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 05890CDB465 for ; Sat, 14 Oct 2023 23:20:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231893AbjJNXUt (ORCPT ); Sat, 14 Oct 2023 19:20:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229733AbjJNXUs (ORCPT ); Sat, 14 Oct 2023 19:20:48 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F12C3A9; Sat, 14 Oct 2023 16:20:46 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FFDDC433C8; Sat, 14 Oct 2023 23:20:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697325646; bh=pZByRqicRE3aNH8i7QtO2qzFZjBI0dEQxI30C4vTcFM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JsO3biSddsSf/3of9SNqflvn9NwMYaIVb1GWLx8DyxtCghQnqIQRp9oFJvz8jsn2C qXPQdapZoCvEHn+RzeltXOBRvdK0WhgFTaxCE22N/oCBRjiVGhMmTmEtZxFmTaQnym 5hBZgjrjjf8ZWY78xHwQIj+bB5x8f681olw5pmoFAxMhBm5eXltn3Ti8hYhiBbm5uk S3fMNdpect2CNOtkiXy3oxoTL12BU98kjPt/R5RlK8fahNTF9FYy3SlBRfZPcMCEJ6 b6Ouf6gBvNqX8HtRdwE7A9ChjvnVwGQKuJHHdP7jZzOQmLb+4Dd5+rrnW8QiKmozuB G8lVJsgUF0qcw== Date: Sun, 15 Oct 2023 01:20:42 +0200 From: Alejandro Colomar To: Guo Ren Cc: linux-man , linux-kernel , linux-csky@vger.kernel.org, Arnd Bergmann Subject: Re: set_thread_area.2: csky architecture undocumented Message-ID: References: <014e670b-2a11-3deb-4e7e-bfe9defd8597@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="+7sKm7wLEzKNfm8V" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org --+7sKm7wLEzKNfm8V Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Sun, 15 Oct 2023 01:20:42 +0200 From: Alejandro Colomar To: Guo Ren Cc: linux-man , linux-kernel , linux-csky@vger.kernel.org, Arnd Bergmann Subject: Re: set_thread_area.2: csky architecture undocumented Hi Guo, On Tue, Nov 24, 2020 at 08:07:07PM +0800, Guo Ren wrote: Huh, 3 years already! I've had this in my head for all this time; just didn't find the energy to act on it. > Thx Michael & Alejandro, >=20 > Yes, the man page has no csky's. I've applied a patch to add initial documentation for it: >=20 > C-SKY have abiv1 and abiv2 > For abiv1: There is no register for tls saving, We use trap 3 to got > tls and use set_thread_area to init ti->tp_value. > For abiv2: The r31 is the tls register. We could directly read r31 to > got r31 and use set_thread_area to init reg->tls value. >=20 > In glibc: > # ifdef __CSKYABIV2__ > /* Define r31 as thread pointer register. */ > # define READ_THREAD_POINTER() \ > mov r0, r31; > # else > # define READ_THREAD_POINTER() \ > trap 3; > # endif >=20 > /* Code to initially initialize the thread pointer. This might need > special attention since 'errno' is not yet available and if the > operation can cause a failure 'errno' must not be touched. */ > # define TLS_INIT_TP(tcbp) \ > ({ INTERNAL_SYSCALL_DECL (err); \ > long result_var; \ > result_var =3D INTERNAL_SYSCALL (set_thread_area, err, 1, = \ > (char *) (tcbp) + TLS_TCB_OFFSET); \ > INTERNAL_SYSCALL_ERROR_P (result_var, err) \ > ? "unknown error" : NULL; }) >=20 > In kernel: > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > { > struct thread_info *ti =3D task_thread_info(current); > struct pt_regs *reg =3D current_pt_regs(); >=20 > reg->tls =3D addr; > ti->tp_value =3D addr; >=20 > return 0; > } >=20 > Any comments are welcome :) I'm sorry, but I have little understanding of this syscall, and that shounds like gibberish to me :) Feel free to send a patch to improve the documentation for csky. Cheers, Alex >=20 >=20 > On Tue, Nov 24, 2020 at 5:51 PM Michael Kerrisk (man-pages) > wrote: > > > > Hi Alex, > > > > On 11/23/20 10:31 PM, Alejandro Colomar (man-pages) wrote: > > > Hi Michael, > > > > > > SYNOPSIS > > > #include > > > > > > #if defined __i386__ || defined __x86_64__ > > > # include > > > > > > int get_thread_area(struct user_desc *u_info); > > > int set_thread_area(struct user_desc *u_info); > > > > > > #elif defined __m68k__ > > > > > > int get_thread_area(void); > > > int set_thread_area(unsigned long tp); > > > > > > #elif defined __mips__ > > > > > > int set_thread_area(unsigned long addr); > > > > > > #endif > > > > > > Note: There are no glibc wrappers for these system calls; see > > > NOTES. > > > > > > > > > $ grep -rn 'SYSCALL_DEFINE.*et_thread_area' > > > arch/csky/kernel/syscall.c:6: > > > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > > > arch/mips/kernel/syscall.c:86: > > > SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) > > > arch/x86/kernel/tls.c:191: > > > SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, u_info) > > > arch/x86/kernel/tls.c:243: > > > SYSCALL_DEFINE1(get_thread_area, struct user_desc __user *, u_info) > > > arch/x86/um/tls_32.c:277: > > > SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, user_desc) > > > arch/x86/um/tls_32.c:325: > > > SYSCALL_DEFINE1(get_thread_area, struct user_desc __user *, user_desc) > > > > > > > > > See kernel commit 4859bfca11c7d63d55175bcd85a75d6cee4b7184 > > > > > > > > > I'd change > > > - #elif defined __mips__ > > > + #elif defined(__mips__ || __csky__) > > > > > > and then change the rest of the text to add csky when appropriate. > > > Am I correct? > > > > AFAICT, you are correct. I think the reason that csky is missing is > > that the architecture was added after this manual pages was added. > > > > Thanks, > > > > Michael > > > > > > -- > > Michael Kerrisk > > Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ > > Linux/UNIX System Programming Training: http://man7.org/training/ >=20 >=20 >=20 > -- > Best Regards > Guo Ren >=20 > ML: https://lore.kernel.org/linux-csky/ --=20 --+7sKm7wLEzKNfm8V Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmUrIkoACgkQnowa+77/ 2zJBLQ//XczzypNTi/1rlE2DDav7YKOaYkSEV4zNIYOD7QRlFeu5bZloPNIpMm2i dvwoKgQv+Jkex+diXoab4qDLD7oj8H+Ykrg4yEshEOP0f4BULBG6sV2/FieDIuoj fWauz5kls3qTCUNa3omyFAa7IbbQ01Lrn89JzMBxw8mo7MSMYv/WObWsc/BsPEAU gVPdVjCNwKJHajBIPAkSSnMBl83fqfGEsahdC1BrGe6NiDgAnCptcIOnGv8Qkgsn ElV1vwLGN3OESajN3fJz5iWhBB6xkgoCI1E9iYCYfj44AZDzpfnFD9M9yQHuEOsg TkEWkY5HdsJ/PhIcWn9Renwl/0rFvpV+2VYOY4Zm0P967uTP3Tbi+6fOy2g+VHgE 6Cn7IxBoQ4gdH/NuLHfgbNPu5ZfS7vAKWTB7HRAu7tmLHWIUy50nZ6Q7zRCvgy9T 4SCkFgPJsUB0IVhxCrgqgzlVB+ihk/Cr434z6GIZjZUE0bxTzHYtbMgTs44N2HpQ 0l0lpaA8RDEwUIDXLZhzk62EjnYZcBGNeziOY4gYahru2uTOMg3K6qYBfKMzdYva 79KWKO0VeVXIQN2zuVwi6mQa5biUQGDjxk3io/lgsIU64PN1FczV9EYoxSWQnoM4 +44LIov8C3BiswxLN+XVJE1ZWPq7Nk6CBnoNy1ofMdPdr9jbHSg= =QgYa -----END PGP SIGNATURE----- --+7sKm7wLEzKNfm8V--