This patch series implements the new signalfd() system call.

I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal().  If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK).  This
seems to be working fine on my Dual Opteron machine.  I made a quick test
program for it:

http://www.xmailserver.org/signafd-test.c

The signalfd() system call implements signal delivery into a file descriptor
receiver.  The signalfd file descriptor if created with the following API:

int signalfd(int ufd, const sigset_t *mask, size_t masksize);

The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea).  Use "ufd" == -1 if you want a brand new
signalfd file.

The "mask" allows to specify the signal mask of signals that we are interested
in.  The "masksize" parameter is the size of "mask".

The signalfd fd supports the poll(2) and read(2) system calls.  The poll(2)
will return POLLIN when signals are available to be dequeued.  As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.

The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer.  The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error.  The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned.  The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.

If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned.  A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process.  The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:

struct signalfd_siginfo {
	__u32 signo;	/* si_signo */
	__s32 err;	/* si_errno */
	__s32 code;	/* si_code */
	__u32 pid;	/* si_pid */
	__u32 uid;	/* si_uid */
	__s32 fd;	/* si_fd */
	__u32 tid;	/* si_fd */
	__u32 band;	/* si_band */
	__u32 overrun;	/* si_overrun */
	__u32 trapno;	/* si_trapno */
	__s32 status;	/* si_status */
	__s32 svint;	/* si_int */
	__u64 svptr;	/* si_ptr */
	__u64 utime;	/* si_utime */
	__u64 stime;	/* si_stime */
	__u64 addr;	/* si_addr */
};

[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch moves the sig_kernel_* and related macros from kernel/signal.c
to linux/signal.h, and cleans them up slightly.  I need the sig_kernel_*
macros for default signal behavior in the utrace code, and want to avoid
duplication or overhead to share the knowledge.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move sighand_cachep definitioni to linux/signal.h

The sighand cache is only used in fs/exec.c and kernel/fork.c.  It is defined
in kernel/fork.c but only used in fs/exec.c.

The sighand_cachep is related to signal processing.  So add the definition to
signal.h.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The recent interrupt rework introduced bit value conflicts with sparc.
Instead of introducing new architecture flags mess, move the interrupt SA_
flags out of the signal namespace and replace them by interrupt related flags.

This allows to remove the obsolete SA_INTERRUPT flag and clean up the bit
field values.

This patch:

Move the interrupt related SA_ flags out of linux/signal.h and rename them to
IRQF_ .  This moves the interrupt related flags out of the signal namespace
and allows to remove the architecture dependencies.

SA_INTERRUPT is not needed by userspace and glibc so it can be removed safely.

The existing SA_ constants are kept for easy transition and will be
removed after a 6 month grace period.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Jody McIntyre <scjody@modernduck.com>
Cc: Ben Collins <bcollins@debian.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Jens Axboe <axboe@suse.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: Andi Kleen <ak@muc.de>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>                                 Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: David Howells <dhowells@redhat.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- Add new SA_PROBEIRQ which suppresses the new sharing-mismatch warning.
  Some drivers like to use request_irq() to find an unused interrupt slot.

- Use it in i82365.c

- Kill unused SA_PROBE.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

__exit_signal() is private to release_task() now.  I think it is better to
make it static in kernel/exit.c and export flush_sigqueue() instead - this
function is much more simple and straightforward.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

While rooting aroung in the signal code trying to understand how to fix the
SIG_IGN ploy (set sig handler to SIG_IGN and flood system with high speed
repeating timers) I came across what, I think, is a problem in sigaction()
in that when processing a SIG_IGN request it flushes signals from 1 to
SIGRTMIN and leaves the rest.  Attempt to fix this.
Signed-off-by: NGeorge Anzinger <george@mvista.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some ARM platforms have the ability to program the interrupt controller to
detect various interrupt edges and/or levels.  For some platforms, this is
critical to setup correctly, particularly those which the setting is dependent
on the device.

Currently, ARM drivers do (eg) the following:

	err = request_irq(irq, ...);

	set_irq_type(irq, IRQT_RISING);

However, if the interrupt has previously been programmed to be level sensitive
(for whatever reason) then this will cause an interrupt storm.

Hence, if we combine set_irq_type() with request_irq(), we can then safely set
the type prior to unmasking the interrupt.  The unfortunate problem is that in
order to support this, these flags need to be visible outside of the ARM
architecture - drivers such as smc91x need these flags and they're
cross-architecture.

Finally, the SA_TRIGGER_* flag passed to request_irq() should reflect the
property that the device would like.  The IRQ controller code should do its
best to select the most appropriate supported mode.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This lock is used in sigqueue_free(), but it is always equal to
current->sighand->siglock, so we don't need to keep it in the struct
sigqueue.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Now m68k no longer sets HAVE_ARCH_GET_SIGNAL_TO_DELIVER, can it be removed
completely? Or may ARM26 still need it? Note that its usage was removed from
kernel/signal.c about 2 months ago.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds a new function valid_signal() that tests if its argument is
a valid signal number.

The reasons for adding this new function are:

- some code currently testing _NSIG directly has off-by-one errors.
  Using this function instead avoids such errors.

- some code currently tests unsigned signal numbers for <0 which is
  pointless and generates warnings when building with gcc -W.  Using this
  function instead avoids such warnings.

I considered various places to add this function but eventually settled on
include/linux/signal.h as the most logical place for it.  If there's some
reason this is a bad choice then please let me know (hints as to a better
location are then welcome of course).
Signed-off-by: NJesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The attached patch moves the IRQ-related SA_xxx flags (namely, SA_PROBE,
SA_SAMPLE_RANDOM and SA_SHIRQ) from all the arch-specific headers to
linux/signal.h.  This looks like a left-over after the irq-handling code
was consolidated.  The code was moved to kernel/irq/*, but the flags are
still left per-arch.

Right now, adding a new IRQ flag to the arch-specific header, like this
patch does:
http://cvs.sourceforge.net/viewcvs.py/*checkout*/alsa/alsa-driver/utils/patches/pcsp-kernel-2.6.10-03.diff?rev=1.1
no longer works, it breaks the compilation for all other arches, unless you
add that flag to all the other arch-specific headers too.  So I think such
a clean-up makes sense.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!