* 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: Al 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: Al 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: Al 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: Al 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: Al 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: Al Viro <viro@zeniv.linux.org.uk>
This include is no longer needed.
(seems to be a leftover from try_to_freeze())
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Al 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: Al 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: Al 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: Al 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: Al 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: Al 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: Al 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: Al 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: Al Viro <viro@zeniv.linux.org.uk>
The tricky part here is that task_pt_regs() on m68k works *only* for
process inside do_signal(). However, we need something much simpler -
pt_regs of a process inside do_signal() may be at different offsets
from the stack bottom, depending on the way we'd entered the kernel,
but for a task inside sys_execve() it *is* at constant offset.
Moreover, for a kernel thread about to become a userland process the
same location is also fine - setting sp to that will leave the kernel
stack pointer at the very bottom of the kernel stack when we finally
switch to userland.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The stack frame "format" field needs to be explicitly set on thread creation
on ColdFire. For a normal long word aligned user stack pointer the frame
format is 0x4.
We were doing this for non-MMU ColdFire, but not for the case with MMU enabled.
So fix it so we always do it if targeting ColdFire.
The old code happend to rely on the stack frame format being inhereted from
the process calling exec. Furture changes means that may not always work,
so we really do want to set it explicitly.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
