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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8D72C43334 for ; Sat, 18 Jun 2022 08:42:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 403A46B0071; Sat, 18 Jun 2022 04:42:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3B3016B0072; Sat, 18 Jun 2022 04:42:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 27B5D6B0073; Sat, 18 Jun 2022 04:42:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 182906B0071 for ; Sat, 18 Jun 2022 04:42:13 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id E4DB7354FE for ; Sat, 18 Jun 2022 08:42:12 +0000 (UTC) X-FDA: 79590714504.26.0010CAB Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf05.hostedemail.com (Postfix) with ESMTP id 26FA510008E for ; Sat, 18 Jun 2022 08:42:12 +0000 (UTC) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4LQ8Wd01gMzYXPC; Sat, 18 Jun 2022 16:41:01 +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 16:42:09 +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 16:42:07 +0800 Message-ID: <0da734f3-5743-3df3-3f90-d92e5bd585ce@huawei.com> Date: Sat, 18 Jun 2022 16:42:06 +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 From: Tong Tiangen 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> <4371a7c9-8766-9fee-2558-e6f43f06ad19@huawei.com> In-Reply-To: <4371a7c9-8766-9fee-2558-e6f43f06ad19@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf05.hostedemail.com: domain of tongtiangen@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=tongtiangen@huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655541732; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ne9tLmbihEisK82+C7TEPN2F/bwWf30Hc6Mhk3LSptg=; b=hFhpONrwZC3K1v1fIpGG2gF1+sTBlEtz7yF9HGkIOxWax/YS2bIdjgiCxPzPFy+l0q9Yh4 wcz4gBXDl5Q6wnlCadmztnnszcSDTp0ChyygqA7b0l5C7tKVTls19DINl5FeGjt64o9bwU COSTH+Dr/gLgXZKs8WP8Olg/OrE6KQg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655541732; a=rsa-sha256; cv=none; b=JG3nYoV4HYVCjl6t7IziFjqJw8bhsJnmP61/fuxKSdyHuKSpdbe2m6X0V5rg5sV5VSsMVO atXQNuLn+iBr4VK0cgAlSQTVl3cQPA3zp7yOM4S3J9Rc/nB8xQ/FZH1a5BCkaP6QROXdJM avvOoPolaPTZnwVRj7+0UbTrbgVKmWg= X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 26FA510008E X-Rspam-User: Authentication-Results: imf05.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf05.hostedemail.com: domain of tongtiangen@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=tongtiangen@huawei.com X-Stat-Signature: fmncn9y66xu64o6qsqoqk9fk85oc9ye3 X-HE-Tag: 1655541732-116784 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: 在 2022/6/18 11:26, Tong Tiangen 写道: > > > 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. I tried to using data filelds as with C version, but here assembly code we can not using operator such as << and |, if we use lsl and orr instructions, the gpr will be occupied. So how about using 0x3ff directly here? it means err register and zero register both set to x31. 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 >>> >> . > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel