[PATCH] Add mm->task_size and fix powerpc vdso

This patch adds mm->task_size to keep track of the task size of a given mm
and uses that to fix the powerpc vdso so that it uses the mm task size to
decide what pages to fault in instead of the current thread flags (which
broke when ptracing).

(akpm: I expect that mm_struct.task_size will become the way in which we
finally sort out the confusion between 32-bit processes and 32-bit mm's.  It
may need tweaks, but at this stage this patch is powerpc-only.)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index f0c47dab0903..04f7df39ffbb 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -182,8 +182,8 @@ static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
         unsigned long offset = address - vma->vm_start;
         struct page *pg;
 #ifdef CONFIG_PPC64
-        void *vbase = test_thread_flag(TIF_32BIT) ?
-                vdso32_kbase : vdso64_kbase;
+        void *vbase = (vma->vm_mm->task_size > TASK_SIZE_USER32) ?
+                vdso64_kbase : vdso32_kbase;
 #else
         void *vbase = vdso32_kbase;
 #endif