4 files changed, 27 insertions, 36 deletions

diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index 6cade9366364..8c82786da823 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -39,34 +39,21 @@ void flush_thread(void)
 
 void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
 {
+        get_safe_registers(regs->regs.gp, regs->regs.fp);
         PT_REGS_IP(regs) = eip;
         PT_REGS_SP(regs) = esp;
-}
-EXPORT_SYMBOL(start_thread);
-
-static long execve1(const char *file,
-                    const char __user *const __user *argv,
-                    const char __user *const __user *env)
-{
-        long error;
-
-        error = do_execve(file, argv, env, &current->thread.regs);
-        if (error == 0) {
-                task_lock(current);
-                current->ptrace &= ~PT_DTRACE;
+        current->ptrace &= ~PT_DTRACE;
 #ifdef SUBARCH_EXECVE1
-                SUBARCH_EXECVE1(&current->thread.regs.regs);
+        SUBARCH_EXECVE1(regs->regs);
 #endif
-                task_unlock(current);
-        }
-        return error;
 }
+EXPORT_SYMBOL(start_thread);
 
 long um_execve(const char *file, const char __user *const __user *argv, const char __user *const __user *env)
 {
         long err;
 
-        err = execve1(file, argv, env);
+        err = do_execve(file, argv, env, &current->thread.regs);
         if (!err)
                 UML_LONGJMP(current->thread.exec_buf, 1);
         return err;
@@ -81,7 +68,7 @@ long sys_execve(const char __user *file, const char __user *const __user *argv,
         filename = getname(file);
         error = PTR_ERR(filename);
         if (IS_ERR(filename)) goto out;
-        error = execve1(filename, argv, env);
+        error = do_execve(filename, argv, env, &current->thread.regs);
         putname(filename);
  out:
         return error;
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 57fc7028714a..c5f5afa50745 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -181,11 +181,12 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
                 struct pt_regs *regs)
 {
         void (*handler)(void);
+        int kthread = current->flags & PF_KTHREAD;
         int ret = 0;
 
         p->thread = (struct thread_struct) INIT_THREAD;
 
-        if (current->thread.forking) {
+        if (!kthread) {
                 memcpy(&p->thread.regs.regs, &regs->regs,
                        sizeof(p->thread.regs.regs));
                 PT_REGS_SET_SYSCALL_RETURN(&p->thread.regs, 0);
@@ -195,8 +196,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
                 handler = fork_handler;
 
                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
-        }
-        else {
+        } else {
                 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
                 p->thread.request.u.thread = current->thread.request.u.thread;
                 handler = new_thread_handler;
@@ -204,7 +204,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 
         new_thread(task_stack_page(p), &p->thread.switch_buf, handler);
 
-        if (current->thread.forking) {
+        if (!kthread) {
                 clear_flushed_tls(p);
 
                 /*
diff --git a/arch/um/kernel/signal.c b/arch/um/kernel/signal.c
index 7362d58efc29..cc9c2350e417 100644
--- a/arch/um/kernel/signal.c
+++ b/arch/um/kernel/signal.c
@@ -22,9 +22,13 @@ static void handle_signal(struct pt_regs *regs, unsigned long signr,
                          struct k_sigaction *ka, siginfo_t *info)
 {
         sigset_t *oldset = sigmask_to_save();
+        int singlestep = 0;
         unsigned long sp;
         int err;
 
+        if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
+                singlestep = 1;
+
         /* Did we come from a system call? */
         if (PT_REGS_SYSCALL_NR(regs) >= 0) {
                 /* If so, check system call restarting.. */
@@ -61,7 +65,7 @@ static void handle_signal(struct pt_regs *regs, unsigned long signr,
         if (err)
                 force_sigsegv(signr, current);
         else
-                signal_delivered(signr, info, ka, regs, 0);
+                signal_delivered(signr, info, ka, regs, singlestep);
 }
 
 static int kern_do_signal(struct pt_regs *regs)
diff --git a/arch/um/kernel/syscall.c b/arch/um/kernel/syscall.c
index f958cb876ee3..a4c6d8eee74c 100644
--- a/arch/um/kernel/syscall.c
+++ b/arch/um/kernel/syscall.c
@@ -17,25 +17,25 @@
 
 long sys_fork(void)
 {
-        long ret;
-
-        current->thread.forking = 1;
-        ret = do_fork(SIGCHLD, UPT_SP(&current->thread.regs.regs),
+        return do_fork(SIGCHLD, UPT_SP(&current->thread.regs.regs),
                       &current->thread.regs, 0, NULL, NULL);
-        current->thread.forking = 0;
-        return ret;
 }
 
 long sys_vfork(void)
 {
-        long ret;
-
-        current->thread.forking = 1;
-        ret = do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
+        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
                       UPT_SP(&current->thread.regs.regs),
                       &current->thread.regs, 0, NULL, NULL);
-        current->thread.forking = 0;
-        return ret;
+}
+
+long sys_clone(unsigned long clone_flags, unsigned long newsp,
+               void __user *parent_tid, void __user *child_tid)
+{
+        if (!newsp)
+                newsp = UPT_SP(&current->thread.regs.regs);
+
+        return do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
+                      child_tid);
 }
 
 long old_mmap(unsigned long addr, unsigned long len,