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Re: Make SH ucontext always match current kernels
- From: Rich Felker <dalias at libc dot org>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 7 Nov 2016 20:20:01 -0500
- Subject: Re: Make SH ucontext always match current kernels
- Authentication-results: sourceware.org; auth=none
- References: <alpine.DEB.2.20.1611072317460.23588@digraph.polyomino.org.uk>
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