Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754944AbbLDBUj (ORCPT ); Thu, 3 Dec 2015 20:20:39 -0500 Received: from mga03.intel.com ([134.134.136.65]:16394 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754706AbbLDBOp (ORCPT ); Thu, 3 Dec 2015 20:14:45 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,378,1444719600"; d="scan'208";a="853564985" Subject: [PATCH 14/34] x86, pkeys: add functions to fetch PKRU To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen Date: Thu, 03 Dec 2015 17:14:44 -0800 References: <20151204011424.8A36E365@viggo.jf.intel.com> In-Reply-To: <20151204011424.8A36E365@viggo.jf.intel.com> Message-Id: <20151204011444.526641BA@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2242 Lines: 71 From: Dave Hansen This adds the raw instruction to access PKRU as well as some accessor functions that correctly handle when the CPU does not support the instruction. We don't use it here, but we will use read_pkru() in the next patch. Signed-off-by: Dave Hansen --- b/arch/x86/include/asm/pgtable.h | 8 ++++++++ b/arch/x86/include/asm/special_insns.h | 22 ++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff -puN arch/x86/include/asm/pgtable.h~pkeys-13-kernel-pkru-instructions arch/x86/include/asm/pgtable.h --- a/arch/x86/include/asm/pgtable.h~pkeys-13-kernel-pkru-instructions 2015-12-03 16:21:24.298611081 -0800 +++ b/arch/x86/include/asm/pgtable.h 2015-12-03 16:21:24.303611308 -0800 @@ -102,6 +102,14 @@ static inline int pte_dirty(pte_t pte) return pte_flags(pte) & _PAGE_DIRTY; } + +static inline u32 read_pkru(void) +{ + if (boot_cpu_has(X86_FEATURE_OSPKE)) + return __read_pkru(); + return 0; +} + static inline int pte_young(pte_t pte) { return pte_flags(pte) & _PAGE_ACCESSED; diff -puN arch/x86/include/asm/special_insns.h~pkeys-13-kernel-pkru-instructions arch/x86/include/asm/special_insns.h --- a/arch/x86/include/asm/special_insns.h~pkeys-13-kernel-pkru-instructions 2015-12-03 16:21:24.300611172 -0800 +++ b/arch/x86/include/asm/special_insns.h 2015-12-03 16:21:24.303611308 -0800 @@ -98,6 +98,28 @@ static inline void native_write_cr8(unsi } #endif +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +static inline u32 __read_pkru(void) +{ + unsigned int ecx = 0; + unsigned int edx, pkru; + + /* + * "rdpkru" instruction. Places PKRU contents in to EAX, + * clears EDX and requires that ecx=0. + */ + asm volatile(".byte 0x0f,0x01,0xee\n\t" + : "=a" (pkru), "=d" (edx) + : "c" (ecx)); + return pkru; +} +#else +static inline u32 __read_pkru(void) +{ + return 0; +} +#endif + static inline void native_wbinvd(void) { asm volatile("wbinvd": : :"memory"); _ -- 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/