Since x86-64 __start_context calls the internal __setcontext:
5089:
00000000000417e0 145 FUNC LOCAL DEFAULT 13 __setcontext
it should call __setcontext directly.
* sysdeps/unix/sysv/linux/x86_64/__start_context.S
(__start_context): Call __setcontext directly.
+2016-03-01 H.J. Lu <hongjiu.lu@intel.com>
+
+ * sysdeps/unix/sysv/linux/x86_64/__start_context.S
+ (__start_context): Call __setcontext directly.
+
2016-02-26 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
testq %rdi, %rdi
je 2f /* If it is zero exit. */
- call JUMPTARGET(__setcontext)
+ call __setcontext
/* If this returns (which can happen if the syscall fails) we'll
exit the program with the return error value (-1). */
movq %rax,%rdi