pfn() silently truncates upper bits of input 4K PFN if it cannot be contained in PTE. This leads invalid memory mapping and could result in a system crash when the memory is accessed. This patch fails remap_4k_pfn() and returns -EINVAL if the input 4K PFN cannot be contained in PTE. Used a helper inline function in the failure case so that the remap_4k_pfn() macro can still be used in expression contexts. Signed-off-by: Madhusudanan Kandasamy --- arch/powerpc/include/asm/pte-hash64-64k.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/pte-hash64-64k.h b/arch/powerpc/include/asm/pte-hash64-64k.h index d836d94..10af7f1 100644 --- a/arch/powerpc/include/asm/pte-hash64-64k.h +++ b/arch/powerpc/include/asm/pte-hash64-64k.h @@ -74,8 +74,15 @@ #define pte_pagesize_index(mm, addr, pte) \ (((pte) & _PAGE_COMBO)? MMU_PAGE_4K: MMU_PAGE_64K) +static inline int bad_4k_pfn(void) +{ + WARN_ON(1); + return -EINVAL; +} + #define remap_4k_pfn(vma, addr, pfn, prot) \ - remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \ - __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN)) + ((pfn >= (1UL << (64 - PTE_RPN_SHIFT))) ? bad_4k_pfn() : \ + remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, \ + __pgprot(pgprot_val((prot)) | _PAGE_4K_PFN))) #endif /* __ASSEMBLY__ */ -- 2.0.1