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

Pull generic execve() changes from Al Viro:
 "This introduces the generic kernel_thread() and kernel_execve()
  functions, and switches x86, arm, alpha, um and s390 over to them."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
  s390: convert to generic kernel_execve()
  s390: switch to generic kernel_thread()
  s390: fold kernel_thread_helper() into ret_from_fork()
  s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
  um: switch to generic kernel_thread()
  x86, um/x86: switch to generic sys_execve and kernel_execve
  x86: split ret_from_fork
  alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  alpha: switch to generic kernel_thread()
  alpha: switch to generic sys_execve()
  arm: get rid of execve wrapper, switch to generic execve() implementation
  arm: optimized current_pt_regs()
  arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
  generic sys_execve()
  generic kernel_execve()
  new helper: current_pt_regs()
  preparation for generic kernel_thread()
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  ...

include/linux/binfmts.h

@@ -19,6 +19,8 @@ struct pt_regs;
 
 #ifdef __KERNEL__
 #include <linux/sched.h>
+#include <linux/unistd.h>
+#include <asm/exec.h>
 
 #define CORENAME_MAX_SIZE 128
 
@@ -135,5 +137,9 @@ extern void install_exec_creds(struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern void free_bprm(struct linux_binprm *);
 
+#ifdef __ARCH_WANT_KERNEL_EXECVE
+extern void ret_from_kernel_execve(struct pt_regs *normal) __noreturn;
+#endif
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_BINFMTS_H */

include/linux/compat.h

@@ -284,8 +284,12 @@ asmlinkage ssize_t compat_sys_pwritev(unsigned long fd,
 		const struct compat_iovec __user *vec,
 		unsigned long vlen, u32 pos_low, u32 pos_high);
 
-int compat_do_execve(char *filename, compat_uptr_t __user *argv,
-		     compat_uptr_t __user *envp, struct pt_regs *regs);
+int compat_do_execve(const char *filename, const compat_uptr_t __user *argv,
+		     const compat_uptr_t __user *envp, struct pt_regs *regs);
+#ifdef __ARCH_WANT_SYS_EXECVE
+asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr_t __user *argv,
+		     const compat_uptr_t __user *envp);
+#endif
 
 asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
 		compat_ulong_t __user *outp, compat_ulong_t __user *exp,

include/linux/ptrace.h

@@ -401,6 +401,10 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
 #define arch_ptrace_stop(code, info)		do { } while (0)
 #endif
 
+#ifndef current_pt_regs
+#define current_pt_regs() task_pt_regs(current)
+#endif
+
 extern int task_current_syscall(struct task_struct *target, long *callno,
 				unsigned long args[6], unsigned int maxargs,
 				unsigned long *sp, unsigned long *pc);

include/linux/sched.h

@@ -2332,6 +2332,9 @@ extern int do_execve(const char *,
 		     const char __user * const __user *, struct pt_regs *);
 extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
+#ifdef CONFIG_GENERIC_KERNEL_THREAD
+extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
+#endif
 
 extern void set_task_comm(struct task_struct *tsk, char *from);
 extern char *get_task_comm(char *to, struct task_struct *tsk);