1 files changed, 21 insertions, 51 deletions

diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 1944e00f07e1..29768c3dc358 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -119,46 +119,38 @@ void flush_thread(void)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-                unsigned long unused,
+                unsigned long arg,
                 struct task_struct *p, struct pt_regs *regs)
 {
         struct pt_regs *childregs = task_pt_regs(p);
         struct thread_info *ti = task_thread_info(p);
 
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                /* if we're creating a new kernel thread then just zeroing all
+                 * the registers. That's OK for a brand new thread.*/
+                memset(childregs, 0, sizeof(struct pt_regs));
+                memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
+                ti->cpu_context.r1  = (unsigned long)childregs;
+                ti->cpu_context.r20 = (unsigned long)usp; /* fn */
+                ti->cpu_context.r19 = (unsigned long)arg;
+                childregs->pt_mode = 1;
+                local_save_flags(childregs->msr);
+#ifdef CONFIG_MMU
+                ti->cpu_context.msr = childregs->msr & ~MSR_IE;
+#endif
+                ti->cpu_context.r15 = (unsigned long)ret_from_kernel_thread - 8;
+                return 0;
+        }
         *childregs = *regs;
-        if (user_mode(regs))
-                childregs->r1 = usp;
-        else
-                childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
+        childregs->r1 = usp;
 
-#ifndef CONFIG_MMU
         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
         ti->cpu_context.r1 = (unsigned long)childregs;
+#ifndef CONFIG_MMU
         ti->cpu_context.msr = (unsigned long)childregs->msr;
 #else
+        childregs->msr |= MSR_UMS;
 
-        /* if creating a kernel thread then update the current reg (we don't
-         * want to use the parent's value when restoring by POP_STATE) */
-        if (kernel_mode(regs))
-                /* save new current on stack to use POP_STATE */
-                childregs->CURRENT_TASK = (unsigned long)p;
-        /* if returning to user then use the parent's value of this register */
-
-        /* if we're creating a new kernel thread then just zeroing all
-         * the registers. That's OK for a brand new thread.*/
-        /* Pls. note that some of them will be restored in POP_STATE */
-        if (kernel_mode(regs))
-                memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
-        /* if this thread is created for fork/vfork/clone, then we want to
-         * restore all the parent's context */
-        /* in addition to the registers which will be restored by POP_STATE */
-        else {
-                ti->cpu_context = *(struct cpu_context *)regs;
-                childregs->msr |= MSR_UMS;
-        }
-
-        /* FIXME STATE_SAVE_PT_OFFSET; */
-        ti->cpu_context.r1  = (unsigned long)childregs;
         /* we should consider the fact that childregs is a copy of the parent
          * regs which were saved immediately after entering the kernel state
          * before enabling VM. This MSR will be restored in switch_to and
@@ -209,29 +201,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 }
 #endif
 
-static void kernel_thread_helper(int (*fn)(void *), void *arg)
-{
-        fn(arg);
-        do_exit(-1);
-}
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-        /* store them in non-volatile registers */
-        regs.r5 = (unsigned long)fn;
-        regs.r6 = (unsigned long)arg;
-        local_save_flags(regs.msr);
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.pt_mode = 1;
-
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-                        &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL_GPL(kernel_thread);
-
 unsigned long get_wchan(struct task_struct *p)
 {
 /* TBD (used by procfs) */
@@ -246,6 +215,7 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
         regs->pt_mode = 0;
 #ifdef CONFIG_MMU
         regs->msr |= MSR_UMS;
+        regs->msr &= ~MSR_VM;
 #endif
 }