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>

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>

misc sparse annotations
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>

Porting the patch I posted for x86_64 to i386.

http://marc.theaimsgroup.com/?l=linux-kernel&m=114178139610707&w=2

o While using kdump, after a system crash when second kernel boots, timer
  vector gets (0x31) locked and CPU does not see timer interrupts
  travelling from IOAPIC to APIC.  Currently it does not lead to boot
  failure in second kernel as timer interrupts continues to come as ExtInt
  through LAPIC directly, but fixing it is good in case some boards do not
  support the other mode.

o After a system crash, it is not safe to service interrupts any more,
  hence interrupts are disabled.  This leads to pending interrupts at
  LAPIC.  LAPIC sends these interrupts to the CPU during early boot of
  second kernel.  Other pending interrupts are discarded saying unexpected
  trap but timer interrupt is serviced and CPU does not issue an LAPIC EOI
  because it think this interrupt came from i8259 and sends ack to 8259.
  This leads to vector 0x31 locking as LAPIC does not clear respective ISR
  and keeps on waiting for EOI.

o This patch issues extra EOI for the pending interrupts who have ISR set.

o Though today only timer seems to be the special case because in early
  boot it thinks interrupts are coming from i8259 and uses
  mask_and_ack_8259A() as ack handler and does not issue LAPIC EOI.  But
  probably doing it in generic manner for all vectors makes sense.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It's been disabled since v2.1.88
Signed-off-by: NBrian Gerst <bgerst@didntduck.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

find_trylock_page() is an odd interface in that it doesn't take a reference
like the others.  Now that XFS no longer uses it, and its last remaining
caller actually wants an elevated refcount, opencode that callsite and
schedule find_trylock_page() for removal.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix migrate_pages_to() definition.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- chips/sharp.c: make two needlessly global functions static

- move some declarations to a header file where they belong to
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This enables the caller to migrate pages from one address space page
cache to another.  In buzz word marketing, you can do zero-copy file
copies!
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This adds support for the sys_splice system call. Using a pipe as a
transport, it can connect to files or sockets (latter as output only).

From the splice.c comments:

   "splice": joining two ropes together by interweaving their strands.

   This is the "extended pipe" functionality, where a pipe is used as
   an arbitrary in-memory buffer. Think of a pipe as a small kernel
   buffer that you can use to transfer data from one end to the other.

   The traditional unix read/write is extended with a "splice()" operation
   that transfers data buffers to or from a pipe buffer.

   Named by Larry McVoy, original implementation from Linus, extended by
   Jens to support splicing to files and fixing the initial implementation
   bugs.
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Define atomic_sub_and_test to fix build failures.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

As done in asm-generic/local.h in mainline. Otherwise local_t was 32-bit
even on a 64-bit kernel.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

spinlock.c needs _can_lock helpers. Rewrite _is_locked helpers to be
_can_lock helpers.
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Fix up some ISA/EISA stuff.

(Note: isa_ accessors have been removed from asm/io.h)
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Remove CONFIG_DEBUG_IOREMAP, it's now obsolete and won't work anyway.
Remove it from lib/KConfig since it was only available on parisc.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Enable CONFIG_HPPA_IOREMAP by default and remove all now unnecessary code.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Instead of making it a #define in asm/io.h, allow user to select
to turn on IOREMAP from the config menu.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Add STRICT_MM_TYPECHECKS to page.h as other architectures do.
Signed-off-by: NHelge Deller <deller@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

We need to do a little renaming of our original syntax because
of the difference in arguments.
Signed-off-by: NJames Bottomley <jejb@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

This should now allow SG_IO and fuse to function correctly on our
platform.
Signed-off-by: NJames Bottomley <jejb@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

pdc_stable.c is explicitly licensed under GPL version 2.
Signed-off-by: NThibaut VARENE <varenet@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>

Add __mca_table to the DISCARD list for the gate.lds linker script to
avoid broken linker references when linking the final vmlinux file.

Also add comment to include/asm-ia64/asmmacros.h to avoid anyone else
hitting this problem in the future.

Credits to James Bottomley <James.Bottomley@SteelEye.com> for spotting
the DISCARD list in gate.lds.S
Signed-off-by: NJes Sorensen <jes@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Add RMPP support for additional management classes that support it.
Also, validate RMPP is consistent with management class specified.
Signed-off-by: NHal Rosenstock <halr@voltaire.com>
Signed-off-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add a field to the host_set called 'flags' (was host_set_flags changed
to suit Jeff)
Add a simplex_claimed field so we can remember who owns the DMA channel
Add a ->mode_filter() hook to allow drivers to filter modes
Add docs for mode_filter and set_mode
Filter according to simplex state
Filter cable in core

This provides the needed framework to support all the mode rules found
in the PATA world. The simplex filter deals with 'to spec' simplex DMA
systems found in older chips. The cable filter avoids duplicating the
same rules in each chip driver with PATA. Finally the mode filter is
neccessary because drive/chip combinations have errata that forbid
certain modes with some drives or types of ATA object.

Drive speed setup remains per channel for now and the filters now use
the framework Tejun put into place which cleans them up a lot from the
older libata-pata patches.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Some hardware doesn't want the usual mode setup logic running. This
allows the hardware driver to replace it for special cases in the least
invasive way possible.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This is the minimal patch set to enable the current code to be used with
a controller following SFF (ie any PATA and early SATA controllers)
safely without crashes if there is no BMDMA area or if BMDMA is not
assigned by the BIOS for some reason.

Simplex status is recorded but not acted upon in this change, this isn't
a problem with the current drivers as none of them are for simplex
hardware. A following diff will deal with that.

The flags in the probe structure remain ->host_set_flags although Jeff
asked me to rename them, simply because the rename would break the usual
Linux rules that old code should break when there are changes. not
compile and run and then blow up/eat your computer/etc. Renaming this
later is a trivial exercise once a better name is chosen.
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Remove oprofile spinlock backtrace code now we have proper calltrace
support. Also make MMCRA sihv and sipr bits a variable since they may
change in future cpus. Finally, MMCRA should be a 64bit quantity.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Add oprofile calltrace support to powerpc. Disable spinlock backtracing
now we can use calltrace info.

(Updated to work on both 32bit and 64bit by me).
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.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>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Fix 44x and BookE page fault handler to correctly lock PTE before
trying to pte_update() it, otherwise this PTE might be swapped out
after pte_present() check but before pte_uptdate() call, resulting in
corrupted PTE. This can happen with enabled preemption and low memory
condition.
Signed-off-by: NEugene Surovegin <ebs@ebshome.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Move 'tsk->sighand = NULL' from cleanup_sighand() to __exit_signal().  This
makes the exit path more understandable and allows us to do
cleanup_sighand() outside of ->siglock protected section.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch kills PIDTYPE_TGID pid_type thus saving one hash table in
kernel/pid.c and speeding up subthreads create/destroy a bit.  It is also a
preparation for the further tref/pids rework.

This patch adds 'struct list_head thread_group' to 'struct task_struct'
instead.

We don't detach group leader from PIDTYPE_PID namespace until another
thread inherits it's ->pid == ->tgid, so we are safe wrt premature
free_pidmap(->tgid) call.

Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID).
Should the need arise, we can use find_task_by_pid()->group_leader.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-By: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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>

Cosmetic, rename __exit_sighand to cleanup_sighand and move it close to
copy_sighand().

This matches copy_signal/cleanup_signal naming, and I think it is easier to
follow.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

__exit_signal() does important cleanups atomically under ->siglock.  It is
also called from copy_process's error path.  This is not good, for example we
can't move __unhash_process() under ->siglock for that reason.

We should not mix these 2 paths, just look at ugly 'if (p->sighand)' under
'bad_fork_cleanup_sighand:' label.  For copy_process() case it is sufficient
to just backout copy_signal(), nothing more.

Again, nobody can see this task yet.  For CLONE_THREAD case we just decrement
signal->count, otherwise nobody can see this ->signal and we can free it
lockless.

This patch assumes it is safe to do exit_thread_group_keys() without
tasklist_lock.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The only caller of exit_sighand(tsk) is copy_process's error path.  We can
call __exit_sighand() directly and kill exit_sighand().

This 'tsk' was not yet registered in pid_hash[] or init_task.tasks, it has no
external references, nobody can see it, and

	IF (clone_flags & CLONE_SIGHAND)
		At least 'current' has a reference to ->sighand, this
		means atomic_dec_and_test(sighand->count) can't be true.

	ELSE
		Nobody can see this ->sighand, this means we can free it
		without any locking.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add lock_task_sighand() helper and converts group_send_sig_info() to use
it.  Hopefully we will have more users soon.

This patch also removes '!sighand->count' and '!p->usage' checks, I think
they both are bogus, racy and unneeded (but probably it makes sense to
restore them as BUG_ON()s).

->sighand is cleared and it's ->count is decremented in release_task() with
sighand->siglock held, so it is a bug to have '!p->usage || !->count' after
we already locked and verified it is the same.  On the other hand, an
already dead task without ->sighand can have a non-zero ->usage due to
ptrace, for example.

If we read the stale value of ->sighand we must see the change after
spin_lock(), because that change was done while holding that same old
->sighand.siglock.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch borrows a clever Hugh's 'struct anon_vma' trick.

Without tasklist_lock held we can't trust task->sighand until we locked it
and re-checked that it is still the same.

But this means we don't need to defer 'kmem_cache_free(sighand)'.  We can
return the memory to slab immediately, all we need is to be sure that
sighand->siglock can't dissapear inside rcu protected section.

To do so we need to initialize ->siglock inside ctor function,
SLAB_DESTROY_BY_RCU does the rest.
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>