flagday: don't pass regs to copy_thread()

[deliverable/linux.git] / arch / microblaze / kernel / process.c

diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 1944e00f07e1d4185cbf8bbdf894591192ef6abd..40823fd1db0bb915c87ef33650166281660ddf58 100644 (file)
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -13,6 +13,7 @@
 #include <linux/pm.h>
 #include <linux/tick.h>
 #include <linux/bitops.h>
+#include <linux/ptrace.h>
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h> /* for USER_DS macros */
 #include <asm/cacheflush.h>
@@ -119,46 +120,38 @@ void flush_thread(void)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-               unsigned long unused,
-               struct task_struct *p, struct pt_regs *regs)
+               unsigned long arg, struct task_struct *p)
 {
        struct pt_regs *childregs = task_pt_regs(p);
        struct thread_info *ti = task_thread_info(p);
 
-       *childregs = *regs;
-       if (user_mode(regs))
+       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 = *current_pt_regs();
+       if (usp)
                childregs->r1 = usp;
-       else
-               childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
 
-#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 +202,6 @@ 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 +216,7 @@ 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
 }