1 files changed, 60 insertions, 101 deletions

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 35e106f2ed13..31360cbbd5f8 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -393,72 +393,24 @@ ia64_load_extra (struct task_struct *task)
 int
 copy_thread(unsigned long clone_flags,
              unsigned long user_stack_base, unsigned long user_stack_size,
-             struct task_struct *p, struct pt_regs *regs)
+             struct task_struct *p)
 {
         extern char ia64_ret_from_clone;
         struct switch_stack *child_stack, *stack;
         unsigned long rbs, child_rbs, rbs_size;
         struct pt_regs *child_ptregs;
+        struct pt_regs *regs = current_pt_regs();
         int retval = 0;
 
-#ifdef CONFIG_SMP
-        /*
-         * For SMP idle threads, fork_by_hand() calls do_fork with
-         * NULL regs.
-         */
-        if (!regs)
-                return 0;
-#endif
-
-        stack = ((struct switch_stack *) regs) - 1;
-
         child_ptregs = (struct pt_regs *) ((unsigned long) p + IA64_STK_OFFSET) - 1;
         child_stack = (struct switch_stack *) child_ptregs - 1;
 
-        /* copy parent's switch_stack & pt_regs to child: */
-        memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
-
         rbs = (unsigned long) current + IA64_RBS_OFFSET;
         child_rbs = (unsigned long) p + IA64_RBS_OFFSET;
-        rbs_size = stack->ar_bspstore - rbs;
-
-        /* copy the parent's register backing store to the child: */
-        memcpy((void *) child_rbs, (void *) rbs, rbs_size);
-
-        if (likely(user_mode(child_ptregs))) {
-                if (clone_flags & CLONE_SETTLS)
-                        child_ptregs->r13 = regs->r16;  /* see sys_clone2() in entry.S */
-                if (user_stack_base) {
-                        child_ptregs->r12 = user_stack_base + user_stack_size - 16;
-                        child_ptregs->ar_bspstore = user_stack_base;
-                        child_ptregs->ar_rnat = 0;
-                        child_ptregs->loadrs = 0;
-                }
-        } else {
-                /*
-                 * Note: we simply preserve the relative position of
-                 * the stack pointer here.  There is no need to
-                 * allocate a scratch area here, since that will have
-                 * been taken care of by the caller of sys_clone()
-                 * already.
-                 */
-                child_ptregs->r12 = (unsigned long) child_ptregs - 16; /* kernel sp */
-                child_ptregs->r13 = (unsigned long) p;          /* set `current' pointer */
-        }
-        child_stack->ar_bspstore = child_rbs + rbs_size;
-        child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
 
         /* copy parts of thread_struct: */
         p->thread.ksp = (unsigned long) child_stack - 16;
 
-        /* stop some PSR bits from being inherited.
-         * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
-         * therefore we must specify them explicitly here and not include them in
-         * IA64_PSR_BITS_TO_CLEAR.
-         */
-        child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
-                                 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
-
         /*
          * NOTE: The calling convention considers all floating point
          * registers in the high partition (fph) to be scratch.  Since
@@ -480,8 +432,66 @@ copy_thread(unsigned long clone_flags,
 #       define THREAD_FLAGS_TO_SET      0
         p->thread.flags = ((current->thread.flags & ~THREAD_FLAGS_TO_CLEAR)
                            | THREAD_FLAGS_TO_SET);
+
         ia64_drop_fpu(p);       /* don't pick up stale state from a CPU's fph */
 
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                if (unlikely(!user_stack_base)) {
+                        /* fork_idle() called us */
+                        return 0;
+                }
+                memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
+                child_stack->r4 = user_stack_base;      /* payload */
+                child_stack->r5 = user_stack_size;      /* argument */
+                /*
+                 * Preserve PSR bits, except for bits 32-34 and 37-45,
+                 * which we can't read.
+                 */
+                child_ptregs->cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
+                /* mark as valid, empty frame */
+                child_ptregs->cr_ifs = 1UL << 63;
+                child_stack->ar_fpsr = child_ptregs->ar_fpsr
+                        = ia64_getreg(_IA64_REG_AR_FPSR);
+                child_stack->pr = (1 << PRED_KERNEL_STACK);
+                child_stack->ar_bspstore = child_rbs;
+                child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+                /* stop some PSR bits from being inherited.
+                 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+                 * therefore we must specify them explicitly here and not include them in
+                 * IA64_PSR_BITS_TO_CLEAR.
+                 */
+                child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+                                 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
+
+                return 0;
+        }
+        stack = ((struct switch_stack *) regs) - 1;
+        /* copy parent's switch_stack & pt_regs to child: */
+        memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
+
+        /* copy the parent's register backing store to the child: */
+        rbs_size = stack->ar_bspstore - rbs;
+        memcpy((void *) child_rbs, (void *) rbs, rbs_size);
+        if (clone_flags & CLONE_SETTLS)
+                child_ptregs->r13 = regs->r16;  /* see sys_clone2() in entry.S */
+        if (user_stack_base) {
+                child_ptregs->r12 = user_stack_base + user_stack_size - 16;
+                child_ptregs->ar_bspstore = user_stack_base;
+                child_ptregs->ar_rnat = 0;
+                child_ptregs->loadrs = 0;
+        }
+        child_stack->ar_bspstore = child_rbs + rbs_size;
+        child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+        /* stop some PSR bits from being inherited.
+         * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+         * therefore we must specify them explicitly here and not include them in
+         * IA64_PSR_BITS_TO_CLEAR.
+         */
+        child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+                                 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
+
 #ifdef CONFIG_PERFMON
         if (current->thread.pfm_context)
                 pfm_inherit(p, child_ptregs);
@@ -608,57 +618,6 @@ dump_fpu (struct pt_regs *pt, elf_fpregset_t dst)
         return 1;       /* f0-f31 are always valid so we always return 1 */
 }
 
-long
-sys_execve (const char __user *filename,
-            const char __user *const __user *argv,
-            const char __user *const __user *envp,
-            struct pt_regs *regs)
-{
-        struct filename *fname;
-        int error;
-
-        fname = getname(filename);
-        error = PTR_ERR(fname);
-        if (IS_ERR(fname))
-                goto out;
-        error = do_execve(fname->name, argv, envp, regs);
-        putname(fname);
-out:
-        return error;
-}
-
-pid_t
-kernel_thread (int (*fn)(void *), void *arg, unsigned long flags)
-{
-        extern void start_kernel_thread (void);
-        unsigned long *helper_fptr = (unsigned long *) &start_kernel_thread;
-        struct {
-                struct switch_stack sw;
-                struct pt_regs pt;
-        } regs;
-
-        memset(&regs, 0, sizeof(regs));
-        regs.pt.cr_iip = helper_fptr[0];        /* set entry point (IP) */
-        regs.pt.r1 = helper_fptr[1];            /* set GP */
-        regs.pt.r9 = (unsigned long) fn;        /* 1st argument */
-        regs.pt.r11 = (unsigned long) arg;      /* 2nd argument */
-        /* Preserve PSR bits, except for bits 32-34 and 37-45, which we can't read.  */
-        regs.pt.cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
-        regs.pt.cr_ifs = 1UL << 63;             /* mark as valid, empty frame */
-        regs.sw.ar_fpsr = regs.pt.ar_fpsr = ia64_getreg(_IA64_REG_AR_FPSR);
-        regs.sw.ar_bspstore = (unsigned long) current + IA64_RBS_OFFSET;
-        regs.sw.pr = (1 << PRED_KERNEL_STACK);
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs.pt, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/* This gets called from kernel_thread() via ia64_invoke_thread_helper().  */
-int
-kernel_thread_helper (int (*fn)(void *), void *arg)
-{
-        return (*fn)(arg);
-}
-
 /*
  * Flush thread state.  This is called when a thread does an execve().
  */