Re: [PATCH 3/9] x86/entry/32: fix the end of the stack for newly forked tasks

[Josh Poimboeuf]

On Tue, Sep 20, 2016 at 09:10:55PM -0400, Brian Gerst wrote:
> Dropping asmlinkage from schedule_tail() would be a better option if possible.

My understanding is that it's still needed for ia64.  AFAICT, ia64
relies on schedule_tail() having the syscall_linkage function attribute.
>From the gcc manual:

  This attribute is used to modify the IA64 calling convention by
  marking all input registers as live at all function exits. This makes
  it possible to restart a system call after an interrupt without having
  to save/restore the input registers. This also prevents kernel data
  from leaking into application code. 

And the ia64 entry code has some similar language:

		/*
		 * Invoke schedule_tail(task) while preserving in0-in7, which may be needed
		 * in case a system call gets restarted.
		 */
	GLOBAL_ENTRY(ia64_invoke_schedule_tail)
		...

-- 
Josh