arm64: Use generic kernel_thread() implementation

This patch enables CONFIG_GENERIC_KERNEL_THREAD on arm64, changes
copy_threads to cope with kernel threads creation and adapts
ret_from_fork accordingly. The arm64-specific kernel_thread
implementation is no longer needed.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index a6f3f7da6880..08db8972ebcc 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -611,7 +611,10 @@ ENDPROC(ret_to_user)
  */
 ENTRY(ret_from_fork)
         bl      schedule_tail
-        get_thread_info tsk
+        cbz     x19, 1f                         // not a kernel thread
+        mov     x0, x20
+        blr     x19
+1:      get_thread_info tsk
         b       ret_to_user
 ENDPROC(ret_from_fork)