alpha: reorganize copy_process(), prepare to saner fork_idle()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 14 insertions, 21 deletions

diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index ad86c099b6f5..a4dc79ba030f 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -266,18 +266,22 @@ alpha_vfork(void)
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
             unsigned long arg,
-            struct task_struct * p, struct pt_regs * regs)
+            struct task_struct *p, struct pt_regs *wontuse)
 {
         extern void ret_from_fork(void);
         extern void ret_from_kernel_thread(void);
 
         struct thread_info *childti = task_thread_info(p);
         struct pt_regs *childregs = task_pt_regs(p);
+        struct pt_regs *regs = current_pt_regs();
         struct switch_stack *childstack, *stack;
         unsigned long settls;
 
         childstack = ((struct switch_stack *) childregs) - 1;
-        if (unlikely(!regs)) {
+        childti->pcb.ksp = (unsigned long) childstack;
+        childti->pcb.flags = 1; /* set FEN, clear everything else */
+
+        if (unlikely(p->flags & PF_KTHREAD)) {
                 /* kernel thread */
                 memset(childstack, 0,
                         sizeof(struct switch_stack) + sizeof(struct pt_regs));
@@ -286,12 +290,17 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
                 childstack->r10 = arg;
                 childregs->hae = alpha_mv.hae_cache,
                 childti->pcb.usp = 0;
-                childti->pcb.ksp = (unsigned long) childstack;
-                childti->pcb.flags = 1; /* set FEN, clear everything else */
                 return 0;
         }
+        /* Note: if CLONE_SETTLS is not set, then we must inherit the
+           value from the parent, which will have been set by the block
+           copy in dup_task_struct.  This is non-intuitive, but is
+           required for proper operation in the case of a threaded
+           application calling fork.  */
+        if (clone_flags & CLONE_SETTLS)
+                childti->pcb.unique = regs->r20;
+        childti->pcb.usp = usp ?: rdusp();
         *childregs = *regs;
-        settls = regs->r20;
         childregs->r0 = 0;
         childregs->r19 = 0;
         childregs->r20 = 1;     /* OSF/1 has some strange fork() semantics.  */
@@ -299,22 +308,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
         stack = ((struct switch_stack *) regs) - 1;
         *childstack = *stack;
         childstack->r26 = (unsigned long) ret_from_fork;
-        childti->pcb.usp = usp ?: rdusp();
-        childti->pcb.ksp = (unsigned long) childstack;
-        childti->pcb.flags = 1; /* set FEN, clear everything else */
-
-        /* Set a new TLS for the child thread?  Peek back into the
-           syscall arguments that we saved on syscall entry.  Oops,
-           except we'd have clobbered it with the parent/child set
-           of r20.  Read the saved copy.  */
-        /* Note: if CLONE_SETTLS is not set, then we must inherit the
-           value from the parent, which will have been set by the block
-           copy in dup_task_struct.  This is non-intuitive, but is
-           required for proper operation in the case of a threaded
-           application calling fork.  */
-        if (clone_flags & CLONE_SETTLS)
-                childti->pcb.unique = settls;
-
         return 0;
 }