From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x7Sm85r4czDqk7 for ; Thu, 13 Jul 2017 17:55:20 +1000 (AEST) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v6D7rgG9033908 for ; Thu, 13 Jul 2017 03:55:18 -0400 Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bnt3pcq6u-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 13 Jul 2017 03:55:18 -0400 Received: from localhost by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 13 Jul 2017 01:55:17 -0600 Date: Thu, 13 Jul 2017 00:55:02 -0700 From: Ram Pai To: Balbir Singh 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, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com Subject: Re: [RFC v5 15/38] powerpc: helper function to read,write AMR,IAMR,UAMOR registers Reply-To: Ram Pai References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> <1499289735-14220-16-git-send-email-linuxram@us.ibm.com> <20170712152601.3b2f52ed@firefly.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170712152601.3b2f52ed@firefly.ozlabs.ibm.com> Message-Id: <20170713075502.GG5525@ram.oc3035372033.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jul 12, 2017 at 03:26:01PM +1000, Balbir Singh wrote: > On Wed, 5 Jul 2017 14:21:52 -0700 > Ram Pai wrote: > > > Implements helper functions to read and write the key related > > registers; AMR, IAMR, UAMOR. > > > > AMR register tracks the read,write permission of a key > > IAMR register tracks the execute permission of a key > > UAMOR register enables and disables a key > > > > Signed-off-by: Ram Pai > > --- > > arch/powerpc/include/asm/book3s/64/pgtable.h | 60 ++++++++++++++++++++++++++ > > 1 files changed, 60 insertions(+), 0 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > > index 85bc987..435d6a7 100644 > > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > > @@ -428,6 +428,66 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, > > pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1); > > } > > > > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > > + > > +#include > > +static inline u64 read_amr(void) > > +{ > > + return mfspr(SPRN_AMR); > > +} > > +static inline void write_amr(u64 value) > > +{ > > + mtspr(SPRN_AMR, value); > > +} > > +static inline u64 read_iamr(void) > > +{ > > + return mfspr(SPRN_IAMR); > > +} > > +static inline void write_iamr(u64 value) > > +{ > > + mtspr(SPRN_IAMR, value); > > +} > > +static inline u64 read_uamor(void) > > +{ > > + return mfspr(SPRN_UAMOR); > > +} > > +static inline void write_uamor(u64 value) > > +{ > > + mtspr(SPRN_UAMOR, value); > > +} > > + > > +#else /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ > > + > > +static inline u64 read_amr(void) > > +{ > > + WARN(1, "%s called with MEMORY PROTECTION KEYS disabled\n", __func__); > > + return -1; > > +} > > Why do we need to have a version here if we are going to WARN(), why not > let the compilation fail if called from outside of CONFIG_PPC64_MEMORY_PROTECTION_KEYS? > Is that the intention? I did not want to stop someone; kernel module for example, from calling these interfaces from outside the pkey domain. Either way can be argued to be correct, I suppose. RP