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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 3F00CC433E6 for ; Mon, 1 Feb 2021 11:29:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E79F264EA7 for ; Mon, 1 Feb 2021 11:29:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229586AbhBAL3f (ORCPT ); Mon, 1 Feb 2021 06:29:35 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:35516 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbhBAL3a (ORCPT ); Mon, 1 Feb 2021 06:29:30 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0UNaSvLm_1612178922; Received: from B-455UMD6M-2027.local(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0UNaSvLm_1612178922) by smtp.aliyun-inc.com(127.0.0.1); Mon, 01 Feb 2021 19:28:43 +0800 Subject: Re: [PATCH v3 1/5] selftests/x86: Simplify the code to get vdso base address in sgx To: Jarkko Sakkinen Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Sean Christopherson , Shuah Khan , x86@kernel.org, linux-sgx@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Jia Zhang References: From: Tianjia Zhang Message-ID: Date: Mon, 1 Feb 2021 19:28:42 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Hi, On 1/26/21 2:12 AM, Jarkko Sakkinen wrote: > What the short summary is saying now, is that this commit would make the > existing code to use vDSO base address. It's already doing that. > > You could instead just "Use getauxval() to simplify the code". > > Also, I'd prefer to properly use upper and lower case letter, e.g. vDSO > instead of vdso. > > Reply-To: > In-Reply-To: <20210124062907.88229-2-tianjia.zhang@linux.alibaba.com> > > On Sun, Jan 24, 2021 at 02:29:03PM +0800, Tianjia Zhang wrote: >> This patch uses the library function `getauxval(AT_SYSINFO_EHDR)` >> instead of the custom function `vdso_get_base_addr` to obtain the > > Use either double or single quotation mark instead of hyphen. > >> base address of vDSO, which will simplify the code implementation. >> >> Signed-off-by: Tianjia Zhang > > This needs to be imperative form, e.g. "Simplify the code implemntation > by using getauxval() instead of a custom function." > >> --- >> tools/testing/selftests/sgx/main.c | 24 ++++-------------------- >> 1 file changed, 4 insertions(+), 20 deletions(-) >> >> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c >> index 724cec700926..365d01dea67b 100644 >> --- a/tools/testing/selftests/sgx/main.c >> +++ b/tools/testing/selftests/sgx/main.c >> @@ -15,6 +15,7 @@ >> #include >> #include >> #include >> +#include >> #include "defines.h" >> #include "main.h" >> #include "../kselftest.h" >> @@ -28,24 +29,6 @@ struct vdso_symtab { >> Elf64_Word *elf_hashtab; >> }; >> >> -static void *vdso_get_base_addr(char *envp[]) >> -{ >> - Elf64_auxv_t *auxv; >> - int i; >> - >> - for (i = 0; envp[i]; i++) >> - ; >> - >> - auxv = (Elf64_auxv_t *)&envp[i + 1]; >> - >> - for (i = 0; auxv[i].a_type != AT_NULL; i++) { >> - if (auxv[i].a_type == AT_SYSINFO_EHDR) >> - return (void *)auxv[i].a_un.a_val; >> - } >> - >> - return NULL; >> -} >> - >> static Elf64_Dyn *vdso_get_dyntab(void *addr) >> { >> Elf64_Ehdr *ehdr = addr; >> @@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r >> return 0; >> } >> >> -int main(int argc, char *argv[], char *envp[]) >> +int main(int argc, char *argv[]) >> { >> struct sgx_enclave_run run; >> struct vdso_symtab symtab; >> @@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[]) >> memset(&run, 0, sizeof(run)); >> run.tcs = encl.encl_base; >> >> - addr = vdso_get_base_addr(envp); >> + /* Get vDSO base address */ >> + addr = (void *)(uintptr_t)getauxval(AT_SYSINFO_EHDR); > > You could just case the result the result directly to void *. > >> if (!addr) >> goto err; >> >> -- >> 2.19.1.3.ge56e4f7 >> >> > > /Jarkko > Thanks for your suggestions, I will fix it in the v4 patchset. Best regards, Tianjia