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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 0A4F8C433DB for ; Fri, 12 Mar 2021 13:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C149264FB8 for ; Fri, 12 Mar 2021 13:25:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230491AbhCLNZQ (ORCPT ); Fri, 12 Mar 2021 08:25:16 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:54682 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229568AbhCLNZO (ORCPT ); Fri, 12 Mar 2021 08:25:14 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DxmlD0Dylz9ttBh; Fri, 12 Mar 2021 14:25:12 +0100 (CET) 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 3005F1ETpgzu; Fri, 12 Mar 2021 14:25:11 +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 4DxmlC6Nkjz9ttBY; Fri, 12 Mar 2021 14:25:11 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 598788B815; Fri, 12 Mar 2021 14:25:12 +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 a_PaZruFI7yH; Fri, 12 Mar 2021 14:25:12 +0100 (CET) Received: from po16121vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id EEEA38B812; Fri, 12 Mar 2021 14:25:11 +0100 (CET) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id BB23B675BA; Fri, 12 Mar 2021 13:25:11 +0000 (UTC) Message-Id: In-Reply-To: <0ad4629c2d222019e82fcdfccc70d372beb4adf9.1615398265.git.christophe.leroy@csgroup.eu> References: <0ad4629c2d222019e82fcdfccc70d372beb4adf9.1615398265.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Subject: [PATCH v3 03/15] powerpc/align: Convert emulate_spe() to user_access_begin To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Daniel Axtens Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Fri, 12 Mar 2021 13:25:11 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch converts emulate_spe() to using user_access_begin logic. Since commit 662bbcb2747c ("mm, sched: Allow uaccess in atomic with pagefault_disable()"), might_fault() doesn't fire when called from sections where pagefaults are disabled, which must be the case when using _inatomic variants of __get_user and __put_user. So the might_fault() in user_access_begin() is not a problem. There was a verification of user_mode() together with the access_ok(), but there is a second verification of user_mode() just after, that leads to immediate return. The access_ok() is now part of the user_access_begin which is called after that other user_mode() verification, so no need to check user_mode() again. Signed-off-by: Christophe Leroy Reviewed-by: Daniel Axtens --- v3: - Changed the second user_read_access_begin() to user_write_access_begin() - Reworded explaination about the user_mode() with access_ok() in the commit message --- arch/powerpc/kernel/align.c | 61 ++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 28 deletions(-) diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c index c7797eb958c7..f362c99213be 100644 --- a/arch/powerpc/kernel/align.c +++ b/arch/powerpc/kernel/align.c @@ -107,7 +107,6 @@ static struct aligninfo spe_aligninfo[32] = { static int emulate_spe(struct pt_regs *regs, unsigned int reg, struct ppc_inst ppc_instr) { - int ret; union { u64 ll; u32 w[2]; @@ -127,11 +126,6 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, nb = spe_aligninfo[instr].len; flags = spe_aligninfo[instr].flags; - /* Verify the address of the operand */ - if (unlikely(user_mode(regs) && - !access_ok(addr, nb))) - return -EFAULT; - /* userland only */ if (unlikely(!user_mode(regs))) return 0; @@ -169,26 +163,27 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, } } else { temp.ll = data.ll = 0; - ret = 0; p = addr; + if (!user_read_access_begin(addr, nb)) + return -EFAULT; + switch (nb) { case 8: - ret |= __get_user_inatomic(temp.v[0], p++); - ret |= __get_user_inatomic(temp.v[1], p++); - ret |= __get_user_inatomic(temp.v[2], p++); - ret |= __get_user_inatomic(temp.v[3], p++); + unsafe_get_user(temp.v[0], p++, Efault_read); + unsafe_get_user(temp.v[1], p++, Efault_read); + unsafe_get_user(temp.v[2], p++, Efault_read); + unsafe_get_user(temp.v[3], p++, Efault_read); fallthrough; case 4: - ret |= __get_user_inatomic(temp.v[4], p++); - ret |= __get_user_inatomic(temp.v[5], p++); + unsafe_get_user(temp.v[4], p++, Efault_read); + unsafe_get_user(temp.v[5], p++, Efault_read); fallthrough; case 2: - ret |= __get_user_inatomic(temp.v[6], p++); - ret |= __get_user_inatomic(temp.v[7], p++); - if (unlikely(ret)) - return -EFAULT; + unsafe_get_user(temp.v[6], p++, Efault_read); + unsafe_get_user(temp.v[7], p++, Efault_read); } + user_read_access_end(); switch (instr) { case EVLDD: @@ -255,31 +250,41 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg, /* Store result to memory or update registers */ if (flags & ST) { - ret = 0; p = addr; + + if (!user_write_access_begin(addr, nb)) + return -EFAULT; + switch (nb) { case 8: - ret |= __put_user_inatomic(data.v[0], p++); - ret |= __put_user_inatomic(data.v[1], p++); - ret |= __put_user_inatomic(data.v[2], p++); - ret |= __put_user_inatomic(data.v[3], p++); + unsafe_put_user(data.v[0], p++, Efault_write); + unsafe_put_user(data.v[1], p++, Efault_write); + unsafe_put_user(data.v[2], p++, Efault_write); + unsafe_put_user(data.v[3], p++, Efault_write); fallthrough; case 4: - ret |= __put_user_inatomic(data.v[4], p++); - ret |= __put_user_inatomic(data.v[5], p++); + unsafe_put_user(data.v[4], p++, Efault_write); + unsafe_put_user(data.v[5], p++, Efault_write); fallthrough; case 2: - ret |= __put_user_inatomic(data.v[6], p++); - ret |= __put_user_inatomic(data.v[7], p++); + unsafe_put_user(data.v[6], p++, Efault_write); + unsafe_put_user(data.v[7], p++, Efault_write); } - if (unlikely(ret)) - return -EFAULT; + user_write_access_end(); } else { *evr = data.w[0]; regs->gpr[reg] = data.w[1]; } return 1; + +Efault_read: + user_read_access_end(); + return -EFAULT; + +Efault_write: + user_write_access_end(); + return -EFAULT; } #endif /* CONFIG_SPE */ -- 2.25.0