linux-kernel - Re: [PATCH RFC] Update kernel math-emu code from current glibc soft-fp

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Message-ID: <alpine.DEB.2.10.1502191835490.22905@digraph.polyomino.org.uk>
Date:	Thu, 19 Feb 2015 18:40:34 +0000
From:	Joseph Myers <joseph@...esourcery.com>
To:	David Miller <davem@...emloft.net>
CC:	<linux-kernel@...r.kernel.org>, <linux-alpha@...r.kernel.org>,
	<linuxppc-dev@...ts.ozlabs.org>, <linux-s390@...r.kernel.org>,
	<linux-sh@...r.kernel.org>, <sparclinux@...r.kernel.org>,
	<kkojima@...iij4u.or.jp>
Subject: Re: [PATCH RFC] Update kernel math-emu code from current glibc
 soft-fp

On Thu, 19 Feb 2015, David Miller wrote:

> From: Joseph Myers <joseph@...esourcery.com>
> Date: Fri, 6 Feb 2015 17:25:29 +0000
> 
> > * On SPARC, comparisons now use raw unpacking (this should not in fact
> >   change how the emulation behaves, just make it more efficient).
> 
> I did a sparc64 test build and it failed like so:
> 
> arch/sparc/math-emu/math_64.c: In function ‘do_mathemu’:
> arch/sparc/math-emu/math_64.c:487:1: error: expected expression before ‘return’
> arch/sparc/math-emu/math_64.c:488:1: error: expected expression before ‘return’
> arch/sparc/math-emu/math_64.c:490:1: error: expected expression before ‘return’
> arch/sparc/math-emu/math_64.c:491:1: error: expected expression before ‘return’
> arch/sparc/math-emu/math_64.c:495:1: error: expected expression before ‘return’
> 
> I'm attaching a CPP processed math_64.c for your convenience:

Please try this patch on top of the previous one.  The way abort is 
redefined in the kernel code doesn't work for one place using it in an 
expression; this patch changes a comma expression to a statement 
expression.  This didn't appear in my powerpc testing because the powerpc 
emulation never uses FP_FROM_INT; I'm not sure how Kaz's sh testing 
avoided the problem appearing there.

diff --git a/include/math-emu/op-common.h b/include/math-emu/op-common.h
index b9f5e1a..8c059c3 100644
--- a/include/math-emu/op-common.h
+++ b/include/math-emu/op-common.h
@@ -1818,7 +1818,7 @@
 			 X##_e = (_FP_EXPBIAS_##fs + 2 * _FP_W_TYPE_SIZE - 1 \
 				  - _FP_FROM_INT_lz);			\
 		       })						\
-		     : (abort (), 0)));					\
+		     : ({ abort (); 0; })));				\
 									\
 	  if ((rsize) - 1 + _FP_EXPBIAS_##fs >= _FP_EXPMAX_##fs		\
 	      && X##_e >= _FP_EXPMAX_##fs)				\

-- 
Joseph S. Myers
joseph@...esourcery.com