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=-6.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 A0751C433E0 for ; Fri, 26 Jun 2020 07:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 739002076E for ; Fri, 26 Jun 2020 07:26:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ZNBlEuV7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728111AbgFZH0i (ORCPT ); Fri, 26 Jun 2020 03:26:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727872AbgFZH0h (ORCPT ); Fri, 26 Jun 2020 03:26:37 -0400 Received: from mail-lf1-x141.google.com (mail-lf1-x141.google.com [IPv6:2a00:1450:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50654C08C5DB for ; Fri, 26 Jun 2020 00:26:37 -0700 (PDT) Received: by mail-lf1-x141.google.com with SMTP id c21so4601884lfb.3 for ; Fri, 26 Jun 2020 00:26:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=cw7fszpLiMfrIe/x4mrTm0zt4AL0ex45ZDoUuui7OOM=; b=ZNBlEuV7nuAwi/3xINotpkZFYoSyoduflbwP1WVpiojIx56BqAK7kAB9tJK6o/fSEC kbJfb9lc10mlxKYEK6VPvYNCqZca2+QVWuRjoUzKsHF+AjulUmncAkiX547o+rNQjwpV DjUN9kW/889p9CxCnaX7XjcwfTjtXzhhfaZuEHnbdkGA058NAM/YpNRc2lgnJiggajQj rJUBCd4BDJHmOJ0uxMEmRRktScwNi58yVxHF35EezzGlrAFWH03pdmx5wHrYCm2FK8eG xF54fddRx3qHIypr4FCCJ13OZ+t3ROCgWLBaWYTrfOtgRPP3oexWKBaRZ7k7DO1Dy7YC eNtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=cw7fszpLiMfrIe/x4mrTm0zt4AL0ex45ZDoUuui7OOM=; b=fBpjpihy1mjLBgdg75a0//BuCzH3v6uIEDL9aezSEDPjBHxzHEl0DJUbKGmvTFqWMK bEkxpdTxiIxuJ/b2HvUffq+PEZ6AWk5KCLgrKs94xnew0TUoz3gOp8luk7SpB4wYNVjS sQhEUFxvy7OYnxywLyYj7OWeQku1WxxwnanMp2xtbQrksiE17MtyJxnVLcdf3xQLE0DI AyJjPsmXGYNMs4Z8L4yzIgII6D4ylCWLvZJdfhZtZ6926y7GdYhKIWpt/Qq66XfKXbsv qq6ek+STZroSbNy1MrwMXRLKzv/v+yJSAHD2u/txNXVxtKsCmkx8P5vS8tJhMag8EerY 4bXQ== X-Gm-Message-State: AOAM5311elebVydMe/nM6ocWlztF3ikEXaqPbQpP0ODzrGlEA2vxWkxN 2ypzmoBoDOBVfXc7Fz9hLtnERtsUNDIHRcGi8d0dIg== X-Google-Smtp-Source: ABdhPJwvCjTPMG3DGY417CWhy1Vn5ylVbzduY+Geu6YJsJsNdoK9hd2Lmls7tX2lk0jNLu/BbDnRv8U9BuFhqvHbPZ4= X-Received: by 2002:ac2:5467:: with SMTP id e7mr1058410lfn.122.1593156395726; Fri, 26 Jun 2020 00:26:35 -0700 (PDT) MIME-Version: 1.0 References: <20200604175851.758-1-maxim.uvarov@linaro.org> <20200604175851.758-2-maxim.uvarov@linaro.org> <1592507935.15159.5.camel@HansenPartnership.com> <1592578844.4369.5.camel@HansenPartnership.com> <1593012069.28403.11.camel@HansenPartnership.com> <1593127902.13253.11.camel@HansenPartnership.com> In-Reply-To: From: Sumit Garg Date: Fri, 26 Jun 2020 12:56:24 +0530 Message-ID: Subject: Re: [Tee-dev] [PATCHv8 1/3] optee: use uuid for sysfs driver entry To: James Bottomley Cc: Jerome Forissier , Maxim Uvarov , Greg Kroah-Hartman , Linux Kernel Mailing List , Jarkko Sakkinen , Arnd Bergmann , "tee-dev @ lists . linaro . org" , Jason Gunthorpe , linux-integrity@vger.kernel.org, peterhuewe@gmx.de Content-Type: text/plain; charset="UTF-8" Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Fri, 26 Jun 2020 at 10:40, Sumit Garg wrote: > > On Fri, 26 Jun 2020 at 05:01, James Bottomley > wrote: > > > > On Thu, 2020-06-25 at 19:54 +0530, Sumit Garg wrote: > > > On Wed, 24 Jun 2020 at 20:51, James Bottomley > > > wrote: > > > > > > > > On Wed, 2020-06-24 at 16:17 +0530, Sumit Garg wrote: > > > > > Apologies for delay in my reply as I was busy with some other > > > > > stuff. > > > > > > > > > > On Fri, 19 Jun 2020 at 20:30, James Bottomley > > > > > wrote: > > > > > > > > [...] > > > > > > it's about consistency with what the kernel types mean. When > > > > > > some checker detects your using little endian operations on a > > > > > > big endian structure (like in the prink for instance) they're > > > > > > going to keep emailing you about it. > > > > > > > > > > As mentioned above, using different terminology is meant to cause > > > > > more confusion than just difference in endianness which is > > > > > manageable inside TEE. > > > > > > > > > > And I think it's safe to say that the kernel implements UUID in > > > > > big endian format and thus uses %pUb whereas OP-TEE implements > > > > > UUID in little endian format and thus uses %pUl. > > > > > > > > So what I think you're saying is that if we still had uuid_be and > > > > uuid_le you'd use uuid_le, because that's exactly the structure > > > > described in the docs. But because we renamed > > > > > > > > uuid_be -> uuid_t > > > > uuid_le -> guid_t > > > > > > > > You can't use guid_t as a kernel type because it has the wrong > > > > name? > > > > > > Isn't the rename commit description [1] pretty clear about which is > > > the true UUID type from Linux point of view? > > > > I don't think the kernel code takes a position on eternal verity, just > > on logical or arithmetic truth. We just have to deal with both LE and > > BE UUIDs so we have appropriate types for them and the LE type is now > > named guid_t. They're both equally correct to use provided the use > > case matches the designed one. So does the name really matter? > > Yes it does. I guess I have provided enough reasoning for that. Also, > the rename commit itself illustrates its importance and clarifies the > use case for which they are meant to be used. > > > If we > > did > > > > #define uuid_le_t guid_t > > > > would you be happy? (not that the kernel cares about karmic emotional > > states either ...) > > It's not about me being happy but more about confusion and > inconsistency it will bring. > > IMO, either kernel should be opinionated about UUID endianness like > currently it is: > > uuid_t and its corresponding helpers (eg. UUID_INIT) follows BE format. > > or support both endianness for UUID (no common type: uuid_t) like we > had earlier prior to rename commit: > > uuid_be_t and its corresponding helpers (eg. UUID_BE_INIT) follow BE format. > uuid_le_t and its corresponding helpers (eg. UUID_LE_INIT) follow LE format. > > But even if we consider later case as well, I am still not sure if we > can switch to uuid_le_t as it's been part of TEE core ABI > (open_session) where UUID is passed in BE format (see LE to BE > conversion in TEE client [1] and vice-versa in OP-TEE OS [2]) and > won't be a backwards compatible change. > > [1] https://github.com/OP-TEE/optee_client/blob/master/libteec/src/tee_client_api.c#L595 > [2] https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/kernel/ree_fs_ta.c#L92 Sorry, the second reference is incorrect, correct one is: [2] https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/tee/entry_std.c#L279 -Sumit > > -Sumit > > > > > James > >