From patchwork Thu Jan 23 12:59:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 11347739 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1B01092A for ; Thu, 23 Jan 2020 13:00:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E31FD2467B for ; Thu, 23 Jan 2020 13:00:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="FrIBpB+S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729021AbgAWNAJ (ORCPT ); Thu, 23 Jan 2020 08:00:09 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:63707 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728811AbgAWNAA (ORCPT ); Thu, 23 Jan 2020 08:00:00 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 483Mn85D26z9vB4k; Thu, 23 Jan 2020 13:59:56 +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=FrIBpB+S; 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 MTbpDlw4sfRu; Thu, 23 Jan 2020 13:59:56 +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 483Mn847xRz9vB4X; Thu, 23 Jan 2020 13:59:56 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1579784396; bh=Vfl0AOa1Mdh0VxoIajIH2/Esuy8toZoWQbvUL/0X23U=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=FrIBpB+SvgnON+NoB08b4tmtV/gabjQ+QjDlgAVWzVfpJ4Rwaw56UVOygjP39m9l3 3S1JVj7pFA7m8SULhfKcZQCjXxL83qnG9/i5HYVNGJlg59WK54M85n9faaXoVT3OEt +7aK2mr/N/s1Hseu2VJcRpJbKhb5gmMgurZg45jM= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id CFF0C8B82E; Thu, 23 Jan 2020 13:59:57 +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 MYYQpzE1hRXB; Thu, 23 Jan 2020 13:59:57 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 880168B82C; Thu, 23 Jan 2020 13:59:57 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 5DE51651C0; Thu, 23 Jan 2020 12:59:57 +0000 (UTC) Message-Id: <408c90c4068b00ea8f1c41cca45b84ec23d4946b.1579783936.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v3 6/7] powerpc/32s: Prepare allow_user_access() for user_access_begin() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Date: Thu, 23 Jan 2020 12:59:57 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In preparation of implementing user_access_begin and friends on powerpc, allow_user_access() need to be prepared for user_access_begin() 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. But user_access_end() takes an opaque value returned by user_access_begin(). Make allow_user_access() return the value it writes to current->kuap. This will allow user_access_end() to recalculate the segment range without having to read current->kuap. Signed-off-by: Christophe Leroy --- v3: Replaces the patch "Prepare prevent_user_access() for user_access_end()" --- arch/powerpc/include/asm/book3s/32/kup.h | 15 ++++++++++----- arch/powerpc/include/asm/book3s/64/kup-radix.h | 7 +++++-- arch/powerpc/include/asm/kup.h | 8 ++++++-- arch/powerpc/include/asm/nohash/32/kup-8xx.h | 6 ++++-- 4 files changed, 25 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 3c1798e56b55..128dcbf3a19d 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -102,23 +102,28 @@ static inline void kuap_update_sr(u32 sr, u32 addr, u32 end) isync(); /* Context sync required after mtsrin() */ } -static __always_inline void allow_user_access(void __user *to, const void __user *from, - u32 size, unsigned long dir) +/* Make sure we never return 0. We only use top and bottom 4 bits */ +static __always_inline unsigned long +allow_user_access(void __user *to, const void __user *from, u32 size, unsigned long dir) { u32 addr, end; + unsigned long kuap; BUILD_BUG_ON(!__builtin_constant_p(dir)); if (!(dir & KUAP_W)) - return; + return 0x100; addr = (__force u32)to; if (unlikely(addr >= TASK_SIZE || !size)) - return; + return 0x100; end = min(addr + size, TASK_SIZE); - current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); + kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); + current->thread.kuap = kuap; kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */ + + return kuap; } static __always_inline void prevent_user_access(void __user *to, const void __user *from, diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index f11315306d41..183f0c87017b 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -77,8 +77,9 @@ static inline void set_kuap(unsigned long value) isync(); } -static __always_inline void allow_user_access(void __user *to, const void __user *from, - unsigned long size, unsigned long dir) +static __always_inline unsigned long +allow_user_access(void __user *to, const void __user *from, + unsigned long size, unsigned long dir) { // This is written so we can resolve to a single case at build time BUILD_BUG_ON(!__builtin_constant_p(dir)); @@ -88,6 +89,8 @@ static __always_inline void allow_user_access(void __user *to, const void __user set_kuap(AMR_KUAP_BLOCK_READ); else set_kuap(0); + + return 1; } 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 ff57bfcb88f7..691fec5afd4a 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -45,8 +45,12 @@ static inline void setup_kuep(bool disabled) { } void setup_kuap(bool disabled); #else static inline void setup_kuap(bool disabled) { } -static inline void allow_user_access(void __user *to, const void __user *from, - unsigned long size, unsigned long dir) { } +static inline unsigned long allow_user_access(void __user *to, const void __user *from, + unsigned long size, unsigned long dir) +{ + return 1; +} + static inline void prevent_user_access(void __user *to, const void __user *from, unsigned long size, unsigned long dir) { } static inline bool diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h index 1d70c80366fd..ee673d3c0ab6 100644 --- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -34,10 +34,12 @@ #include -static inline void allow_user_access(void __user *to, const void __user *from, - unsigned long size, unsigned long dir) +static inline unsigned long allow_user_access(void __user *to, const void __user *from, + unsigned long size, unsigned long dir) { mtspr(SPRN_MD_AP, MD_APG_INIT); + + return 1; } static inline void prevent_user_access(void __user *to, const void __user *from,