From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752038AbdIXK7o (ORCPT ); Sun, 24 Sep 2017 06:59:44 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:38239 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908AbdIXK7j (ORCPT ); Sun, 24 Sep 2017 06:59:39 -0400 X-Google-Smtp-Source: AOwi7QBC8D8Lx21kXtfkX8fXE7PI4cAUMj65D0Ww+dk4wiit8XAoaSs9NrObfDXZXTYYDYnChX1DMQ== From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Eric Biggers , Andy Lutomirski , Borislav Petkov , Dave Hansen , Fenghua Yu , "H . Peter Anvin" , Linus Torvalds , Oleg Nesterov , Peter Zijlstra , Rik van Riel , Thomas Gleixner , Yu-cheng Yu Subject: [PATCH 05/10] x86/fpu: Eliminate the 'xfeatures' local variable in copy_kernel_to_xstate() Date: Sun, 24 Sep 2017 12:59:08 +0200 Message-Id: <20170924105913.9157-6-mingo@kernel.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170924105913.9157-1-mingo@kernel.org> References: <20170924105913.9157-1-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Biggers We have this information in the xstate_header. Signed-off-by: Eric Biggers Cc: Andy Lutomirski Cc: Dave Hansen Cc: Dmitry Vyukov Cc: Fenghua Yu Cc: Kees Cook Cc: Kevin Hao Cc: Linus Torvalds Cc: Michael Halcrow Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Wanpeng Li Cc: Yu-cheng Yu Cc: kernel-hardening@lists.openwall.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/xstate.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 02591b96bb25..c97c4a9db52a 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1146,7 +1146,6 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) { unsigned int offset, size; int i; - u64 xfeatures; u64 allowed_features; struct xstate_header hdr; @@ -1154,20 +1153,19 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) size = sizeof(hdr); memcpy(&hdr, kbuf + offset, size); - xfeatures = hdr.xfeatures; /* * Reject if the user sets any disabled or supervisor features: */ allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR; - if (xfeatures & ~allowed_features) + if (hdr.xfeatures & ~allowed_features) return -EINVAL; for (i = 0; i < XFEATURE_MAX; i++) { u64 mask = ((u64)1 << i); - if (xfeatures & mask) { + if (hdr.xfeatures & mask) { void *dst = __raw_xsave_addr(xsave, 1 << i); offset = xstate_offsets[i]; @@ -1177,7 +1175,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) } } - if (xfeatures_mxcsr_quirk(xfeatures)) { + if (xfeatures_mxcsr_quirk(hdr.xfeatures)) { offset = offsetof(struct fxregs_state, mxcsr); size = MXCSR_AND_FLAGS_SIZE; memcpy(&xsave->i387.mxcsr, kbuf + offset, size); @@ -1192,7 +1190,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) /* * Add back in the features that came in from userspace: */ - xsave->header.xfeatures |= xfeatures; + xsave->header.xfeatures |= hdr.xfeatures; return 0; } -- 2.11.0