From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030946AbcGKQOX (ORCPT ); Mon, 11 Jul 2016 12:14:23 -0400 Received: from terminus.zytor.com ([198.137.202.10]:50244 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030843AbcGKQOV (ORCPT ); Mon, 11 Jul 2016 12:14:21 -0400 Date: Mon, 11 Jul 2016 09:13:50 -0700 From: tip-bot for Yu-cheng Yu Message-ID: Cc: fenghua.yu@intel.com, ravi.v.shankar@intel.com, mingo@kernel.org, tglx@linutronix.de, yu-cheng.yu@intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, dave.hansen@intel.com, peterz@infradead.org, h.peter.anvin@intel.com, torvalds@linux-foundation.org Reply-To: fenghua.yu@intel.com, tglx@linutronix.de, mingo@kernel.org, ravi.v.shankar@intel.com, dave.hansen@intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, yu-cheng.yu@intel.com, torvalds@linux-foundation.org, h.peter.anvin@intel.com, peterz@infradead.org In-Reply-To: <1468253937-40008-4-git-send-email-fenghua.yu@intel.com> References: <1468253937-40008-4-git-send-email-fenghua.yu@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/fpu] x86/fpu/xstate: Fix fpstate_init() for XRSTORS Git-Commit-ID: 35ac2d7ba787eb4b7418a5a6f5919c25e10a780a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 35ac2d7ba787eb4b7418a5a6f5919c25e10a780a Gitweb: http://git.kernel.org/tip/35ac2d7ba787eb4b7418a5a6f5919c25e10a780a Author: Yu-cheng Yu AuthorDate: Mon, 11 Jul 2016 09:18:56 -0700 Committer: Ingo Molnar CommitDate: Mon, 11 Jul 2016 16:44:00 +0200 x86/fpu/xstate: Fix fpstate_init() for XRSTORS In XSAVES mode if fpstate_init() is used to initialize a task's extended state area, xsave.header.xcomp_bv[63] must be set. Otherwise, when the task is scheduled, a warning is triggered from copy_kernel_to_xregs(). One such test case is: setting an invalid extended state through PTRACE. When xstateregs_set() rejects the syscall and re-initializes the task's extended state area. This triggers the warning mentioned above. Signed-off-by: Yu-cheng Yu Signed-off-by: Fenghua Yu Reviewed-by: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Ravi V Shankar Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1468253937-40008-4-git-send-email-fenghua.yu@intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/types.h | 6 ++++++ arch/x86/kernel/fpu/core.c | 8 ++++++++ 2 files changed, 14 insertions(+) diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 12dd648..48df486 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -232,6 +232,12 @@ struct xstate_header { } __attribute__((packed)); /* + * xstate_header.xcomp_bv[63] indicates that the extended_state_area + * is in compacted format. + */ +#define XCOMP_BV_COMPACTED_FORMAT ((u64)1 << 63) + +/* * This is our most modern FPU state format, as saved by the XSAVE * and restored by the XRSTOR instructions. * diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index c759bd0..3fc03a0 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -229,6 +230,13 @@ void fpstate_init(union fpregs_state *state) memset(state, 0, fpu_kernel_xstate_size); + /* + * XRSTORS requires that this bit is set in xcomp_bv, or + * it will #GP. Make sure it is replaced after the memset(). + */ + if (static_cpu_has(X86_FEATURE_XSAVES)) + state->xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT; + if (static_cpu_has(X86_FEATURE_FXSR)) fpstate_init_fxstate(&state->fxsave); else