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

7 files changed, 29 insertions, 157 deletions

diff --git a/arch/score/Kconfig b/arch/score/Kconfig
index 4f93a431a45..45893390c7d 100644
--- a/arch/score/Kconfig
+++ b/arch/score/Kconfig
@@ -13,6 +13,9 @@ config SCORE
        select GENERIC_CLOCKEVENTS
        select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
+	select CLONE_BACKWARDS
 
 choice
 	prompt "System type"
diff --git a/arch/score/include/asm/processor.h b/arch/score/include/asm/processor.h
index ab3aceb5420..d9a922d8711 100644
--- a/arch/score/include/asm/processor.h
+++ b/arch/score/include/asm/processor.h
@@ -13,7 +13,6 @@ struct task_struct;
  */
 extern void (*cpu_wait)(void);
 
-extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 extern void start_thread(struct pt_regs *regs,
 			unsigned long pc, unsigned long sp);
diff --git a/arch/score/include/asm/syscalls.h b/arch/score/include/asm/syscalls.h
index 1dd5e0d6b0c..acaeed68095 100644
--- a/arch/score/include/asm/syscalls.h
+++ b/arch/score/include/asm/syscalls.h
@@ -1,8 +1,6 @@
 #ifndef _ASM_SCORE_SYSCALLS_H
 #define _ASM_SCORE_SYSCALLS_H
 
-asmlinkage long score_clone(struct pt_regs *regs);
-asmlinkage long score_execve(struct pt_regs *regs);
 asmlinkage long score_sigaltstack(struct pt_regs *regs);
 asmlinkage long score_rt_sigreturn(struct pt_regs *regs);
 
diff --git a/arch/score/include/asm/unistd.h b/arch/score/include/asm/unistd.h
index a862384e9c1..56001c93095 100644
--- a/arch/score/include/asm/unistd.h
+++ b/arch/score/include/asm/unistd.h
@@ -4,5 +4,9 @@
 #define __ARCH_WANT_SYSCALL_NO_FLAGS
 #define __ARCH_WANT_SYSCALL_OFF_T
 #define __ARCH_WANT_SYSCALL_DEPRECATED
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_FORK
+#define __ARCH_WANT_SYS_VFORK
 
 #include <asm-generic/unistd.h>
diff --git a/arch/score/kernel/entry.S b/arch/score/kernel/entry.S
index 83bb96079c4..1557ca1a295 100644
--- a/arch/score/kernel/entry.S
+++ b/arch/score/kernel/entry.S
@@ -278,6 +278,13 @@ need_resched:
 	nop
 #endif
 
+ENTRY(ret_from_kernel_thread)
+	bl	schedule_tail			# r4=struct task_struct *prev
+	nop
+	mv	r4, r13
+	brl	r12
+	j	syscall_exit
+
 ENTRY(ret_from_fork)
 	bl	schedule_tail			# r4=struct task_struct *prev
 
@@ -480,16 +487,6 @@ illegal_syscall:
 	sw	r9, [r0, PT_R7]
 	j	syscall_return
 
-ENTRY(sys_execve)
-	mv	r4, r0
-	la	r8, score_execve
-	br	r8
-
-ENTRY(sys_clone)
-	mv	r4, r0
-	la	r8, score_clone
-	br	r8
-
 ENTRY(sys_rt_sigreturn)
 	mv	r4, r0
 	la	r8, score_rt_sigreturn
@@ -499,16 +496,3 @@ ENTRY(sys_sigaltstack)
 	mv	r4, r0
 	la	r8, score_sigaltstack
 	br	r8
-
-#ifdef __ARCH_WANT_SYSCALL_DEPRECATED
-ENTRY(sys_fork)
-	mv	r4, r0
-	la	r8, score_fork
-	br	r8
-
-ENTRY(sys_vfork)
-	mv	r4, r0
-	la	r8, score_vfork
-	br	r8
-#endif /* __ARCH_WANT_SYSCALL_DEPRECATED */
-
diff --git a/arch/score/kernel/process.c b/arch/score/kernel/process.c
index 637970cfd3f..79568466b57 100644
--- a/arch/score/kernel/process.c
+++ b/arch/score/kernel/process.c
@@ -60,6 +60,7 @@ void __noreturn cpu_idle(void)
 }
 
 void ret_from_fork(void);
+void ret_from_kernel_thread(void);
 
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 {
@@ -86,29 +87,27 @@ void flush_thread(void) {}
  * set up the kernel stack and exception frames for a new process
  */
 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 thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs = task_pt_regs(p);
+	struct pt_regs *regs = current_pt_regs();
 
-	p->set_child_tid = NULL;
-	p->clear_child_tid = NULL;
-
-	*childregs = *regs;
-	childregs->regs[7] = 0;		/* Clear error flag */
-	childregs->regs[4] = 0;		/* Child gets zero as return value */
-	regs->regs[4] = p->pid;
-
-	if (childregs->cp0_psr & 0x8) {	/* test kernel fork or user fork */
-		childregs->regs[0] = usp;		/* user fork */
+	p->thread.reg0 = (unsigned long) childregs;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread->reg12 = usp;
+		p->thread->reg13 = arg;
+		p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
 	} else {
-		childregs->regs[28] = (unsigned long) ti; /* kernel fork */
-		childregs->regs[0] = (unsigned long) childregs;
+		*childregs = *current_pt_regs();
+		childregs->regs[7] = 0;		/* Clear error flag */
+		childregs->regs[4] = 0;		/* Child gets zero as return value */
+		if (usp)
+			childregs->regs[0] = usp;	/* user fork */
+		p->thread.reg3 = (unsigned long) ret_from_fork;
 	}
 
-	p->thread.reg0 = (unsigned long) childregs;
-	p->thread.reg3 = (unsigned long) ret_from_fork;
 	p->thread.cp0_psr = 0;
 
 	return 0;
@@ -120,32 +119,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
 	return 1;
 }
 
-static void __noreturn
-kernel_thread_helper(void *unused0, int (*fn)(void *),
-		 void *arg, void *unused1)
-{
-	do_exit(fn(arg));
-}
-
-/*
- * Create a kernel thread.
- */
-long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.regs[6] = (unsigned long) arg;
-	regs.regs[5] = (unsigned long) fn;
-	regs.cp0_epc = (unsigned long) kernel_thread_helper;
-	regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
-			((regs.cp0_psr & 0x3) << 2);
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
-			0, &regs, 0, NULL, NULL);
-}
-
 unsigned long thread_saved_pc(struct task_struct *tsk)
 {
 	return task_pt_regs(tsk)->cp0_epc;
diff --git a/arch/score/kernel/sys_score.c b/arch/score/kernel/sys_score.c
index d45cf00a335..47c20ba4616 100644
--- a/arch/score/kernel/sys_score.c
+++ b/arch/score/kernel/sys_score.c
@@ -48,92 +48,3 @@ sys_mmap(unsigned long addr, unsigned long len, unsigned long prot,
 		return -EINVAL;
 	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 }
-
-asmlinkage long
-score_fork(struct pt_regs *regs)
-{
-	return do_fork(SIGCHLD, regs->regs[0], regs, 0, NULL, NULL);
-}
-
-/*
- * Clone a task - this clones the calling program thread.
- * This is called indirectly via a small wrapper
- */
-asmlinkage long
-score_clone(struct pt_regs *regs)
-{
-	unsigned long clone_flags;
-	unsigned long newsp;
-	int __user *parent_tidptr, *child_tidptr;
-
-	clone_flags = regs->regs[4];
-	newsp = regs->regs[5];
-	if (!newsp)
-		newsp = regs->regs[0];
-	parent_tidptr = (int __user *)regs->regs[6];
-	child_tidptr = (int __user *)regs->regs[8];
-
-	return do_fork(clone_flags, newsp, regs, 0,
-			parent_tidptr, child_tidptr);
-}
-
-asmlinkage long
-score_vfork(struct pt_regs *regs)
-{
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
-			regs->regs[0], regs, 0, NULL, NULL);
-}
-
-/*
- * sys_execve() executes a new program.
- * This is called indirectly via a small wrapper
- */
-asmlinkage long
-score_execve(struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname((char __user*)regs->regs[4]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return error;
-
-	error = do_execve(filename->name,
-			  (const char __user *const __user *)regs->regs[5],
-			  (const char __user *const __user *)regs->regs[6],
-			  regs);
-
-	putname(filename);
-	return error;
-}
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-asmlinkage
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register unsigned long __r4 asm("r4") = (unsigned long) filename;
-	register unsigned long __r5 asm("r5") = (unsigned long) argv;
-	register unsigned long __r6 asm("r6") = (unsigned long) envp;
-	register unsigned long __r7 asm("r7");
-
-	__asm__ __volatile__ ("	\n"
-		"ldi	r27, %5		\n"
-		"syscall		\n"
-		"mv	%0, r4		\n"
-		"mv	%1, r7		\n"
-		: "=&r" (__r4), "=r" (__r7)
-		: "r" (__r4), "r" (__r5), "r" (__r6), "i" (__NR_execve)
-		: "r8", "r9", "r10", "r11", "r22", "r23", "r24", "r25",
-		  "r26", "r27", "memory");
-
-	if (__r7 == 0)
-		return __r4;
-
-	return -__r4;
-}