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, 20 insertions, 95 deletions

diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index 1bb0a8abd79..fd78f58ea79 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -69,44 +69,6 @@ void machine_restart(char *cmd)
 }
 
 /*
- * PC is actually discarded when returning from a system call -- the
- * return address must be stored in LR. This function will make sure
- * LR points to do_exit before starting the thread.
- *
- * Also, when returning from fork(), r12 is 0, so we must copy the
- * argument as well.
- *
- *  r0 : The argument to the main thread function
- *  r1 : The address of do_exit
- *  r2 : The address of the main thread function
- */
-asmlinkage extern void kernel_thread_helper(void);
-__asm__("	.type	kernel_thread_helper, @function\n"
-	"kernel_thread_helper:\n"
-	"	mov	r12, r0\n"
-	"	mov	lr, r2\n"
-	"	mov	pc, r1\n"
-	"	.size	kernel_thread_helper, . - kernel_thread_helper");
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.r0 = (unsigned long)arg;
-	regs.r1 = (unsigned long)fn;
-	regs.r2 = (unsigned long)do_exit;
-	regs.lr = (unsigned long)kernel_thread_helper;
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.sr = MODE_SUPERVISOR;
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
-		       0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc
  */
 void exit_thread(void)
@@ -332,26 +294,32 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 }
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
+asmlinkage void syscall_return(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;
-
-	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
-	*childregs = *regs;
-
-	if (user_mode(regs))
-		childregs->sp = usp;
-	else
-		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-
-	childregs->r12 = 0; /* Set return value for child */
+	struct pt_regs *childregs = task_pt_regs(p);
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread.cpu_context.r0 = arg;
+		p->thread.cpu_context.r1 = usp; /* fn */
+		p->thread.cpu_context.r2 = syscall_return;
+		p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
+		childregs->sr = MODE_SUPERVISOR;
+	} else {
+		*childregs = *current_pt_regs();
+		if (usp)
+			childregs->sp = usp;
+		childregs->r12 = 0; /* Set return value for child */
+		p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+	}
 
 	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 	p->thread.cpu_context.ksp = (unsigned long)childregs;
-	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 
 	clear_tsk_thread_flag(p, TIF_DEBUG);
 	if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
@@ -360,49 +328,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	return 0;
 }
 
-/* r12-r8 are dummy parameters to force the compiler to use the stack */
-asmlinkage int sys_fork(struct pt_regs *regs)
-{
-	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
-}
-
-asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
-		void __user *parent_tidptr, void __user *child_tidptr,
-		struct pt_regs *regs)
-{
-	if (!newsp)
-		newsp = regs->sp;
-	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr,
-			child_tidptr);
-}
-
-asmlinkage int sys_vfork(struct pt_regs *regs)
-{
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
-		       0, NULL, NULL);
-}
-
-asmlinkage int sys_execve(const char __user *ufilename,
-			  const char __user *const __user *uargv,
-			  const char __user *const __user *uenvp,
-			  struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(ufilename);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name, uargv, uenvp, regs);
-	putname(filename);
-
-out:
-	return error;
-}
-
-
 /*
  * This function is supposed to answer the question "who called
  * schedule()?"