Sanitize the type of struct user.u_ar0

struct user.u_ar0 is defined to contain a pointer offset on all
architectures in which it is defined (all architectures which define an
a.out format except SPARC.) However, it has a pointer type in the headers,
which is pointless -- <asm/user.h> is not exported to userspace, and it
just makes the code messy.

Redefine the field as "unsigned long" (which is the same size as a pointer
on all Linux architectures) and change the setting code to user offsetof()
instead of hand-coded arithmetic.

Cc: Linux Arch Mailing List <linux-arch@vger.kernel.org>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Lennert Buytenhek <kernel@wantstofly.org>
Cc: Håvard Skinnemoen <hskinnemoen@atmel.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-x86/user_32.h b/include/asm-x86/user_32.h
index ed8b8fc6906c..6157da6f882c 100644
--- a/include/asm-x86/user_32.h
+++ b/include/asm-x86/user_32.h
@@ -116,7 +116,7 @@ struct user{
                                    esp register.  */
   long int signal;              /* Signal that caused the core dump. */
   int reserved;                 /* No longer used */
-  struct user_pt_regs * u_ar0;  /* Used by gdb to help find the values for */
+  unsigned long u_ar0;          /* Used by gdb to help find the values for */
                                 /* the registers. */
   struct user_i387_struct* u_fpstate;   /* Math Co-processor pointer. */
   unsigned long magic;          /* To uniquely identify a core file */
diff --git a/include/asm-x86/user_64.h b/include/asm-x86/user_64.h
index a5449d456cc0..963616455609 100644
--- a/include/asm-x86/user_64.h
+++ b/include/asm-x86/user_64.h
@@ -118,7 +118,7 @@ struct user{
   long int signal;              /* Signal that caused the core dump. */
   int reserved;                 /* No longer used */
   int pad1;
-  struct user_pt_regs * u_ar0;  /* Used by gdb to help find the values for */
+  unsigned long u_ar0;          /* Used by gdb to help find the values for */
                                 /* the registers. */
   struct user_i387_struct* u_fpstate;   /* Math Co-processor pointer. */
   unsigned long magic;          /* To uniquely identify a core file */