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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 21AA6C0650E for ; Thu, 4 Jul 2019 09:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9E2E218A3 for ; Thu, 4 Jul 2019 09:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727291AbfGDJTd (ORCPT ); Thu, 4 Jul 2019 05:19:33 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:33614 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727147AbfGDJTa (ORCPT ); Thu, 4 Jul 2019 05:19:30 -0400 Received: by mail-qt1-f194.google.com with SMTP id h24so7378782qto.0 for ; Thu, 04 Jul 2019 02:19:30 -0700 (PDT) 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=UU1LRzgJ9KtlIamPG1rpTOdBbiRt377kXD3IRu4KTEc=; b=WgiZHTN9qZ6nFhuCUpG2LVjkyW3WX5VDZn4TPjBad3pSSXROgjqBp1RCASoCNesZKM uKmDqEW+/vZyuouz5O1CbpKmDHpq7hwd6G9I6i2VnFgXheNpwr9VuM67k6yFhqS0Nxda t2kkB3GVbtz+tlKxd6aKOBM6sI/DHcRznSwyXPHaPQNeW+V20ZId5LiEchdeyP4HD4G1 InWh36VgRRFtPKRVPfxoBRTv+5IP97KvQb05+UqZAbKjaFQNWzavpl17tDkOP69sL4N+ bvPgwVWmrywkbqOZJytsNfl27XaLTd+7vrR23siorcjR2VjOb8K5CZfzRiBxsakmIHY7 y7UA== X-Gm-Message-State: APjAAAWwpLPfQQ9zlqsA41v6erOc3/EE5CD3kwd9KJJf2ylWTgpDDKxg suJPIJdFEdA4dl8tboiStjZYPys6Dx/MghUj62wk8IhE34o= X-Google-Smtp-Source: APXvYqz9HnBRmgYL+EgQde6QoC+3TNiwekg2y+kqVusM0V3Keg/hNYgvdDkMLVnEv4+p3P8DAILsb6JwSzdx30DpREE= X-Received: by 2002:aed:3363:: with SMTP id u90mr2705494qtd.7.1562231969777; Thu, 04 Jul 2019 02:19:29 -0700 (PDT) MIME-Version: 1.0 References: <20190703005202.7578-1-alistair.francis@wdc.com> In-Reply-To: From: Arnd Bergmann Date: Thu, 4 Jul 2019 11:19:13 +0200 Message-ID: Subject: Re: [PATCH RESEND 0/2] RISC-V: Handle the siginfo_t offset problem To: Andreas Schwab Cc: Alistair Francis , Alistair Francis , linux-riscv@lists.infradead.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 4, 2019 at 9:20 AM Andreas Schwab wrote: > > On Jul 03 2019, Alistair Francis wrote: > > > On Wed, Jul 3, 2019 at 12:08 AM Andreas Schwab wrote: > >> > >> On Jul 02 2019, Alistair Francis wrote: > >> > >> > In the RISC-V 32-bit glibc port [1] the siginfo_t struct in the kernel > >> > doesn't line up with the struct in glibc. In glibc world the _sifields > >> > union is 8 byte alligned (although I can't figure out why) > >> > >> Try ptype/o in gdb. > > > > That's a useful tip, I'll be sure to use that next time. > > It was a serious note. If the structs don't line up then there is a > mismatch in types that cannot be solved by adding spurious padding. You > need to fix the types instead. Would it be an option to align all the basic typedefs (off_t, time_t, clock_t, ...) between glibc and kernel then, and just use the existing sysdeps/unix/sysv/linux/generic/bits/typesizes.h after all to avoid surprises like this? As of v2 the functional difference is -#define __INO_T_TYPE __ULONGWORD_TYPE +#define __INO_T_TYPE __UQUAD_TYPE #define __INO64_T_TYPE __UQUAD_TYPE #define __MODE_T_TYPE __U32_TYPE -#define __NLINK_T_TYPE __U32_TYPE -#define __OFF_T_TYPE __SLONGWORD_TYPE +#define __NLINK_T_TYPE __UQUAD_TYPE +#define __OFF_T_TYPE __SQUAD_TYPE #define __OFF64_T_TYPE __SQUAD_TYPE -#define __RLIM_T_TYPE __ULONGWORD_TYPE +#define __RLIM_T_TYPE __UQUAD_TYPE #define __RLIM64_T_TYPE __UQUAD_TYPE -#define __BLKCNT_T_TYPE __SLONGWORD_TYPE +#define __BLKCNT_T_TYPE __SQUAD_TYPE #define __BLKCNT64_T_TYPE __SQUAD_TYPE -#define __FSBLKCNT_T_TYPE __ULONGWORD_TYPE +#define __FSBLKCNT_T_TYPE __UQUAD_TYPE #define __FSBLKCNT64_T_TYPE __UQUAD_TYPE -#define __FSFILCNT_T_TYPE __ULONGWORD_TYPE +#define __FSFILCNT_T_TYPE __UQUAD_TYPE #define __FSFILCNT64_T_TYPE __UQUAD_TYPE -#define __FSWORD_T_TYPE __SWORD_TYPE +#define __FSWORD_T_TYPE __SQUAD_TYPE -#define __CLOCK_T_TYPE __SLONGWORD_TYPE -#define __TIME_T_TYPE __SLONGWORD_TYPE +#define __CLOCK_T_TYPE __SQUAD_TYPE +#define __TIME_T_TYPE __SQUAD_TYPE #define __USECONDS_T_TYPE __U32_TYPE -#define __SUSECONDS_T_TYPE __SLONGWORD_TYPE +#define __SUSECONDS_T_TYPE __SQUAD_TYPE -#define __BLKSIZE_T_TYPE __S32_TYPE +#define __BLKSIZE_T_TYPE __SQUAD_TYPE #define __FSID_T_TYPE struct { int __val[2]; } #define __SSIZE_T_TYPE __SWORD_TYPE -#define __SYSCALL_SLONG_TYPE __SLONGWORD_TYPE -#define __SYSCALL_ULONG_TYPE __ULONGWORD_TYPE -#define __CPU_MASK_TYPE __ULONGWORD_TYPE +#define __SYSCALL_SLONG_TYPE __SQUAD_TYPE +#define __SYSCALL_ULONG_TYPE __UQUAD_TYPE +#define __CPU_MASK_TYPE __UQUAD_TYPE -#ifdef __LP64__ # define __RLIM_T_MATCHES_RLIM64_T 1 -#else -# define __RLIM_T_MATCHES_RLIM64_T 0 -#endif +#define __ASSUME_TIME64_SYSCALLS 1 +#define __ASSUME_RLIM64_SYSCALLS 1 Since the sysdeps/unix/sysv/linux/generic/bits/typesizes.h definitions generally match the kernel, anything diverging from that has the potential of breaking it, so the difference should probably be kept to the absolute minimum. I think these ones are wrong and will cause bugs similar to the clock_t issue if they are used with kernel interfaces: __NLINK_T_TYPE, __FSWORD_T_TYPE, __CLOCK_T_TYPE, __BLKSIZE_T_TYPE, __SYSCALL_ULONG_TYPE, __SYSCALL_SLONG_TYPE, __CPU_MASK_TYPE These are fine as long as they are only used in user space and to wrap kernel syscalls, but I think most of them can end up being passed to the kernel, so it seems safer not to have rv32 diverge without a good reason. The remaining ones (__INO_T_TYPE, __OFF_T_TYPE, __BLKCNT_T_TYPE, __FSBLKCNT_T_TYPE, __FSFILCNT_T_TYPE, __TIME_T_TYPE) all follow the pattern where the kernel has an old 32-bit type and a new 64-bit type, but the kernel tries not to expose the 32-bit interfaces to user space on new architectures and only provide the 64-bit replacements, but there are a couple of interfaces that never got replaced, typically in driver and file system ioctls. Since glibc already has code to deal with the 64-bit types and that is well tested, it would seem safer to me to just #undef the old types completely rather than defining them to 64-bit, which would make them incompatible with the kernel's types. Arnd 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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 647A4C0650E for ; Thu, 4 Jul 2019 09:19:41 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3899021882 for ; Thu, 4 Jul 2019 09:19:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="KDAIHQ8E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3899021882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Vl7LG0Cf9otvDZW7VZ2HyIMYE2G6vCIjwR48bKBGOXE=; b=KDAIHQ8EJwDOnL JcQKv+VoGtUCmX8FmPU9Ro29EzS+or9hEiY4+3+aN7UqkCkYPQQAXNhTX2HhX2tz2SqwnGjr/mjbV ukLTJ/+WF6NBuLsYWBthC3BwL/uFh4dBoEinn42ATIXvzldbi3AnyVMhGO8CdCv+QTjfcvYujkr6S 0Wg+TGWHbDzuXyBmf1mJH0AxVh5hbuj8WLsSFg8K2hB6u8hbqrexM+fHV/FULU2+MGmWEwie7v8cf 8aPUMsGAz9/F6yiStbCeGJBSAZK76oPQc8Q2/1+P4SXBeQAg8lmKSWCOLBCxuYJGNq00nKekqFPj2 wzN5i7tLsGRPOqhhqhYA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hixtv-0005wS-MD; Thu, 04 Jul 2019 09:19:35 +0000 Received: from mail-qt1-f194.google.com ([209.85.160.194]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hixts-0005vX-Kr for linux-riscv@lists.infradead.org; Thu, 04 Jul 2019 09:19:34 +0000 Received: by mail-qt1-f194.google.com with SMTP id w17so4174752qto.10 for ; Thu, 04 Jul 2019 02:19:30 -0700 (PDT) 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=UU1LRzgJ9KtlIamPG1rpTOdBbiRt377kXD3IRu4KTEc=; b=ExnruZHg1FIxzbSSsgUL5CDc2Q7HDjY745czXVoV2Z9MSzJY/CAKvvBcd2q2plW8Z9 Xhu6g6DUSMI46g8jE/0tZWSjr/3T4zPDo2LQGzIAApASzyH74pyOP0BspX+5FPQsIVt+ QlMT4SXA1kplPH/9dKHqXBCGN4Odeq3ktIzhaTSrvNQtUBY6jIW/7zdH0W4/XSzngWmU aVas3TzvjDI5GirofLapMArx6cUMSYAVoziqULePAmzSpBwASOhm2Gb50/XVEO5TqycQ tI+wdJVzuM+E/84+g/gfuAxpGyBEcdNR3XqVsdKOdM90aQtOwTk4TYGFH6hbr6+bWr8o KNFg== X-Gm-Message-State: APjAAAWu6N2m2w4G9un8zKbPjYZlwkFPTlVjCl+D5mawJeIOB17mEJWh yj4Xxw/m6GpZTwW7eGxt8tDDj8DicsrUkMc06wc= X-Google-Smtp-Source: APXvYqz9HnBRmgYL+EgQde6QoC+3TNiwekg2y+kqVusM0V3Keg/hNYgvdDkMLVnEv4+p3P8DAILsb6JwSzdx30DpREE= X-Received: by 2002:aed:3363:: with SMTP id u90mr2705494qtd.7.1562231969777; Thu, 04 Jul 2019 02:19:29 -0700 (PDT) MIME-Version: 1.0 References: <20190703005202.7578-1-alistair.francis@wdc.com> In-Reply-To: From: Arnd Bergmann Date: Thu, 4 Jul 2019 11:19:13 +0200 Message-ID: Subject: Re: [PATCH RESEND 0/2] RISC-V: Handle the siginfo_t offset problem To: Andreas Schwab X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190704_021932_687552_10E2D2D0 X-CRM114-Status: GOOD ( 17.46 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alistair Francis , linux-riscv@lists.infradead.org, Alistair Francis , Linux Kernel Mailing List Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On Thu, Jul 4, 2019 at 9:20 AM Andreas Schwab wrote: > > On Jul 03 2019, Alistair Francis wrote: > > > On Wed, Jul 3, 2019 at 12:08 AM Andreas Schwab wrote: > >> > >> On Jul 02 2019, Alistair Francis wrote: > >> > >> > In the RISC-V 32-bit glibc port [1] the siginfo_t struct in the kernel > >> > doesn't line up with the struct in glibc. In glibc world the _sifields > >> > union is 8 byte alligned (although I can't figure out why) > >> > >> Try ptype/o in gdb. > > > > That's a useful tip, I'll be sure to use that next time. > > It was a serious note. If the structs don't line up then there is a > mismatch in types that cannot be solved by adding spurious padding. You > need to fix the types instead. Would it be an option to align all the basic typedefs (off_t, time_t, clock_t, ...) between glibc and kernel then, and just use the existing sysdeps/unix/sysv/linux/generic/bits/typesizes.h after all to avoid surprises like this? As of v2 the functional difference is -#define __INO_T_TYPE __ULONGWORD_TYPE +#define __INO_T_TYPE __UQUAD_TYPE #define __INO64_T_TYPE __UQUAD_TYPE #define __MODE_T_TYPE __U32_TYPE -#define __NLINK_T_TYPE __U32_TYPE -#define __OFF_T_TYPE __SLONGWORD_TYPE +#define __NLINK_T_TYPE __UQUAD_TYPE +#define __OFF_T_TYPE __SQUAD_TYPE #define __OFF64_T_TYPE __SQUAD_TYPE -#define __RLIM_T_TYPE __ULONGWORD_TYPE +#define __RLIM_T_TYPE __UQUAD_TYPE #define __RLIM64_T_TYPE __UQUAD_TYPE -#define __BLKCNT_T_TYPE __SLONGWORD_TYPE +#define __BLKCNT_T_TYPE __SQUAD_TYPE #define __BLKCNT64_T_TYPE __SQUAD_TYPE -#define __FSBLKCNT_T_TYPE __ULONGWORD_TYPE +#define __FSBLKCNT_T_TYPE __UQUAD_TYPE #define __FSBLKCNT64_T_TYPE __UQUAD_TYPE -#define __FSFILCNT_T_TYPE __ULONGWORD_TYPE +#define __FSFILCNT_T_TYPE __UQUAD_TYPE #define __FSFILCNT64_T_TYPE __UQUAD_TYPE -#define __FSWORD_T_TYPE __SWORD_TYPE +#define __FSWORD_T_TYPE __SQUAD_TYPE -#define __CLOCK_T_TYPE __SLONGWORD_TYPE -#define __TIME_T_TYPE __SLONGWORD_TYPE +#define __CLOCK_T_TYPE __SQUAD_TYPE +#define __TIME_T_TYPE __SQUAD_TYPE #define __USECONDS_T_TYPE __U32_TYPE -#define __SUSECONDS_T_TYPE __SLONGWORD_TYPE +#define __SUSECONDS_T_TYPE __SQUAD_TYPE -#define __BLKSIZE_T_TYPE __S32_TYPE +#define __BLKSIZE_T_TYPE __SQUAD_TYPE #define __FSID_T_TYPE struct { int __val[2]; } #define __SSIZE_T_TYPE __SWORD_TYPE -#define __SYSCALL_SLONG_TYPE __SLONGWORD_TYPE -#define __SYSCALL_ULONG_TYPE __ULONGWORD_TYPE -#define __CPU_MASK_TYPE __ULONGWORD_TYPE +#define __SYSCALL_SLONG_TYPE __SQUAD_TYPE +#define __SYSCALL_ULONG_TYPE __UQUAD_TYPE +#define __CPU_MASK_TYPE __UQUAD_TYPE -#ifdef __LP64__ # define __RLIM_T_MATCHES_RLIM64_T 1 -#else -# define __RLIM_T_MATCHES_RLIM64_T 0 -#endif +#define __ASSUME_TIME64_SYSCALLS 1 +#define __ASSUME_RLIM64_SYSCALLS 1 Since the sysdeps/unix/sysv/linux/generic/bits/typesizes.h definitions generally match the kernel, anything diverging from that has the potential of breaking it, so the difference should probably be kept to the absolute minimum. I think these ones are wrong and will cause bugs similar to the clock_t issue if they are used with kernel interfaces: __NLINK_T_TYPE, __FSWORD_T_TYPE, __CLOCK_T_TYPE, __BLKSIZE_T_TYPE, __SYSCALL_ULONG_TYPE, __SYSCALL_SLONG_TYPE, __CPU_MASK_TYPE These are fine as long as they are only used in user space and to wrap kernel syscalls, but I think most of them can end up being passed to the kernel, so it seems safer not to have rv32 diverge without a good reason. The remaining ones (__INO_T_TYPE, __OFF_T_TYPE, __BLKCNT_T_TYPE, __FSBLKCNT_T_TYPE, __FSFILCNT_T_TYPE, __TIME_T_TYPE) all follow the pattern where the kernel has an old 32-bit type and a new 64-bit type, but the kernel tries not to expose the 32-bit interfaces to user space on new architectures and only provide the 64-bit replacements, but there are a couple of interfaces that never got replaced, typically in driver and file system ioctls. Since glibc already has code to deal with the 64-bit types and that is well tested, it would seem safer to me to just #undef the old types completely rather than defining them to 64-bit, which would make them incompatible with the kernel's types. Arnd _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv