From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id 71FEC6B0069 for ; Wed, 1 Feb 2017 18:24:11 -0500 (EST) Received: by mail-pg0-f69.google.com with SMTP id 75so505808166pgf.3 for ; Wed, 01 Feb 2017 15:24:11 -0800 (PST) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTPS id s5si15694846pgj.385.2017.02.01.15.24.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Feb 2017 15:24:10 -0800 (PST) Subject: [RFC][PATCH 1/7] x86, mpx: introduce per-mm MPX table size tracking From: Dave Hansen Date: Wed, 01 Feb 2017 15:24:09 -0800 References: <20170201232408.FA486473@viggo.jf.intel.com> In-Reply-To: <20170201232408.FA486473@viggo.jf.intel.com> Message-Id: <20170201232409.B089D5ED@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, kirill.shutemov@linux.intel.com, Dave Hansen Larger address spaces mean larger MPX bounds table sizes. This tracks which size tables we are using. "MAWA" is what the hardware documentation calls this feature: MPX Address-Width Adjust. --- b/arch/x86/include/asm/mmu.h | 1 + b/arch/x86/include/asm/mpx.h | 6 ++++++ 2 files changed, 7 insertions(+) diff -puN arch/x86/include/asm/mmu.h~mawa-020-mmu_context-mawa arch/x86/include/asm/mmu.h --- a/arch/x86/include/asm/mmu.h~mawa-020-mmu_context-mawa 2017-02-01 15:12:15.699124140 -0800 +++ b/arch/x86/include/asm/mmu.h 2017-02-01 15:12:15.702124275 -0800 @@ -34,6 +34,7 @@ typedef struct { #ifdef CONFIG_X86_INTEL_MPX /* address of the bounds directory */ void __user *bd_addr; + int mpx_bd_shift; #endif } mm_context_t; diff -puN arch/x86/include/asm/mpx.h~mawa-020-mmu_context-mawa arch/x86/include/asm/mpx.h --- a/arch/x86/include/asm/mpx.h~mawa-020-mmu_context-mawa 2017-02-01 15:12:15.700124185 -0800 +++ b/arch/x86/include/asm/mpx.h 2017-02-01 15:12:15.702124275 -0800 @@ -68,6 +68,12 @@ static inline void mpx_mm_init(struct mm * directory, so point this at an invalid address. */ mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR; + /* + * All processes start out in "legacy" MPX mode with + * the old bounds directory size. This corresponds to + * what the specs call MAWA=0. + */ + mm->context.mpx_bd_shift = 0; } void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long start, unsigned long end); _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org