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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 B38FEC47409 for ; Fri, 24 Jan 2020 11:54:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6EEFB2075D for ; Fri, 24 Jan 2020 11:54:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="gf3TbqMx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EEFB2075D 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=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DD5236B000C; Fri, 24 Jan 2020 06:54:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DACC06B000D; Fri, 24 Jan 2020 06:54:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC3506B000E; Fri, 24 Jan 2020 06:54:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0021.hostedemail.com [216.40.44.21]) by kanga.kvack.org (Postfix) with ESMTP id BB2426B000C for ; Fri, 24 Jan 2020 06:54:45 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 7B1AD824556B for ; Fri, 24 Jan 2020 11:54:45 +0000 (UTC) X-FDA: 76412370930.09.fang46_80c7e17f8340b X-HE-Tag: fang46_80c7e17f8340b X-Filterd-Recvd-Size: 6964 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Fri, 24 Jan 2020 11:54:44 +0000 (UTC) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 483yHQ428Pz9tyNC; Fri, 24 Jan 2020 12:54:42 +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=gf3TbqMx; 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 1fODUHn7HhAt; Fri, 24 Jan 2020 12:54:42 +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 483yHQ2zh0z9tyMv; Fri, 24 Jan 2020 12:54:42 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1579866882; bh=JXDaBnd7mgdJWDIpZlE9SEvwyWmEoszznADrTkNkdwM=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=gf3TbqMxn4RpFN3iRulSVmL4SOIOE5qfoyd7wuIo2yD2J3XV0pBONcYt/padeKotW ADF45oxIjvSzVf6rktruAL9T7/Fwj+w67rB/gzC0WshJ/Mad/Azx7x5fyE8/dy+5W1 LpIY/grk/X+52KDi+JmeWtKdVcusrZL/hxD96GZc= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id AC3C98B85C; Fri, 24 Jan 2020 12:54:43 +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 1M8UtqIa11cZ; Fri, 24 Jan 2020 12:54:43 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.111]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 879518B84A; Fri, 24 Jan 2020 12:54:43 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 69317651F0; Fri, 24 Jan 2020 11:54:43 +0000 (UTC) Message-Id: <55bcc1f25d8200892a31f67a0b024ff3b816c3cc.1579866752.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v4 5/7] powerpc/32s: prepare prevent_user_access() for user_access_end() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Date: Fri, 24 Jan 2020 11:54:43 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In preparation of implementing user_access_begin and friends on powerpc, the book3s/32 version of prevent_user_access() need to be prepared for user_access_end(). user_access_end() doesn't provide the address and size which were passed to user_access_begin(), required by prevent_user_access() to know which segment to modify. The list of segments which where unprotected by allow_user_access() are available in current->kuap. But we don't want prevent_user_access() to read this all the time, especially everytime it is 0 (for instance because the access was not a write access). Implement a special direction named KUAP_CURRENT. In this case only, the addr and end are retrieved from current->kuap. Signed-off-by: Christophe Leroy --- v2: No change v3: This patch was not in v3 v4: Added build protection against bad use of KUAP_CURRENT. --- arch/powerpc/include/asm/book3s/32/kup.h | 23 +++++++++++++++---- .../powerpc/include/asm/book3s/64/kup-radix.h | 4 +++- arch/powerpc/include/asm/kup.h | 11 +++++++++ 3 files changed, 32 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index de29fb752cca..17e069291c72 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -108,6 +108,8 @@ static __always_inline void allow_user_access(void __user *to, const void __user u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); + BUILD_BUG_ON(dir == KUAP_CURRENT); + if (!(dir & KUAP_WRITE)) return; @@ -117,6 +119,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user return; end = min(addr + size, TASK_SIZE); + current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */ } @@ -127,15 +130,25 @@ static __always_inline void prevent_user_access(void __user *to, const void __us u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); - if (!(dir & KUAP_WRITE)) - return; - addr = (__force u32)to; + if (dir == KUAP_CURRENT) { + u32 kuap = current->thread.kuap; - if (unlikely(addr >= TASK_SIZE || !size)) + if (unlikely(!kuap)) + return; + + addr = kuap & 0xf0000000; + end = kuap << 28; + } else if (dir & KUAP_WRITE) { + addr = (__force u32)to; + end = min(addr + size, TASK_SIZE); + + if (unlikely(addr >= TASK_SIZE || !size)) + return; + } else { return; + } - end = min(addr + size, TASK_SIZE); current->thread.kuap = 0; kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */ } diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index c8d1076e0ebb..a0263e94df33 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -86,8 +86,10 @@ static __always_inline void allow_user_access(void __user *to, const void __user set_kuap(AMR_KUAP_BLOCK_WRITE); else if (dir == KUAP_WRITE) set_kuap(AMR_KUAP_BLOCK_READ); - else + else if (dir == KUAP_READ_WRITE) set_kuap(0); + else + BUILD_BUG(); } static inline void prevent_user_access(void __user *to, const void __user *from, diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 94f24928916a..c3ce7e8ae9ea 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -5,6 +5,12 @@ #define KUAP_READ 1 #define KUAP_WRITE 2 #define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE) +/* + * For prevent_user_access() only. + * Use the current saved situation instead of the to/from/size params. + * Used on book3s/32 + */ +#define KUAP_CURRENT 4 #ifdef CONFIG_PPC64 #include @@ -88,6 +94,11 @@ static inline void prevent_read_write_user(void __user *to, const void __user *f prevent_user_access(to, from, size, KUAP_READ_WRITE); } +static inline void prevent_current_access_user(void) +{ + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT); +} + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_KUAP_H_ */ -- 2.25.0