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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 1E5F4C43381 for ; Tue, 5 Mar 2019 21:31:22 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7D6692075B for ; Tue, 5 Mar 2019 21:31:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="fWHZ+oCw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D6692075B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44DVSl3xRszDqJB for ; Wed, 6 Mar 2019 08:31:19 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.b="fWHZ+oCw"; dkim-atps=neutral Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 44DV9w6VFTzDqCt for ; Wed, 6 Mar 2019 08:18:28 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 44DV9l4TCDz9v6LW; Tue, 5 Mar 2019 22:18:19 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=fWHZ+oCw; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id PJ-NwG_4VolX; Tue, 5 Mar 2019 22:18:19 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 44DV9l3DHQz9v6LR; Tue, 5 Mar 2019 22:18:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1551820699; bh=B5ZUuk5B0ViT0jtSlIqHgE+H7PpwgYJZJG3d3EAmQZU=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=fWHZ+oCw2nVvAC6CKstvYu3+p+LeQvOs0nbyd49jliya1w09J+JfBRuu4f0IuF/rd K/4fnOX14cM+5M8DhSgPvG6IMVvcQ+1b0pnMwkbqfz2mBZZg5xOOCyqLLOzhXCsnIg Axx+lSXd/Rmdbs1FcdyVN24mw+2VkcphKTTjWxLs= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 95B048B860; Tue, 5 Mar 2019 22:18:19 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id bgHhWHW6OXtX; Tue, 5 Mar 2019 22:18:19 +0100 (CET) Received: from po16846vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 62B638B83A; Tue, 5 Mar 2019 22:18:19 +0100 (CET) Received: by localhost.localdomain (Postfix, from userid 0) id 068CC6F8CD; Tue, 5 Mar 2019 21:18:18 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH 5/7] powerpc/8xx: Add Kernel Userspace Access Protection To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , ruscur@russell.cc Date: Tue, 5 Mar 2019 21:18:18 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" This patch adds Kernel Userspace Access Protection on the 8xx. When a page is RO or RW, it is set RO or RW for Key 0 and NA for Key 1. Up to now, the User group is defined with Key 0 for both User and Supervisor. By changing the group to Key 0 for User and Key 1 for Supervisor, this patch prevents the Kernel from being able to access user data. At exception entry, the kernel saves SPRN_MD_AP in the regs struct, and reapply the protection. At exception exit it restores SPRN_MD_AP with the value saved on exception entry. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/kup.h | 3 ++ arch/powerpc/include/asm/nohash/32/kup-8xx.h | 52 ++++++++++++++++++++++++++++ arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 7 ++++ arch/powerpc/mm/8xx_mmu.c | 12 +++++++ arch/powerpc/platforms/Kconfig.cputype | 1 + 5 files changed, 75 insertions(+) create mode 100644 arch/powerpc/include/asm/nohash/32/kup-8xx.h diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 51a55be70cbc..2ab9e904c22c 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -5,6 +5,9 @@ #ifdef CONFIG_PPC_BOOK3S_64 #include #endif +#ifdef CONFIG_PPC_8xx +#include +#endif #ifdef __ASSEMBLY__ #ifndef CONFIG_PPC_KUAP diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h new file mode 100644 index 000000000000..dbf0d7d40e7e --- /dev/null +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_KUP_8XX_H_ +#define _ASM_POWERPC_KUP_8XX_H_ + +#include + +#ifdef CONFIG_PPC_KUAP + +#ifdef __ASSEMBLY__ + +.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3 + lis \gpr2, MD_APG_KUAP@h /* only APG0 and APG1 are used */ + mfspr \gpr1, SPRN_MD_AP + mtspr SPRN_MD_AP, \gpr2 + stw \gpr1, STACK_REGS_KUAP(\sp) +.endm + +.macro kuap_restore sp, current, gpr1, gpr2, gpr3 + lwz \gpr1, STACK_REGS_KUAP(\sp) + mtspr SPRN_MD_AP, \gpr1 +.endm + +.macro kuap_check current, gpr +#ifdef CONFIG_PPC_KUAP_DEBUG + mfspr \gpr, SPRN_MD_AP + rlwinm \gpr, \gpr, 16, 0xffff +999: twnei \gpr, MD_APG_KUAP@h + EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) +#endif +.endm + +#else /* !__ASSEMBLY__ */ + +#include + +static inline void allow_user_access(void __user *to, const void __user *from, + unsigned long size) +{ + mtspr(SPRN_MD_AP, MD_APG_INIT); +} + +static inline void prevent_user_access(void __user *to, const void __user *from, + unsigned long size) +{ + mtspr(SPRN_MD_AP, MD_APG_KUAP); +} + +#endif /* !__ASSEMBLY__ */ + +#endif /* CONFIG_PPC_KUAP */ + +#endif /* _ASM_POWERPC_KUP_8XX_H_ */ diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h index 3cb743284e09..f620adef54fc 100644 --- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h @@ -121,6 +121,13 @@ */ #define MD_APG_INIT 0x4fffffff +/* + * 0 => No user => 01 (all accesses performed according to page definition) + * 1 => User => 10 (all accesses performed according to swaped page definition) + * 2-16 => NA => 11 (all accesses performed as user iaw page definition) + */ +#define MD_APG_KUAP 0x6fffffff + /* The effective page number register. When read, contains the information * about the last instruction TLB miss. When MD_RPN is written, bits in * this register are used to create the TLB entry. diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c index e257a0c9bd08..87648b58d295 100644 --- a/arch/powerpc/mm/8xx_mmu.c +++ b/arch/powerpc/mm/8xx_mmu.c @@ -225,3 +225,15 @@ void __init setup_kuep(bool disabled) mtspr(SPRN_MI_AP, MI_APG_KUEP); } #endif + +#ifdef CONFIG_PPC_KUAP +void __init setup_kuap(bool disabled) +{ + pr_info("Activating Kernel Userspace Access Protection\n"); + + if (disabled) + pr_warn("KUAP cannot be disabled yet on 8xx when compiled in\n"); + + mtspr(SPRN_MD_AP, MD_APG_KUAP); +} +#endif diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 00fa0d110dcb..ab586963893a 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -35,6 +35,7 @@ config PPC_8xx select FSL_SOC select SYS_SUPPORTS_HUGETLBFS select PPC_HAVE_KUEP + select PPC_HAVE_KUAP config 40x bool "AMCC 40x" -- 2.13.3