[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, 6 insertions, 0 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 0e1c95074d42..0b515ac53134 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -885,6 +885,12 @@ int flush_old_exec(struct linux_binprm * bprm)
         current->flags &= ~PF_RANDOMIZE;
         flush_thread();
 
+        /* Set the new mm task size. We have to do that late because it may
+         * depend on TIF_32BIT which is only updated in flush_thread() on
+         * some architectures like powerpc
+         */
+        current->mm->task_size = TASK_SIZE;
+
         if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 
             file_permission(bprm->file, MAY_READ) ||
             (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {