From: Alexander Graf <agraf@suse.de>

For OBS, we're running a full cross-guest inside of a VM. When a build
is done there, we reboot the guest as shutdown mechanism.

Unfortunately, reboot is not implemented in linux-user. So this mechanism
fails, spilling unpretty warnings. This patch implements sys_reboot()
emulation.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 linux-user/syscall.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

Index: qemu-0.14.1/linux-user/syscall.c
===================================================================
--- qemu-0.14.1.orig/linux-user/syscall.c
+++ qemu-0.14.1/linux-user/syscall.c
@@ -239,6 +239,8 @@ _syscall6(int,sys_futex,int *,uaddr,int,
           const struct timespec *,timeout,int *,uaddr2,int,val3)
 #endif
 #endif
+_syscall4(int, reboot, int, magic1, int, magic2, unsigned int, cmd,
+          void *, arg);
 
 static bitmask_transtbl fcntl_flags_tbl[] = {
   { TARGET_O_ACCMODE,   TARGET_O_WRONLY,    O_ACCMODE,   O_WRONLY,    },
@@ -5536,7 +5538,11 @@ abi_long do_syscall(void *cpu_env, int n
         break;
 #endif
     case TARGET_NR_reboot:
-        goto unimplemented;
+        if (!(p = lock_user_string(arg4)))
+            goto efault;
+        ret = reboot(arg1, arg2, arg3, p);
+        unlock_user(p, arg4, 0);
+        break;
 #ifdef TARGET_NR_readdir
     case TARGET_NR_readdir:
         goto unimplemented;