Add the foundations of a new LEDs subsystem.  This patch adds a class which
presents LED devices within sysfs and allows their brightness to be
controlled.
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The LED class/subsystem takes John Lenz's work and extends and alters it to
give what I think should be a fairly universal LED implementation.

The series consists of several logical units:

* LED Core + Class implementation
* LED Trigger Core implementation
* LED timer trigger (example of a complex trigger)
* LED device drivers for corgi, spitz and tosa Zaurus models
* LED device driver for locomo LEDs
* LED device driver for ARM ixp4xx LEDs
* Zaurus charging LED trigger
* IDE disk activity LED trigger
* NAND MTD activity LED trigger

Why?
====

LEDs are really simple devices usually amounting to a GPIO that can be turned
on and off so why do we need all this code?  On handheld or embedded devices
they're an important part of an often limited user interface.  Both users and
developers want to be able to control and configure what the LED does and the
number of different things they'd potentially want the LED to show is large.

A subsystem is needed to try and provide all this different functionality in
an architecture independent, simple but complete, generic and scalable manner.

The alternative is for everyone to implement just what they need hidden away
in different corners of the kernel source tree and to provide an inconsistent
interface to userspace.

Other Implementations
=====================

I'm aware of the existing arm led implementation.  Currently the new subsystem
and the arm code can coexist quite happily.  Its up to the arm community to
decide whether this new interface is acceptable to them.  As far as I can see,
the new interface can do everything the existing arm implementation can with
the advantage that the new code is architecture independent and much more
generic, configurable and scalable.

I'm prepared to make the conversion to the LED subsystem (or assist with it)
if appropriate.

Implementation Details
======================

I've stripped a lot of code out of John's original LED class.  Colours were
removed as LED colour is now part of the device name.  Multiple colours are to
be handled as multiple led devices.  This means you get full control over each
colour.  I also removed the LED hardware timer code as the generic timer isn't
going to add much overhead and is just as useful.  I also decided to have the
LED core track the current LED status (to ease suspend/resume handling)
removing the need for brightness_get implementations in the LED drivers.

An underlying design philosophy is simplicity.  The aim is to keep a small
amount of code giving as much functionality as possible.

The major new idea is the led "trigger".  A trigger is a source of led events.
 Triggers can either be simple or complex.  A simple trigger isn't
configurable and is designed to slot into existing subsystems with minimal
additional code.  Examples are the ide-disk, nand-disk and zaurus-charging
triggers.  With leds disabled, the code optimises away.  Examples are
nand-disk and ide-disk.

Complex triggers whilst available to all LEDs have LED specific parameters and
work on a per LED basis.  The timer trigger is an example.

You can change triggers in a similar manner to the way an IO scheduler is
chosen (via /sys/class/leds/somedevice/trigger).

So far there are only a handful of examples but it should easy to add further
LED triggers without too much interference into other subsystems.

Known Issues
============

The LED Trigger core cannot be a module as the simple trigger functions would
cause nightmare dependency issues.  I see this as a minor issue compared to
the benefits the simple trigger functionality brings.  The rest of the LED
subsystem can be modular.

Some leds can be programmed to flash in hardware.  As this isn't a generic LED
device property, I think this should be exported as a device specific sysfs
attribute rather than part of the class if this functionality is required (eg.
 to keep the led flashing whilst the device is suspended).

Future Development
==================

At the moment, a trigger can't be created specifically for a single LED.
There are a number of cases where a trigger might only be mappable to a
particular LED.  The addition of triggers provided by the LED driver should
cover this option and be possible to add without breaking the current
interface.

A CPU activity trigger similar to that found in the arm led implementation
should be trivial to add.

This patch:

Add some brief documentation of the design decisions behind the LED class and
how it appears to users.
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

One of the LEDs driver files wants to use this.

Probably drivers/mtd/maps/ipaq-flash.c wants to convert as well - right now
it'll be tainting the kernel.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Bowler <jbowler@acm.org>
Cc: "'Richard Purdie'" <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add TIOCL_GETKMSGREDIRECT needed by the userland suspend tool to get the
current value of kmsg_redirect from the kernel so that it can save it and
restore it after resume.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@suse.cz>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix a few memory leaks in drivers/isdn/sc/ioctl.c::sc_ioctl()
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NKarsten Keil <kkeil@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Delete two useless kmalloc wrappers and use kmalloc/kzalloc.  Some weird
NULL checks are also simplified.
Signed-off-by: NTobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

sys_flock() currently has a race which can result in a double free in the
multi-thread case.

Thread 1			Thread 2

sys_flock(file, LOCK_EX)
				sys_flock(file, LOCK_UN)

If Thread 2 removes the lock from inode->i_lock before Thread 1 tests for
list_empty(&lock->fl_link) at the end of sys_flock, then both threads will
end up calling locks_free_lock for the same lock.

Fix is to make flock_lock_file() do the same as posix_lock_file(), namely
to make a copy of the request, so that the caller can always free the lock.

This also has the side-effect of fixing up a reference problem in the
lockd handling of flock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

IN_DELETE events are no longer generated for the removal of a file from a
watched directory.

This seems to be a result of clearing DCACHE_INOTIFY_PARENT_WATCHED in
d_delete() directly before calling fsnotify_nameremove().

Assuming the flag doesn't need to be cleared before dentry_iput(), this
should do the trick.
Signed-off-by: NAmy Griffis <amy.griffis@hp.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Acked-by: NRobert Love <rml@novell.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Since these names on old MSDOS is used as device, so, current fat driver
doesn't allow a user to create those names.  But many OSes and even Windows
can create those names actually, now.

This patch removes the reserved name check.
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix memory migration so that it works regardless of what cpuset the invoking
task is in.

If a task invoked a memory migration, by doing one of:

       1) writing a different nodemask to a cpuset 'mems' file, or

       2) writing a tasks pid to a different cpuset's 'tasks' file,
          where the cpuset had its 'memory_migrate' option turned on, then the
          allocation of the new pages for the migrated task(s) was constrained
          by the invoking tasks cpuset.

If this task wasn't in a cpuset that allowed the requested memory nodes, the
memory migration would happen to some other nodes that were in that invoking
tasks cpuset.  This was usually surprising and puzzling behaviour: Why didn't
the pages move?  Why did the pages move -there-?

To fix this, temporarilly change the invoking tasks 'mems_allowed' task_struct
field to the nodes the migrating tasks is moving to, so that new pages can be
allocated there.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix unsafe reference to a tasks mm struct, by moving the reference inside of a
convenient nearby properly guarded code block.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix cpuset comment involving case of a tasks cpuset pointer being NULL.
Thanks to "the_top_cpuset_hack", this code no longer sees NULL task->cpuset
pointers.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

local_t's were defined to be unsigned.  This increases confusion because
atomic_t's are signed.  The patch goes through and changes all implementations
to use signed longs throughout.

Also, x86-64 was using 32-bit quantities for the value passed into local_add()
and local_sub().  Fixed.

All (actually, both) existing users have been audited.

(Also s/__inline__/inline/ in x86_64/local.h)

Cc: Andi Kleen <ak@muc.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The "3c59x: use mii_check_media" patch introduced a netif_carrier_off in
vortex_up.  10base2 stoped working because of this.  This is removed.

Tx/Rx reset is back in vortex_up because the 3c900B-Combo stops working after
changing from half duplex to full duplex when Tx/Rx reset is done with
vortex_timer.

Also brought back some mii stuff to be sure that it does not break something
else.

Thanks to Pete Clements <clem@clem.clem-digital.net> for reporting and testing.
Signed-off-by: NSteffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The pre-2.6.16 patch "3c59x collision statistics fix" accidentally caused
vortex_error() to not run iowrite16(TxEnable, ioaddr + EL3_CMD) if we got a
maxCollisions interrupt but MAX_COLLISION_RESET is not set.

Thanks to Pete Clements <clem@clem.clem-digital.net> for reporting and testing.
Acked-by: NSteffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The help text says that if you select CONFIG_LBD, then it will automatically
select CONFIG_LFS.  That isn't currently the case, so update the text.

- Get rid of the cruft in the help text mentioning CONFIG_LBD

- Tell unsure users to select CONFIG_LFS.

- Remove the `default n'.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I noticed a bug on the process accounting facility.  In multi-threading
process, some data would be recorded incorrectly when the group_leader dies
earlier than one or more threads.  The attached patch fixes this problem.

See below.  'bugacct' is a test program that create a worker thread after 4
seconds sleeping, then the group_leader dies soon.  The worker thread
consume CPU/Memory for 6 seconds, then exit.  We can estimate 10 seconds as
etime and 6 seconds as stime + utime.  This is a sample program which the
group_leader dies earlier than other threads.

The results of same binary execution on different kernel are below.
-- accounted records --------------------
         |   btime  | utime | stime | etime | minflt | majflt |   comm  |
original | 13:16:40 |  0.00 |  0.00 |  6.10 |    171 |      0 | bugacct |
 patched | 13:20:21 |  5.83 |  0.18 | 10.03 |  32776 |      0 | bugacct |
(*) bugacct allocates 128MB memory, thus 128MB / 4KB = 32768 of minflt is
    appropriate.

-- Test results in original kernel ------
$ date; time -p ./bugacct
Tue Mar 28 13:16:36 JST 2006  <- But pacct said btime is 13:16:40
real 10.11                    <- But pacct said etime is 6.10
user 5.96                     <- But pacct said utime is 0.00
sys 0.14                      <- But pacct said stime is 0.00
$
-- Test results in patched kernel -------
$ date; time -p ./bugacct
Tue Mar 28 13:20:21 JST 2006
real 10.04
user 5.83
sys 0.19
$

In the original 2.6.16 kernel, pacct records btime, utime, stime, etime and
minflt incorrectly.  In my opinion, this problem is caused by an assumption
that group_leader dies last.

The following section calculates process running time for etime and btime.
But it means running time of the thread that dies last, not process.  The
start_time of the first thread in the process (group_leader) should be
reduced from uptime to calculate etime and btime correctly.

   ---- do_acct_process() in kernel/acct.c:
   /* calculate run_time in nsec*/
   do_posix_clock_monotonic_gettime(&uptime);
   run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec;
   run_time -= (u64)current->start_time.tv_sec*NSEC_PER_SEC
                                   + current->start_time.tv_nsec;
   ----

The following section calculates stime and utime of the process.
But it might count the utime and stime of the group_leader duplicatly
and ignore the utime and stime of the thread dies last, when one or
more threads remain after group_leader dead.
The ac_utime should be calculated as the sum of the signal->utime
and utime of the thread dies last. The ac_stime should be done also.

   ---- do_acct_process() in kernel/acct.c:
   jiffies = cputime_to_jiffies(cputime_add(current->group_leader->utime,
                                            current->signal->utime));
   ac.ac_utime = encode_comp_t(jiffies_to_AHZ(jiffies));
   jiffies = cputime_to_jiffies(cputime_add(current->group_leader->stime,
                                            current->signal->stime));
   ac.ac_stime = encode_comp_t(jiffies_to_AHZ(jiffies));
   ----

The part of the minflt/majflt calculation has same problem.
This patch solves those problems, I think.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove the recently-added LINUX_FADV_ASYNC_WRITE and LINUX_FADV_WRITE_WAIT
fadvise() additions, do it in a new sys_sync_file_range() syscall instead.
Reasons:

- It's more flexible.  Things which would require two or three syscalls with
  fadvise() can be done in a single syscall.

- Using fadvise() in this manner is something not covered by POSIX.

The patch wires up the syscall for x86.

The sycall is implemented in the new fs/sync.c.  The intention is that we can
move sys_fsync(), sys_fdatasync() and perhaps sys_sync() into there later.

Documentation for the syscall is in fs/sync.c.

A test app (sync_file_range.c) is in
http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz.

The available-to-GPL-modules do_sync_file_range() is for knfsd: "A COMMIT can
say NFS_DATA_SYNC or NFS_FILE_SYNC.  I can skip the ->fsync call for
NFS_DATA_SYNC which is hopefully the more common."

Note: the `async' writeout mode SYNC_FILE_RANGE_WRITE will turn synchronous if
the queue is congested.  This is trivial to fix: add a new flag bit, set
wbc->nonblocking.  But I'm not sure that we want to expose implementation
details down to that level.

Note: it's notable that we can sync an fd which wasn't opened for writing.
Same with fsync() and fdatasync()).

Note: the code takes some care to handle attempts to sync file contents
outside the 16TB offset on 32-bit machines.  It makes such attempts appear to
succeed, for best 32-bit/64-bit compatibility.  Perhaps it should make such
requests fail...

Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Convert the remaining semaphores to mutexes in the IPMI driver.  The
watchdog was using a semaphore as a real semaphore (for IPC), so the
conversion there required adding a completion.
Signed-off-by: NCorey Minyard <minyard@acm.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Tidy up various coding standard things, mostly removing the space after !,
but also break some long lines and fix a few other spacing inconsistencies.
Also fixes some bad error reporting when deleting an IPMI user.
Signed-off-by: NCorey Minyard <minyard@acm.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Matt Domsch noticed a startup race with the IPMI kernel thread, it was
possible (though extraordinarly unlikely) that a message could come in
before the upper layer was ready to handle it.  This patch splits the
startup processing of an IPMI interface into two parts, one to get ready
and one to actually start the processes to receive messages from the
interface.

[akpm@osdl.org: cleanups]
Signed-off-by: NCorey Minyard <minyard@acm.org>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Alan sayeth "Based on Linus original comments about _GPL we should export
tty_insert_flip_char as EXPORT_SYMBOL because it used to be EXPORT_SYMBOL
equivalent (trivial inline).  The other features are new extensions are were
not available to drivers before so need not be provided except as _GPL
functionality as far as I can see."

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=6294

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Philippe Vouters <Philippe.Vouters@laposte.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

EDAC_752X uses pci_scan_single_device(), which is only available if
CONFIG_HOTPLUG is enabled, so limit this driver with HOTPLUG.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Cc: Dave Peterson <dsp@llnl.gov>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The boot cmdline is parsed in parse_early_param() and
parse_args(,unknown_bootoption).

And __setup() is used in obsolete_checksetup().

	start_kernel()
		-> parse_args()
			-> unknown_bootoption()
				-> obsolete_checksetup()

If __setup()'s callback (->setup_func()) returns 1 in
obsolete_checksetup(), obsolete_checksetup() thinks a parameter was
handled.

If ->setup_func() returns 0, obsolete_checksetup() tries other
->setup_func().  If all ->setup_func() that matched a parameter returns 0,
a parameter is seted to argv_init[].

Then, when runing /sbin/init or init=app, argv_init[] is passed to the app.
If the app doesn't ignore those arguments, it will warning and exit.

This patch fixes a wrong usage of it, however fixes obvious one only.
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make baby-simple the code for /proc/devices.  Based on the proven design
for /proc/interrupts.

This also fixes the early-termination regression 2.6.16 introduced, as
demonstrated by:

    # dd if=/proc/devices bs=1
    Character devices:
      1 mem
    27+0 records in
    27+0 records out

This should also work (but is untested) when /proc/devices >4096 bytes,
which I believe is what the original 2.6.16 rewrite fixed.

[akpm@osdl.org: cleanups, simplifications]
Signed-off-by: NJoe Korty <joe.korty@ccur.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Since base and new_base are of the same type now, we can save one 'if'
branch and simplify the code a bit.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Commit a4a6198b:
	[PATCH] tvec_bases too large for per-cpu data

introduced "struct tvec_t_base_s boot_tvec_bases" which is visible at
compile time.  This means we can kill __init_timer_base and move
timer_base_s's content into tvec_t_base_s.
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>

Don't panic!  Just BUG_ON().
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Mark unwind info for signal trampolines using the new S augmentation flag
introduced in: http://gcc.gnu.org/PR26208.

GCC 4.2 (or patched earlier GCC) will be able to special case unwinding
through frames right above signal trampolines.  As the augmentations start
with z flag and S is at the very end of the augmentation string, older GCCs
will just skip the S flag as unknown (that's why an augmentation flag was
chosen over say a new CFA opcode).
Signed-off-by: NJakub Jelinek <jakub@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

for_each_cpu() actually iterates across all possible CPUs.  We've had mistakes
in the past where people were using for_each_cpu() where they should have been
iterating across only online or present CPUs.  This is inefficient and
possibly buggy.

We're renaming for_each_cpu() to for_each_possible_cpu() to avoid this in the
future.

This patch replaces for_each_cpu with for_each_possible_cpu.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If running on a host not supporting TLS (for instance 2.4) we should report
that cleanly to the user, instead of printing not comprehensible "error 5" for
that.

Additionally, i386 and x86_64 support different ranges for
user_desc->entry_number, and we must account for that; we couldn't pass
ourselves -1 because we need to override previously existing TLS descriptors
which glibc has possibly set, so test at startup the range to use.

x86 and x86_64 existing ranges are hardcoded.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Newly forked threads have no arch_switch_to_skas() called before their first
run, because when schedule() switches to them they're resumed in the body of
thread_wait() inside fork_handler() rather than in switch_threads() in
switch_to_skas().  Compensate this missing call.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Copy the definition of struct user_desc (with another name) for use by
userspace sources (where we use the host headers, and we can't be sure about
their content) to make sure UML compiles.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Implement sys_[gs]et_thread_area and the corresponding ptrace operations for
UML.  This is the main chunk, additional parts follow.  This implementation is
now well tested and has run reliably for some time, and we've understood all
the previously existing problems.

Their implementation saves the new GDT content and then forwards the call to
the host when appropriate, i.e.  immediately when the target process is
running or on context switch otherwise (i.e.  on fork and on ptrace() calls).

In SKAS mode, we must switch registers on each context switch (because SKAS
does not switches tls_array together with current->mm).

Also, added get_cpu() locking; this has been done for SKAS mode, since TT does
not need it (it does not use smp_processor_id()).
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Call arch_switch also in switch_to_skas, even if it's, for now, a no-op for
that case (and mark this in the comment); this will change soon.

Also, arch_switch for TT mode is actually useless when the PT proxy (a
complicate debugging instrumentation for TT mode) is not enabled.  In fact, it
only calls update_debugregs, which checks debugregs_seq against seq (to check
if the registers are up-to-date - seq here means a "version number" of the
registers).

If the ptrace proxy is not enabled, debugregs_seq always stays 0 and
update_debugregs will be a no-op.  So, optimize this out (the compiler can't
do it).

Also, I've been disappointed by the fact that it would make a lot of sense if,
after calling a successful
update_debugregs(current->thread.arch.debugregs_seq),
current->thread.arch.debugregs_seq were updated with the new debugregs_seq.
But this is not done.  Is this a bug or a feature?  For all purposes, it seems
a bug (otherwise the whole mechanism does not make sense, which is also a
possibility to check), which causes some performance only problems (not
correctness), since we write_debugregs when not needed.

Also, as suggested by Jeff, remove a redundant enabling of SIGVTALRM,
comprised in the subsequent local_irq_enable().  I'm just a bit dubious if
ordering matters there...
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ldt-{i386,x86_64}.h is made of two different parts - some code for parsing of
LDT descriptors, which is arch-dependant, and the code to handle uml_ldt_t (an
LDT block inside UML), which is mostly arch-independant (among x86 and x86_64,
at least).

Join the common part in a single file (ldt.h) and split the rest away
(host_ldt-{i386,x86_64}.h).

This is needed because processor.h, with next patches, will start including
the LDT descriptor parsing macros in host_ldt.h, but it can't include ldt.h
because it uses semaphores (and to define semaphores one must first include
processor.h!).
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Comparing this code which is the actual body of the arch-independent
cpu_idle(), it is clear that it's unnecessary to set ->mm and ->active_mm;
beyond that, a kernel thread is not supposed to have ->mm != NULL, only
active_mm.

This showed up because I used the assumption (which is IMHO valid) that kernel
thread have their ->mm == NULL, and it failed for this thread.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

type-safe min() in arch/um/drivers/mconsole_kern.c
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Removed assignments to unused variables in arch/um/os-Linux/Makefile
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

__user annotations (hppfs)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>