rename thread_info to stack

This finally renames the thread_info field in task structure to stack, so that
the assumptions about this field are gone and archs have more freedom about
placing the thread_info structure.

Nonbroken archs which have a proper thread pointer can do the access to both
current thread and task structure via a single pointer.

It'll allow for a few more cleanups of the fork code, from which e.g.  ia64
could benefit.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
[akpm@linux-foundation.org: build fix]
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Andi Kleen <ak@muc.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-alpha/thread_info.h b/include/asm-alpha/thread_info.h
index eeb3bef..f4defc2 100644
--- a/include/asm-alpha/thread_info.h
+++ b/include/asm-alpha/thread_info.h
@@ -97,7 +97,7 @@
 				 1 << TIF_UAC_SIGBUS)
 
 #define SET_UNALIGN_CTL(task,value)	({				     \
-	(task)->thread_info->flags = (((task)->thread_info->flags &	     \
+	task_thread_info(task)->flags = ((task_thread_info(task)->flags &    \
 		~ALPHA_UAC_MASK)					     \
 		| (((value) << ALPHA_UAC_SHIFT)       & (1<<TIF_UAC_NOPRINT))\
 		| (((value) << (ALPHA_UAC_SHIFT + 1)) & (1<<TIF_UAC_SIGBUS)) \
@@ -105,11 +105,11 @@
 	0; })
 
 #define GET_UNALIGN_CTL(task,value)	({				\
-	put_user(((task)->thread_info->flags & (1 << TIF_UAC_NOPRINT))	\
+	put_user((task_thread_info(task)->flags & (1 << TIF_UAC_NOPRINT))\
 		  >> ALPHA_UAC_SHIFT					\
-		 | ((task)->thread_info->flags & (1 << TIF_UAC_SIGBUS))	\
+		 | (task_thread_info(task)->flags & (1 << TIF_UAC_SIGBUS))\
 		 >> (ALPHA_UAC_SHIFT + 1)				\
-		 | ((task)->thread_info->flags & (1 << TIF_UAC_NOFIX))	\
+		 | (task_thread_info(task)->flags & (1 << TIF_UAC_NOFIX))\
 		 >> (ALPHA_UAC_SHIFT - 1),				\
 		 (int __user *)(value));				\
 	})