Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756198AbdGKSLG (ORCPT ); Tue, 11 Jul 2017 14:11:06 -0400 Received: from mga09.intel.com ([134.134.136.24]:9627 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755947AbdGKSLE (ORCPT ); Tue, 11 Jul 2017 14:11:04 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,347,1496127600"; d="scan'208";a="123902703" Subject: Re: [RFC v5 11/38] mm: introduce an additional vma bit for powerpc pkey To: Ram Pai , 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 References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> <1499289735-14220-12-git-send-email-linuxram@us.ibm.com> Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com From: Dave Hansen Message-ID: <290636b0-aafd-9bcd-d309-4cff41ce923c@intel.com> Date: Tue, 11 Jul 2017 11:10:46 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1499289735-14220-12-git-send-email-linuxram@us.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3270 Lines: 84 On 07/05/2017 02:21 PM, Ram Pai wrote: > Currently there are only 4bits in the vma flags to support 16 keys > on x86. powerpc supports 32 keys, which needs 5bits. This patch > introduces an addition bit in the vma flags. > > Signed-off-by: Ram Pai > --- > fs/proc/task_mmu.c | 6 +++++- > include/linux/mm.h | 18 +++++++++++++----- > 2 files changed, 18 insertions(+), 6 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index f0c8b33..2ddc298 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -666,12 +666,16 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) > [ilog2(VM_MERGEABLE)] = "mg", > [ilog2(VM_UFFD_MISSING)]= "um", > [ilog2(VM_UFFD_WP)] = "uw", > -#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS > +#ifdef CONFIG_ARCH_HAS_PKEYS > /* These come out via ProtectionKey: */ > [ilog2(VM_PKEY_BIT0)] = "", > [ilog2(VM_PKEY_BIT1)] = "", > [ilog2(VM_PKEY_BIT2)] = "", > [ilog2(VM_PKEY_BIT3)] = "", > +#endif /* CONFIG_ARCH_HAS_PKEYS */ > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS > + /* Additional bit in ProtectionKey: */ > + [ilog2(VM_PKEY_BIT4)] = "", > #endif I'd probably just leave the #ifdef out and eat the byte or whatever of storage that this costs us on x86. > }; > size_t i; > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 7cb17c6..3d35bcc 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -208,21 +208,29 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *, > #define VM_HIGH_ARCH_BIT_1 33 /* bit only usable on 64-bit architectures */ > #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ > #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ > +#define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit arch */ Please just copy the above lines. > #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) > #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) > #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) > #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) > +#define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) > #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ > > -#if defined(CONFIG_X86) > -# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ > -#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) > +#ifdef CONFIG_ARCH_HAS_PKEYS > # define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 > -# define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ > +# define VM_PKEY_BIT0 VM_HIGH_ARCH_0 > # define VM_PKEY_BIT1 VM_HIGH_ARCH_1 > # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 > # define VM_PKEY_BIT3 VM_HIGH_ARCH_3 > -#endif > +#endif /* CONFIG_ARCH_HAS_PKEYS */ We have the space here, so can we just say that it's 4-bits on x86 and 5 on ppc? > +#if defined(CONFIG_PPC64_MEMORY_PROTECTION_KEYS) > +# define VM_PKEY_BIT4 VM_HIGH_ARCH_4 /* additional key bit used on ppc64 */ > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ Why bother #ifdef'ing a #define? > +#if defined(CONFIG_X86) > +# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ > #elif defined(CONFIG_PPC) > # define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */ > #elif defined(CONFIG_PARISC) >