From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752789AbcELQjm (ORCPT ); Thu, 12 May 2016 12:39:42 -0400 Received: from mga02.intel.com ([134.134.136.20]:51524 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752689AbcELQjM (ORCPT ); Thu, 12 May 2016 12:39:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,610,1455004800"; d="scan'208";a="804862018" From: Yu-cheng Yu To: linux-kernel@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar Cc: Dave Hansen , Andy Lutomirski , Sai Praneeth Prakhya , "Ravi V. Shankar" , Fenghua Yu , Yu-cheng Yu Subject: [PATCH 4/4] x86/fpu/xstate: Copy xstate registers directly to signal frame when compacted format is in use Date: Thu, 12 May 2016 09:34:24 -0700 Message-Id: <777e1f253275fea5077104150bb4bb4d24a4bc3d.1463070032.git.yu-cheng.yu@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org XSAVES is a kernel instruction and uses a compacted format. When working with user space, the kernel should provide standard-format, non-supervisor state data. We cannot do __copy_to_user() from a compacted-format kernel xstate area to a signal frame. Dave Hansen proposes this method to simplify copy xstate directly to user. Based on an earlier patch from Fenghua Yu Signed-off-by: Yu-cheng Yu Reviewed-by: Dave Hansen --- arch/x86/include/asm/fpu/xstate.h | 1 + arch/x86/kernel/fpu/signal.c | 3 ++- arch/x86/kernel/fpu/xstate.c | 2 +- 3 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 16df2c4..d812cf3 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -47,5 +47,6 @@ extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask); void fpu__xstate_clear_all_cpu_caps(void); void *get_xsave_addr(struct xregs_state *xsave, int xstate); const void *get_xsave_field_ptr(int xstate_field); +int using_compacted_format(void); #endif diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 1454989..9ce2963 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -8,6 +8,7 @@ #include #include #include +#include #include @@ -168,7 +169,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - if (fpregs_active()) { + if (fpregs_active() || using_compacted_format()) { /* Save the live register state to the user directly. */ if (copy_fpregs_to_sigframe(buf_fx)) return -1; diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 5239d4d..e00ec6a 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -420,7 +420,7 @@ static int xfeature_size(int xfeature_nr) * that it is obvious which aspect of 'XSAVES' is being handled * by the calling code. */ -static int using_compacted_format(void) +int using_compacted_format(void) { return cpu_has_xsaves; } -- 1.9.1