From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754130AbbCBSel (ORCPT ); Mon, 2 Mar 2015 13:34:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52768 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660AbbCBSej (ORCPT ); Mon, 2 Mar 2015 13:34:39 -0500 Date: Mon, 2 Mar 2015 19:32:37 +0100 From: Oleg Nesterov To: Tavis Ormandy , Borislav Petkov , Ingo Molnar Cc: Rik van Riel , Andy Lutomirski , Linus Torvalds , linux-kernel@vger.kernel.org Subject: [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Message-ID: <20150302183237.GB23085@redhat.com> References: <20150301184650.GA12758@redhat.com> <20150301185943.GA14318@redhat.com> <20150302174818.GA16886@redhat.com> <20150302183210.GA23085@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150302183210.GA23085@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cosmetic. xstateregs_get() and xstateregs_set() abuse ->fxsave to access xsave->i387.sw_reserved. This is correct, ->fxsave and xsave->i387 share the same memory, but imho this looks confusing. And we can make this code more readable if we add "struct xsave_struct *" local. Signed-off-by: Oleg Nesterov --- arch/x86/kernel/i387.c | 25 +++++++++---------------- 1 files changed, 9 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 8e070a6..4b12df8 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -339,6 +339,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf) { + struct xsave_struct *xsave = &target->thread.fpu.state->xsave; int ret; if (!cpu_has_xsave) @@ -353,14 +354,12 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, * memory layout in the thread struct, so that we can copy the entire * xstateregs to the user using one user_regset_copyout(). */ - memcpy(&target->thread.fpu.state->fxsave.sw_reserved, - xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes)); - + memcpy(&xsave->i387.sw_reserved, + xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes)); /* * Copy the xstate memory layout. */ - ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu.state->xsave, 0, -1); + ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); return ret; } @@ -368,8 +367,8 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { + struct xsave_struct *xsave = &target->thread.fpu.state->xsave; int ret; - struct xsave_hdr_struct *xsave_hdr; if (!cpu_has_xsave) return -ENODEV; @@ -378,22 +377,16 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; - ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu.state->xsave, 0, -1); - + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); /* * mxcsr reserved bits must be masked to zero for security reasons. */ - target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask; - - xsave_hdr = &target->thread.fpu.state->xsave.xsave_hdr; - - xsave_hdr->xstate_bv &= pcntxt_mask; + xsave->i387.mxcsr &= mxcsr_feature_mask; + xsave->xsave_hdr.xstate_bv &= pcntxt_mask; /* * These bits must be zero. */ - memset(xsave_hdr->reserved, 0, 48); - + memset(&xsave->xsave_hdr.reserved, 0, 48); return ret; } -- 1.5.5.1