* allow kernel_execve() leave the actual return to userland to
caller (selected by CONFIG_GENERIC_KERNEL_EXECVE).  Callers
updated accordingly.
* architecture that does select GENERIC_KERNEL_EXECVE in its
Kconfig should have its ret_from_kernel_thread() do this:
	call schedule_tail
	call the callback left for it by copy_thread(); if it ever
returns, that's because it has just done successful kernel_execve()
	jump to return from syscall
IOW, its only difference from ret_from_fork() is that it does call the
callback.
* such an architecture should also get rid of ret_from_kernel_execve()
and __ARCH_WANT_KERNEL_EXECVE

This is the last part of infrastructure patches in that area - from
that point on work on different architectures can live independently.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Most of them never returned anyway - only two functions had to be
changed.  That allows to simplify their callers a whole lot.

Note that this does *not* apply to kthread_run() callbacks - all of
those had been called from the same kernel_thread() callback, which
did do_exit() already.  This is strictly about very few low-level
kernel_thread() callbacks (there are only 6 of those, mostly as part
of kthread.h and kmod.h exported mechanisms, plus kernel_init()
itself).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The only place where kernel_execve() is called without a way to
return to the caller of kernel_thread() callback is kernel_post().
Reorganize kernel_init()/kernel_post() - instead of the former
calling the latter in the end (and getting freed by it), have the
latter *begin* with calling the former (and turn the latter into
kernel_thread() callback, of course).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

exec_usermodehelper_fns() will do just fine...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and now the asm glue side of that.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It's needed only in setup_sigcontext() and it's always reg - <constant>;
no point passing it all way down through the call chain.  This is just
the signal.c side of that stuff; next will come the asm glue one...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Turn the slow side of work_pending into C function, including all
the looping.  What we get out of that:
	* we do _not_ call get_signal_to_deliver() with IRQs disabled
anymore
	* no need to save/restore volatiles on each pass if there
turns to be more than one (unlikely, but still)
	* all double-restart prevention is in C now.
	* glue gets simpler.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In case we have both NEED_RESCHED and SIGPENDING/NOTIFY_RESUME,
handle the latter first.  We'll get to original priorities in
the next commit, but now that allows to simplify the treatment
of NEED_RESCHED-only case nicely.  Namely, now there no need to
preserve the data for restarts across the call of schedule() in
$work_resched; we can get there only if we had either returned
from syscall without SIGPENDING (in which case we should've
had no restart-worthy return value and want no restarts) or
already got through do_notify_resume() call (in which case we
want no restarts anymore).  So we can just slap 0 into $19
instead of preserving it (and $20).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This include is no longer needed.
(seems to be a leftover from try_to_freeze())
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Tell signal_delivered() to do it instead.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... just tell signal_delivered() to do it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

signal_delivered() will do it in the same case...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

no need to have the call of do_notify_resume() + checks around it
duplicated for vm86 case - a bit of rearranging of ifdefs and we'll
have a perfectly fine copy to jump back to.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we can get into work_pending only if at least one of NEED_RESCHED,
SIGPENDING or NOTIFY_RESUME is set.  So once we'd found no NEED_RESCHED,
there's no need to check that one of the other two is set.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Only the three usual flags (NEED_RESCHED/SIGPENDING/NOTIFY_RESUME)
are looked at in the code checking _TIF_WORK_MASK on that one.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

entry.S code had been looping until no pending signals are left
since 2005 anyway; no need to bother with that in do_signal()
itself.  If the failure to set a sigframe up raises SIGSEGV,
we'll just pick it up the next time around the loop(s) in entry.S
anyway.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Don't bother restoring r28 on syscall restarts; it's clobbered by
syscall anyway.  Reuse (now unused) ->orig_r28 as "no restarts allowed"
flag.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Some architectures had blindly copied it for no reason whatsoever.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Make default just return 0.  The current default (checking
TIF_POLLING_NRFLAG) is taken to architectures that need it;
ones that don't do polling in their idle threads don't need
to defined TIF_POLLING_NRFLAG at all.

ia64 defined both TS_POLLING (used by its tsk_is_polling())
and TIF_POLLING_NRFLAG (not used at all).  Killed the latter...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

never used...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

bits 3..7 in flags are never set there, so this 0xff is pointless
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If it's set, SIGPENDING is also set.  And SIGPENDING is present in
the masks...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

No need to keep 4 copies of that stuff; merged and taken to
entry.S, unused public symbols there killed off.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

too late to do anything there...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we *really* don't want to have restart logics hit when we are returning from
sigreturn() - random replacement of %r4 with -4 just because a signal had
been noticed from timer interrupt that came when %r4 happened to contain
-514 is not nice at all.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

asm glue checks that
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMark Salter <msalter@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>