From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755365AbdGKLYJ (ORCPT ); Tue, 11 Jul 2017 07:24:09 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48614 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175AbdGKLYH (ORCPT ); Tue, 11 Jul 2017 07:24:07 -0400 Subject: Re: [RFC v5 31/38] powerpc: introduce get_pte_pkey() helper To: Ram Pai , Anshuman Khandual References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> <1499289735-14220-32-git-send-email-linuxram@us.ibm.com> <58e0d9ff-727f-c960-5c5f-16d19a89e181@linux.vnet.ibm.com> <20170710055502.GC5713@ram.oc3035372033.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com From: Anshuman Khandual Date: Tue, 11 Jul 2017 16:52:40 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170710055502.GC5713@ram.oc3035372033.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable x-cbid: 17071111-0004-0000-0000-000002269370 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17071111-0005-0000-0000-00005E0B029F Message-Id: <94b76f58-1002-b3a7-7269-67129c795f25@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-11_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1707110180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/10/2017 11:25 AM, Ram Pai wrote: > On Mon, Jul 10, 2017 at 08:41:30AM +0530, Anshuman Khandual wrote: >> On 07/06/2017 02:52 AM, Ram Pai wrote: >>> get_pte_pkey() helper returns the pkey associated with >>> a address corresponding to a given mm_struct. >>> >>> Signed-off-by: Ram Pai >>> --- >>> arch/powerpc/include/asm/book3s/64/mmu-hash.h | 5 ++++ >>> arch/powerpc/mm/hash_utils_64.c | 28 +++++++++++++++++++++++++ >>> 2 files changed, 33 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> index f7a6ed3..369f9ff 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h >>> @@ -450,6 +450,11 @@ extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap, >>> int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, >>> pte_t *ptep, unsigned long trap, unsigned long flags, >>> int ssize, unsigned int shift, unsigned int mmu_psize); >>> + >>> +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS >>> +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address); >>> +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ >>> + >>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >>> extern int __hash_page_thp(unsigned long ea, unsigned long access, >>> unsigned long vsid, pmd_t *pmdp, unsigned long trap, >>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c >>> index 1e74529..591990c 100644 >>> --- a/arch/powerpc/mm/hash_utils_64.c >>> +++ b/arch/powerpc/mm/hash_utils_64.c >>> @@ -1573,6 +1573,34 @@ void hash_preload(struct mm_struct *mm, unsigned long ea, >>> local_irq_restore(flags); >>> } >>> >>> +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS >>> +/* >>> + * return the protection key associated with the given address >>> + * and the mm_struct. >>> + */ >>> +u16 get_pte_pkey(struct mm_struct *mm, unsigned long address) >>> +{ >>> + pte_t *ptep; >>> + u16 pkey = 0; >>> + unsigned long flags; >>> + >>> + if (REGION_ID(address) == VMALLOC_REGION_ID) >>> + mm = &init_mm; >> >> IIUC, protection keys are only applicable for user space. This >> function is getting used to populate siginfo structure. Then how >> can we ever request this for any address in VMALLOC region. > > make sense. this check is not needed. > >> >>> + >>> + if (!mm || !mm->pgd) >>> + return 0; >> >> Is this really required at this stage ? > > its a sanity check to gaurd against bad inputs. See a problem? I mean its okay, thought it to be unnecessary. Your call.