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Re: [musl] SH sigcontext ABI is broken
- From: Rob Landley <rob at landley dot net>
- To: Joseph Myers <joseph at codesourcery dot com>, Rich Felker <dalias at libc dot org>
- Cc: musl at lists dot openwall dot com, libc-alpha at sourceware dot org, linux-sh at vger dot kernel dot org
- Date: Wed, 24 Jun 2015 03:23:33 -0500
- Subject: Re: [musl] SH sigcontext ABI is broken
- Authentication-results: sourceware.org; auth=none
- References: <20150619070912 dot GA15025 at brightrain dot aerifal dot cx> <20150620180644 dot GY1173 at brightrain dot aerifal dot cx> <558A3124 dot 30701 at landley dot net> <20150624045224 dot GO1173 at brightrain dot aerifal dot cx> <alpine dot DEB dot 2 dot 10 dot 1506241400040 dot 6710 at digraph dot polyomino dot org dot uk>
On 06/24/2015 09:10 AM, Joseph Myers wrote:
> On Wed, 24 Jun 2015, Rich Felker wrote:
>
>> Nominally SH3 support remains in both the kernel and glibc. If it can
>> be established that multiple parties agree that there's really no one
>> left who cares about the old no-FPU sigcontext ABI on SH3, I will be
>> all for dropping it and unifying sigcontext.
>
> Note that right now we have BE and LE versions of *three* ABIs for SH in
> glibc (SH3 soft-float, SH4 soft-float, SH4 hard-float) (and as noted in
> this discussion, right now each would only work properly on a kernel with
> the corresponding configuration). See
> <https://sourceware.org/glibc/wiki/ABIList>.
>
> We can, of course, choose to declare processor or ABI variants no longer
> supported in glibc, much like we desupported i386 in glibc (requiring i486
> or later - albeit the official desupporting happening several years after
> i386 would no longer build) or removed support for non-EABI ARM. But
> since we don't have an SH maintainer at all in glibc at present, it's
> harder to make such a decision (whereas if an architecture maintainer
> decided some variants were no longer relevant, they could just remove
> support - make those variants give a configure-time error - in the absence
> of someone objecting and willing to take over maintaining support for
> those variants).
>
> I think the next glibc change likely to require action from each
> architecture's maintainer to avoid breaking the build may be Adhemerval's
> cancellation changes - so if no-one comes forward as SH maintainer to at
> least update SH for those changes when they are ready to go in, the build
> for SH will be broken and that will indicate, as per
> <https://sourceware.org/ml/libc-alpha/2015-06/msg00424.html>, that it may
> be time to remove the port from glibc.
Eh, ping me when that happens. I may at least do necessary changes to
keep it building. (Although I can only test glibc on qemu-system-sh4.)
Rob