Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull big execve/kernel_thread/fork unification series from Al Viro:
 "All architectures are converted to new model.  Quite a bit of that
  stuff is actually shared with architecture trees; in such cases it's
  literally shared branch pulled by both, not a cherry-pick.

  A lot of ugliness and black magic is gone (-3KLoC total in this one):

   - kernel_thread()/kernel_execve()/sys_execve() redesign.

     We don't do syscalls from kernel anymore for either kernel_thread()
     or kernel_execve():

     kernel_thread() is essentially clone(2) with callback run before we
     return to userland, the callbacks either never return or do
     successful do_execve() before returning.

     kernel_execve() is a wrapper for do_execve() - it doesn't need to
     do transition to user mode anymore.

     As a result kernel_thread() and kernel_execve() are
     arch-independent now - they live in kernel/fork.c and fs/exec.c
     resp.  sys_execve() is also in fs/exec.c and it's completely
     architecture-independent.

   - daemonize() is gone, along with its parts in fs/*.c

   - struct pt_regs * is no longer passed to do_fork/copy_process/
     copy_thread/do_execve/search_binary_handler/->load_binary/do_coredump.

   - sys_fork()/sys_vfork()/sys_clone() unified; some architectures
     still need wrappers (ones with callee-saved registers not saved in
     pt_regs on syscall entry), but the main part of those suckers is in
     kernel/fork.c now."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (113 commits)
  do_coredump(): get rid of pt_regs argument
  print_fatal_signal(): get rid of pt_regs argument
  ptrace_signal(): get rid of unused arguments
  get rid of ptrace_signal_deliver() arguments
  new helper: signal_pt_regs()
  unify default ptrace_signal_deliver
  flagday: kill pt_regs argument of do_fork()
  death to idle_regs()
  don't pass regs to copy_process()
  flagday: don't pass regs to copy_thread()
  bfin: switch to generic vfork, get rid of pointless wrappers
  xtensa: switch to generic clone()
  openrisc: switch to use of generic fork and clone
  unicore32: switch to generic clone(2)
  score: switch to generic fork/vfork/clone
  c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone()
  take sys_fork/sys_vfork/sys_clone prototypes to linux/syscalls.h
  mn10300: switch to generic fork/vfork/clone
  h8300: switch to generic fork/vfork/clone
  tile: switch to generic clone()
  ...

Conflicts:
	arch/microblaze/include/asm/Kbuild

1 files changed, 23 insertions, 52 deletions

diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 1944e00f07e1..40823fd1db0b 100644
--- 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
 }