Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932679AbbLNTMv (ORCPT ); Mon, 14 Dec 2015 14:12:51 -0500 Received: from mga04.intel.com ([192.55.52.120]:29120 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932077AbbLNTGJ (ORCPT ); Mon, 14 Dec 2015 14:06:09 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,428,1444719600"; d="scan'208";a="707234873" Subject: [PATCH 14/32] 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: Mon, 14 Dec 2015 11:06:07 -0800 References: <20151214190542.39C4886D@viggo.jf.intel.com> In-Reply-To: <20151214190542.39C4886D@viggo.jf.intel.com> Message-Id: <20151214190607.8D59DC37@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2224 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-10-kernel-pkru-instructions arch/x86/include/asm/pgtable.h --- a/arch/x86/include/asm/pgtable.h~pkeys-10-kernel-pkru-instructions 2015-12-14 10:42:44.861895284 -0800 +++ b/arch/x86/include/asm/pgtable.h 2015-12-14 10:42:44.866895508 -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-10-kernel-pkru-instructions arch/x86/include/asm/special_insns.h --- a/arch/x86/include/asm/special_insns.h~pkeys-10-kernel-pkru-instructions 2015-12-14 10:42:44.863895373 -0800 +++ b/arch/x86/include/asm/special_insns.h 2015-12-14 10:42:44.867895553 -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) +{ + u32 ecx = 0; + u32 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/