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/entry.S b/arch/s390/kernel/entry.S
index 6286985..24de1cd 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -331,14 +331,26 @@
l %r12,__LC_THREAD_INFO
l %r13,__LC_SVC_NEW_PSW+4
tm __PT_PSW+1(%r11),0x01 # forking a kernel thread ?
- jo 0f
- st %r15,__PT_R15(%r11) # store stack pointer for new kthread
-0: l %r1,BASED(.Lschedule_tail)
+ je 1f
+ l %r1,BASED(.Lschedule_tail)
basr %r14,%r1 # call schedule_tail
TRACE_IRQS_ON
ssm __LC_SVC_NEW_PSW # reenable interrupts
j sysc_tracenogo
+1: # it's a kernel thread
+ st %r15,__PT_R15(%r11) # store stack pointer for new kthread
+ l %r1,BASED(.Lschedule_tail)
+ basr %r14,%r1 # call schedule_tail
+ TRACE_IRQS_ON
+ ssm __LC_SVC_NEW_PSW # reenable interrupts
+ lm %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
# at the usual place