maps4: rework TASK_SIZE macros

The following replaces the earlier patches sent.  It should address
David Rientjes's comments, and has been compile tested on all the
architectures that it touches, save for parisc.

For the /proc/<pid>/pagemap code[1], we need to able to query how
much virtual address space a particular task has.  The trick is
that we do it through /proc and can't use TASK_SIZE since it
references "current" on some arches.  The process opening the
/proc file might be a 32-bit process opening a 64-bit process's
pagemap file.

x86_64 already has a TASK_SIZE_OF() macro:

#define TASK_SIZE_OF(child)     ((test_tsk_thread_flag(child, TIF_IA32)) ? IA32_PAGE_OFFSET : TASK_SIZE64)

I'd like to have that for other architectures.  So, add it
for all the architectures that actually use "current" in
their TASK_SIZE.  For the others, just add a quick #define
in sched.h to use plain old TASK_SIZE.

1. http://www.linuxworld.com/news/2007/042407-kernel.html

- MIPS portion from Ralf Baechle <ralf@linux-mips.org>

[akpm@linux-foundation.org: fix mips build]
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Matt Mackall <mpm@selenic.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/asm-s390/processor.h b/include/asm-s390/processor.h
index c86b982aef5..4f744609cd1 100644
--- a/include/asm-s390/processor.h
+++ b/include/asm-s390/processor.h
@@ -70,8 +70,9 @@ extern int get_cpu_capability(unsigned int *);
 
 #else /* __s390x__ */
 
-# define TASK_SIZE		(test_thread_flag(TIF_31BIT) ? \
+# define TASK_SIZE_OF(tsk)	(test_tsk_thread_flag(tsk, TIF_31BIT) ? \
 					(0x80000000UL) : (0x40000000000UL))
+# define TASK_SIZE		TASK_SIZE_OF(current)
 # define TASK_UNMAPPED_BASE	(TASK_SIZE / 2)
 # define DEFAULT_TASK_SIZE	(0x40000000000UL)