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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 991F8C433EF for ; Sat, 18 Jun 2022 03:26:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383784AbiFRD0j (ORCPT ); Fri, 17 Jun 2022 23:26:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235542AbiFRD0g (ORCPT ); Fri, 17 Jun 2022 23:26:36 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D5B237032 for ; Fri, 17 Jun 2022 20:26:35 -0700 (PDT) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LQ1Sw4DW3zBrnv; Sat, 18 Jun 2022 11:23:12 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 18 Jun 2022 11:26:33 +0800 Received: from [10.174.179.234] (10.174.179.234) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 18 Jun 2022 11:26:31 +0800 Message-ID: <4371a7c9-8766-9fee-2558-e6f43f06ad19@huawei.com> Date: Sat, 18 Jun 2022 11:26:30 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH -next v5 2/8] arm64: extable: make uaaccess helper use extable type EX_TYPE_UACCESS_ERR_ZERO To: Mark Rutland CC: James Morse , Andrew Morton , Thomas Gleixner , "Ingo Molnar" , Borislav Petkov , Robin Murphy , Dave Hansen , "Catalin Marinas" , Will Deacon , "Alexander Viro" , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , , "H . Peter Anvin" , , , , , Kefeng Wang , Xie XiuQi , Guohanjun References: <20220528065056.1034168-1-tongtiangen@huawei.com> <20220528065056.1034168-3-tongtiangen@huawei.com> From: Tong Tiangen In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/6/17 16:24, Mark Rutland 写道: > On Sat, May 28, 2022 at 06:50:50AM +0000, Tong Tiangen wrote: >> Currnetly, the extable type used by __arch_copy_from/to_user() is >> EX_TYPE_FIXUP. In fact, It is more clearly to use meaningful >> EX_TYPE_UACCESS_*. >> >> Suggested-by: Mark Rutland >> Signed-off-by: Tong Tiangen >> --- >> arch/arm64/include/asm/asm-extable.h | 8 ++++++++ >> arch/arm64/include/asm/asm-uaccess.h | 12 ++++++------ >> 2 files changed, 14 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h >> index 56ebe183e78b..9c94ac1f082c 100644 >> --- a/arch/arm64/include/asm/asm-extable.h >> +++ b/arch/arm64/include/asm/asm-extable.h >> @@ -28,6 +28,14 @@ >> __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) >> .endm >> >> +/* >> + * Create an exception table entry for uaccess `insn`, which will branch to `fixup` >> + * when an unhandled fault is taken. >> + * ex->data = ~0 means both reg_err and reg_zero is set to wzr(x31). >> + */ >> + .macro _asm_extable_uaccess, insn, fixup >> + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_ERR_ZERO, ~0) >> + .endm > > I'm not too keen on using `~0` here, since that also sets other bits in the > data field, and its somewhat opaque. > > How painful is it to generate the data fields as with the C version of this > macro, so that we can pass in wzr explciitly for the two sub-fields? > > Other than that, this looks good to me. > > Thanks, > Mark. ok, will fix next version. Thanks, Tong. > >> /* >> * Create an exception table entry for `insn` if `fixup` is provided. Otherwise >> * do nothing. >> diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h >> index 0557af834e03..75b211c98dea 100644 >> --- a/arch/arm64/include/asm/asm-uaccess.h >> +++ b/arch/arm64/include/asm/asm-uaccess.h >> @@ -61,7 +61,7 @@ alternative_else_nop_endif >> >> #define USER(l, x...) \ >> 9999: x; \ >> - _asm_extable 9999b, l >> + _asm_extable_uaccess 9999b, l >> >> /* >> * Generate the assembly for LDTR/STTR with exception table entries. >> @@ -73,8 +73,8 @@ alternative_else_nop_endif >> 8889: ldtr \reg2, [\addr, #8]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> - _asm_extable 8889b,\l; >> + _asm_extable_uaccess 8888b, \l; >> + _asm_extable_uaccess 8889b, \l; >> .endm >> >> .macro user_stp l, reg1, reg2, addr, post_inc >> @@ -82,14 +82,14 @@ alternative_else_nop_endif >> 8889: sttr \reg2, [\addr, #8]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> - _asm_extable 8889b,\l; >> + _asm_extable_uaccess 8888b,\l; >> + _asm_extable_uaccess 8889b,\l; >> .endm >> >> .macro user_ldst l, inst, reg, addr, post_inc >> 8888: \inst \reg, [\addr]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> + _asm_extable_uaccess 8888b, \l; >> .endm >> #endif >> -- >> 2.25.1 >> > .