From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7B2DC41514 for ; Sun, 1 Sep 2019 15:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A79DF2342C for ; Sun, 1 Sep 2019 15:45:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728687AbfIAPpj (ORCPT ); Sun, 1 Sep 2019 11:45:39 -0400 Received: from ste-pvt-msa2.bahnhof.se ([213.80.101.71]:37489 "EHLO ste-pvt-msa2.bahnhof.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728621AbfIAPpj (ORCPT ); Sun, 1 Sep 2019 11:45:39 -0400 Received: from localhost (localhost [127.0.0.1]) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTP id D0F9B3F9E4; Sun, 1 Sep 2019 17:37:36 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from ste-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (ste-ftg-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id btzH-vP_3bIy; Sun, 1 Sep 2019 17:37:36 +0200 (CEST) Received: from localhost (h-41-252.A163.priv.bahnhof.se [46.59.41.252]) (Authenticated sender: mb547485) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id 173B13F9CE; Sun, 1 Sep 2019 17:37:36 +0200 (CEST) Date: Sun, 1 Sep 2019 17:37:35 +0200 From: Fredrik Noring To: Paul Burton , linux-mips@vger.kernel.org Cc: "Maciej W. Rozycki" , =?utf-8?Q?J=C3=BCrgen?= Urban Subject: [PATCH 004/120] MIPS: R5900: Reset bits 127..64 of GPRs in RESTORE_SOME Message-ID: <810f5e4de4a5d600a013733c9c13c7aa0b8c30d5.1567326213.git.noring@nocrew.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Bits 127..64 are not used by the kernel but can be modified by applications using the R5900 specific multimedia instructions. Clearing them in RESTORE_SOME prevents leaking information between processes. This is a provisional measure until full 128-bit registers are saved/restored, possibly using SQ/LQ. Signed-off-by: Fredrik Noring --- As mentioned in the cover letter, I think it would be much better to save and restore 128-bit GPRs here. --- arch/mips/include/asm/stackframe.h | 53 ++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h index 4d6ad907ae54..aaed9b522220 100644 --- a/arch/mips/include/asm/stackframe.h +++ b/arch/mips/include/asm/stackframe.h @@ -349,6 +349,58 @@ cfi_ld sp, PT_R29, \docfi .endm +#ifdef CONFIG_CPU_R5900 + /* + * Reset bits 127..64 of 128-bit multimedia registers. + * + * Bits 127..64 are not used by the kernel but can be modified + * by applications using the R5900 specific multimedia + * instructions. Clearing them prevents leaking information + * between processes. This is a provisional measure until full + * 128-bit registers are saved/restored, possibly using SQ/LQ. + */ + .macro RESET_MMR + .set push + .set noreorder + .set noat + pcpyld $1, $0, $1 + pcpyld $2, $0, $2 + pcpyld $3, $0, $3 + pcpyld $4, $0, $4 + pcpyld $5, $0, $5 + pcpyld $6, $0, $6 + pcpyld $7, $0, $7 + pcpyld $8, $0, $8 + pcpyld $9, $0, $9 + pcpyld $10, $0, $10 + pcpyld $11, $0, $11 + pcpyld $12, $0, $12 + pcpyld $13, $0, $13 + pcpyld $14, $0, $14 + pcpyld $15, $0, $15 + pcpyld $16, $0, $16 + pcpyld $17, $0, $17 + pcpyld $18, $0, $18 + pcpyld $19, $0, $19 + pcpyld $20, $0, $20 + pcpyld $21, $0, $21 + pcpyld $22, $0, $22 + pcpyld $23, $0, $23 + pcpyld $24, $0, $24 + pcpyld $25, $0, $25 + pcpyld $26, $0, $26 + pcpyld $27, $0, $27 + pcpyld $28, $0, $28 + pcpyld $29, $0, $29 + pcpyld $30, $0, $30 + pcpyld $31, $0, $31 + .set pop + .endm +#else + .macro RESET_MMR + .endm +#endif + #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) .macro RESTORE_SOME docfi=0 @@ -393,6 +445,7 @@ .set push .set reorder .set noat + RESET_MMR mfc0 a0, CP0_STATUS ori a0, STATMASK xori a0, STATMASK -- 2.21.0