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 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 7C36BC4338F for ; Mon, 23 Aug 2021 15:36:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CA2B61262 for ; Mon, 23 Aug 2021 15:36:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231761AbhHWPgs (ORCPT ); Mon, 23 Aug 2021 11:36:48 -0400 Received: from pegase2.c-s.fr ([93.17.235.10]:60915 "EHLO pegase2.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231680AbhHWPgn (ORCPT ); Mon, 23 Aug 2021 11:36:43 -0400 Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4GtbtM3Y7gz9sWt; Mon, 23 Aug 2021 17:35:55 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jHYq65ia1aAv; Mon, 23 Aug 2021 17:35:55 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4GtbtL4yHqz9sWm; Mon, 23 Aug 2021 17:35:54 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8F62E8B7AF; Mon, 23 Aug 2021 17:35:54 +0200 (CEST) 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 HlAq6WByRKMp; Mon, 23 Aug 2021 17:35:54 +0200 (CEST) Received: from po18078vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.100]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 6CA438B7AD; Mon, 23 Aug 2021 17:35:54 +0200 (CEST) Received: by po18078vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 654E26BC7C; Mon, 23 Aug 2021 15:35:54 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH v2 4/5] powerpc/uaccess: Add unsafe_clear_user() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Mon, 23 Aug 2021 15:35:54 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement unsafe_clear_user() for powerpc. It's a copy/paste of unsafe_copy_to_user() with value 0 as source. It may be improved in a later patch by using 'dcbz' instruction to zeroize full cache lines at once. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/uaccess.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 22c79ab40006..962b675485ff 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -467,6 +467,26 @@ do { \ unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \ } while (0) +#define unsafe_clear_user(d, l, e) \ +do { \ + u8 __user *_dst = (u8 __user *)(d); \ + size_t _len = (l); \ + int _i; \ + \ + for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \ + unsafe_put_user(0, (u64 __user *)(_dst + _i), e); \ + if (_len & 4) { \ + unsafe_put_user(0, (u32 __user *)(_dst + _i), e); \ + _i += 4; \ + } \ + if (_len & 2) { \ + unsafe_put_user(0, (u16 __user *)(_dst + _i), e); \ + _i += 2; \ + } \ + if (_len & 1) \ + unsafe_put_user(0, (u8 __user *)(_dst + _i), e); \ +} while (0) + #define HAVE_GET_KERNEL_NOFAULT #define __get_kernel_nofault(dst, src, type, err_label) \ -- 2.25.0