Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752463AbbEGRmo (ORCPT ); Thu, 7 May 2015 13:42:44 -0400 Received: from mga11.intel.com ([192.55.52.93]:39318 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751967AbbEGRlb (ORCPT ); Thu, 7 May 2015 13:41:31 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,384,1427785200"; d="scan'208";a="722360720" Subject: [PATCH 06/12] x86, pkeys: store protection in high VMA flags To: dave@sr71.net Cc: linux-kernel@vger.kernel.org, x86@kernel.org From: Dave Hansen Date: Thu, 07 May 2015 10:41:34 -0700 References: <20150507174132.34AF8FAF@viggo.jf.intel.com> In-Reply-To: <20150507174132.34AF8FAF@viggo.jf.intel.com> Message-Id: <20150507174134.49B148E4@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2703 Lines: 66 vma->vm_flags is an 'unsigned long', so has space for 32 flags on 32-bit architectures. The high 32 bits are unused on 64-bit platforms. We've steered away from using the unused high VMA bits for things because we would have difficulty supporting it on 32-bit. Protection Keys are not available in 32-bit mode, so there is no concern about supporting this feature in 32-bit mode or on 32-bit CPUs. This patch carves out 4 bits from the high half of vma->vm_flags and allows architectures to set config option to make them available. --- b/arch/x86/Kconfig | 1 + b/include/linux/mm.h | 7 +++++++ b/mm/Kconfig | 3 +++ 3 files changed, 11 insertions(+) diff -puN arch/x86/Kconfig~pkeys-7-eat-high-vma-flags arch/x86/Kconfig --- a/arch/x86/Kconfig~pkeys-7-eat-high-vma-flags 2015-05-07 10:31:42.943257595 -0700 +++ b/arch/x86/Kconfig 2015-05-07 10:31:42.951257956 -0700 @@ -142,6 +142,7 @@ config X86 select ACPI_LEGACY_TABLES_LOOKUP if ACPI select X86_FEATURE_NAMES if PROC_FS select SRCU + select ARCH_USES_HIGH_VMA_FLAGS if X86_64 config INSTRUCTION_DECODER def_bool y diff -puN include/linux/mm.h~pkeys-7-eat-high-vma-flags include/linux/mm.h --- a/include/linux/mm.h~pkeys-7-eat-high-vma-flags 2015-05-07 10:31:42.945257685 -0700 +++ b/include/linux/mm.h 2015-05-07 10:31:42.951257956 -0700 @@ -153,6 +153,13 @@ extern unsigned int kobjsize(const void #define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */ #define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */ +#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS +#define VM_HIGH_ARCH_1 0x100000000 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_2 0x200000000 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_3 0x400000000 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_4 0x800000000 /* bit only usable on 64-bit architectures */ +#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ + #if defined(CONFIG_X86) # define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) diff -puN mm/Kconfig~pkeys-7-eat-high-vma-flags mm/Kconfig --- a/mm/Kconfig~pkeys-7-eat-high-vma-flags 2015-05-07 10:31:42.947257775 -0700 +++ b/mm/Kconfig 2015-05-07 10:31:42.952258001 -0700 @@ -635,3 +635,6 @@ config MAX_STACK_SIZE_MB changed to a smaller value in which case that is used. A sane initial value is 80 MB. + +config ARCH_USES_HIGH_VMA_FLAGS + bool _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/