[PATCH] powerpc: task_stack_page()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index bc03526d25de..1f816f0d7740 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -503,7 +503,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 {
         struct pt_regs *childregs, *kregs;
         extern void ret_from_fork(void);
-        unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
+        unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 
         CHECK_FULL_REGS(regs);
         /* Copy registers */
@@ -588,10 +588,8 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
          * set.  Do it now.
          */
         if (!current->thread.regs) {
-                unsigned long childregs = (unsigned long)current->thread_info +
-                                                THREAD_SIZE;
-                childregs -= sizeof(struct pt_regs);
-                current->thread.regs = (struct pt_regs *)childregs;
+                struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
+                current->thread.regs = regs - 1;
         }
 
         memset(regs->gpr, 0, sizeof(regs->gpr));
@@ -767,7 +765,7 @@ out:
 static int validate_sp(unsigned long sp, struct task_struct *p,
                        unsigned long nbytes)
 {
-        unsigned long stack_page = (unsigned long)p->thread_info;
+        unsigned long stack_page = (unsigned long)task_stack_page(p);
 
         if (sp >= stack_page + sizeof(struct thread_struct)
             && sp <= stack_page + THREAD_SIZE - nbytes)