s390: fold kernel_thread_helper() into ret_from_fork()
... and don't bother with syscall return path in case of kernel
threads.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 1f776f2..39c84e6 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -352,12 +352,22 @@
la %r11,STACK_FRAME_OVERHEAD(%r15)
lg %r12,__LC_THREAD_INFO
tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ?
- jo 0f
- stg %r15,__PT_R15(%r11) # store stack pointer for new kthread
-0: brasl %r14,schedule_tail
+ je 1f
+ brasl %r14,schedule_tail
TRACE_IRQS_ON
ssm __LC_SVC_NEW_PSW # reenable interrupts
j sysc_tracenogo
+1: # it's a kernel thread
+ stg %r15,__PT_R15(%r11) # store stack pointer for new kthread
+ brasl %r14,schedule_tail
+ TRACE_IRQS_ON
+ ssm __LC_SVC_NEW_PSW # reenable interrupts
+ lmg %r9,%r11,__PT_R9(%r11) # load gprs
+ENTRY(kernel_thread_starter)
+ la %r2,0(%r10)
+ basr %r14,%r9
+ la %r2,0
+ br %r11 # do_exit
#
# kernel_execve function needs to deal with pt_regs that is not
