From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <libc-alpha-return-74510-listarch-libc-alpha=sources.redhat.com@sourceware.org>
Received: (qmail 122300 invoked by alias); 8 Nov 2016 01:20:19 -0000
Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <libc-alpha.sourceware.org>
List-Subscribe: <mailto:libc-alpha-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/libc-alpha/>
List-Post: <mailto:libc-alpha@sourceware.org>
List-Help: <mailto:libc-alpha-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: libc-alpha-owner@sourceware.org
Received: (qmail 122276 invoked by uid 89); 8 Nov 2016 01:20:16 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=0.2 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RDNS_DYNAMIC,TVD_RCVD_IP,URIBL_RED autolearn=no version=3.3.2 spammy=hoped
X-HELO: brightrain.aerifal.cx
Date: Tue, 08 Nov 2016 01:20:00 -0000
From: Rich Felker <dalias@libc.org>
To: Joseph Myers <joseph@codesourcery.com>
Cc: libc-alpha@sourceware.org
Subject: Re: Make SH ucontext always match current kernels
Message-ID: <20161108012001.GA12267@brightrain.aerifal.cx>
References: <alpine.DEB.2.20.1611072317460.23588@digraph.polyomino.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.20.1611072317460.23588@digraph.polyomino.org.uk>
User-Agent: Mutt/1.5.21 (2010-09-15)
X-SW-Source: 2016-11/txt/msg00263.txt.bz2

On Mon, Nov 07, 2016 at 11:18:32PM +0000, Joseph Myers wrote:
> As discussed in the thread starting at
> <https://sourceware.org/ml/libc-alpha/2015-06/msg00657.html>, there
> are various problems with the sigcontext / mcontext / ucontext
> structures on SH.  The soft-float SH4 case in fact does not build at
> present, with errors processing
> sysdeps/unix/sysv/linux/sh/sh4/ucontext_i.sym with gen-as-const.awk
> ("error: 'mcontext_t {aka struct <anonymous>}' has no member named
> 'fpregs'").
> 
> Linux 4.8 (commit bbe6c77857c38f4acbdc4fc70399515226d1859a) moved to
> always using the same sigcontext structure on SH, with room for
> floating-point registers whether or not present on the processor.
> This patch makes the glibc header match.
> 
> Tested (compilation only) for sh4-linux-gnu hard float, and in
> conjunction with other fixes for soft float.
> 
> 2016-11-07  Joseph Myers  <joseph@codesourcery.com>
> 
> 	* sysdeps/unix/sysv/linux/sh/sys/ucontext.h [__SH4__ || __SH4A__]:
> 	Make code unconditional.
> 	[!(__SH4__ || __SH4A__)]: Remove conditional code.
> 
> diff --git a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
> index 2c5fa04..4ee0b28 100644
> --- a/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
> +++ b/sysdeps/unix/sysv/linux/sh/sys/ucontext.h
> @@ -76,7 +76,6 @@ enum
>  };
>  #endif
>  
> -#if (defined(__SH4__) || defined(__SH4A__))
>  typedef int freg_t;
>  
>  /* Number of FPU registers.  */
> @@ -102,20 +101,6 @@ typedef struct
>      unsigned int fpul;
>      unsigned int ownedfp;
>    } mcontext_t;
> -#else
> -/* Context to describe whole processor state.  */
> -typedef struct
> -  {
> -    unsigned int oldmask;
> -    gregset_t gregs;
> -    unsigned int pc;
> -    unsigned int pr;
> -    unsigned int sr;
> -    unsigned int gbr;
> -    unsigned int mach;
> -    unsigned int macl;
> -  } mcontext_t;
> -#endif /* __SH_FPU_ANY__ */
>  
>  /* Userlevel context.  */
>  typedef struct ucontext

I haven't tested the patch, but it looks like the change I
expected/hoped to see glibc make when working on the kernel side.
Thanks.

Rich