xtensa: switch to generic kernel_thread()

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

1 files changed, 13 insertions, 28 deletions

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 18453067c258..d4ec1381aebc 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1833,34 +1833,6 @@ ENTRY(system_call)
 
 
 /*
- * Create a kernel thread
- *
- * int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
- * a2                    a2                 a3             a4
- */
-
-ENTRY(kernel_thread)
-        entry   a1, 16
-
-        mov     a5, a2                  # preserve fn over syscall
-        mov     a7, a3                  # preserve args over syscall
-
-        movi    a3, _CLONE_VM | _CLONE_UNTRACED
-        movi    a2, __NR_clone
-        or      a6, a4, a3              # arg0: flags
-        mov     a3, a1                  # arg1: sp
-        syscall
-
-        beq     a3, a1, 1f              # branch if parent
-        mov     a6, a7                  # args
-        callx4  a5                      # fn(args)
-
-        movi    a2, __NR_exit
-        syscall                         # return value of fn(args) still in a6
-
-1:      retw
-
-/*
  * Do a system call from kernel instead of calling sys_execve, so we end up
  * with proper pt_regs.
  *
@@ -1958,3 +1930,16 @@ ENTRY(ret_from_fork)
 
         j       common_exception_return
 
+/*
+ * Kernel thread creation helper
+ * On entry, set up by copy_thread: a2 = thread_fn, a3 = thread_fn arg
+ *           left from _switch_to: a6 = prev
+ */
+ENTRY(ret_from_kernel_thread)
+
+        call4   schedule_tail
+        mov     a6, a3
+        callx4  a2
+        call4   do_exit
+
+ENDPROC(ret_from_kernel_thread)