Convert special mapping install from nopage to fault.

Because the "vm_file" is NULL for the special mapping, the generic VM
code has messed up "vm_pgoff" thinking that it's an anonymous mapping
and the offset does't matter.  For that reason, we need to undo the
vm_pgoff offset that got added into vmf->pgoff.

[ We _really_ should clean that up - either by making this whole special
  mapping code just use a real file entry rather than that ugly array of
  "struct page" pointers, or by just making the VM code realize that
  even if vm_file is NULL it may not be a regular anonymous mmap.
							 - Linus ]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] Fix large MCA bootmem allocation
  [IA64] Simplify cpu_idle_wait
  [IA64] Synchronize RBS on PTRACE_ATTACH
  [IA64] Synchronize kernel RSE to user-space and back
  [IA64] Rename TIF_PERFMON_WORK back to TIF_NOTIFY_RESUME
  [IA64] Wire up timerfd_{create,settime,gettime} syscalls

Commit 2f569afd ("CONFIG_HIGHPTE vs.
sub-page page tables") caused some build breakage due to pgtable_t only
getting declared in the CONFIG_X86_PAE case.

Move the declaration outside the PAE section.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  IB/core: Remove unused struct ib_device.flags member
  IB/core: Add IP checksum offload support
  IPoIB: Add send gather support
  IPoIB: Add high DMA feature flag
  IB/mlx4: Use multiple WQ blocks to post smaller send WQEs
  mlx4_core: Clean up struct mlx4_buf
  mlx4_core: For 64-bit systems, vmap() kernel queue buffers
  IB/mlx4: Consolidate code to get an entry from a struct mlx4_buf

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/blackfin-2.6: (24 commits)
  [Blackfin] arch: import defines for BF547 -- it is just like the BF548, but no CAN
  [Blackfin] arch: fix build fails only include header files when enabled
  [Blackfin] arch: declare default INSTALL_PATH for Blackfin ports
  [Blackfin] arch: Encourage users to use the spidev character driver: Provide platform support
  [Blackfin] arch: Enable UART2 and UART3 for bf548
  [Blackfin] arch: Enable NET2272 on BF561-EZkit - remove request_mem_region
  [Blackfin] arch:Fix BUG [#3876] pfbutton test for BTN3 on bf533 don't show complete info
  [Blackfin] arch: remove duplicated definitions of the line discipline numbers N_* in asm-blackfin/termios.h
  [Blackfin] arch: fix building with mtd uclinux by putting the mtd_phys option into the function it actually gets used in
  [Blackfin] arch: simpler header and update dates
  [Blackfin] arch: move the init sections to the end of memory
  [Blackfin] arch: change the trace buffer control start/stop logic in the exception handlers
  [Blackfin] arch: fix typo in printk message
  [Blackfin] arch: this is an ezkit, not a stamp, so fixup the init function name
  [Blackfin] arch: add slightly better help text for CPLB_INFO
  [Blackfin] arch: Fix BUG - Enable ISP1362 driver to work ok with BF561
  [Blackfin] arch: Fix header file information
  [Blackfin] arch: Add Support for ISP1362
  [Blackfin] arch: add support for cmdline partitioning to the BF533-STAMP flash map driver and enable it as a module by default
  [Blackfin] arch: hook up set_irq_wake in Blackfin's irq code
  ...

Thanks to Kay for keeping us honest.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>
Acked-by: NGreg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

x25_asy does not take an ldisc reference before calling the flush method.
Fix it to use the helper function we provide.
Signed-off-by: NAlan Cox <alan@redhat.com>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lib/scatterlist.c is needed by drivers/media/video/videobuf-dma-sg.c, and
we would like to be able to use the latter without PCI too, for example, on
PXA270 ARM CPU.  It is then possible to create a configuration with
CONFIG_BLOCK=n, where only module code will need scatterlist.c.  Therefore
it must be in obj-y.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In file included from /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/xtensa/kernel/syscall.c:39:
include2/asm/unistd.h:681: error: 'sys_timerfd' undeclared here (not in a function)
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Christian Zankel <chris@zankel.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the FRV cmpxchg_local by breaking the following header dependency loop :

linux/kernel.h -> linux/bitops.h -> asm-frv/bitops.h -> asm-frv/atomic.h
  -> asm-frv/system.h ->
  asm-generic/cmpxchg_local.h -> typecheck() defined in linux/kernel.h

and

linux/kernel.h -> linux/bitops.h -> asm-frv/bitops.h -> asm-frv/atomic.h ->
  asm-generic/cmpxchg_local.h -> typecheck() defined in linux/kernel.h

In order to fix this :
- Move the atomic_test_and_ *_mask inlines from asm-frv/atomic.h (why are they
  there at all anyway ? They are not touching atomic_t variables!) to
  asm-frv/bitops.h.

Also fix a build issue with cmpxchg : it does not cast to (unsigned long *)
like other architectures, to deal with it in the cmpxchg_local macro.

FRV builds fine with this patch.

Thanks to Adrian Bunk <bunk@kernel.org> for spotting this bug.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Adrian Bunk <bunk@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert commit c6caeb7c ("proc: fix the
threaded /proc/self"), since Eric says "The patch really is wrong.
There is at least one corner case in procps that cares."

Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Guillaume Chazarain" <guichaz@yahoo.fr>
Cc: "Pavel Emelyanov" <xemul@openvz.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Avoid confusion about what it might mean, since it's never initialized.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add a device capability to show when it can handle checksum offload.
Also add a send flag for inserting checksums and a csum_ok field to
the completion record.
Signed-off-by: NEli Cohen <eli@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

This patch acts as a preparation for using checksum offload for IB
devices capable of inserting/verifying checksum in IP packets.  The
patch does not actaully turn on NETIF_F_SG - we defer that to the
patches adding checksum offload capabilities.

We only add support for send gathers for datagram mode, since existing
HW does not support checksum offload on connected QPs.
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: NEli Cohen <eli@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

All current InfiniBand devices can handle all DMA addresses, and it's
hard to imagine anyone would be silly enough to build a new device
that couldn't.  Therefore, enable the NETIF_F_HIGHDMA feature for IPoIB.

This has no effect for no, but is needed when we enable gather/scatter
support and checksum stateless offloads.
Signed-off-by: NEli Cohen <eli@mellnaox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

ConnectX HCA supports shrinking WQEs, so that a single work request
can be made of multiple units of wqe_shift.  This way, WRs can differ
in size, and do not have to be a power of 2 in size, saving memory and
speeding up send WR posting.  Unfortunately, if we do this then the
wqe_index field in CQEs can't be used to look up the WR ID anymore, so
our implementation does this only if selective signaling is off.

Further, on 32-bit platforms, we can't use vmap() to make the QP
buffer virtually contigious. Thus we have to use constant-sized WRs to
make sure a WR is always fully within a single page-sized chunk.

Finally, we use WRs with the NOP opcode to avoid wrapping around the
queue buffer in the middle of posting a WR, and we set the
NoErrorCompletion bit to avoid getting completions with error for NOP
WRs.  However, NEC is only supported starting with firmware 2.2.232,
so we use constant-sized WRs for older firmware.  And, since MLX QPs
only support SEND, we use constant-sized WRs in this case.

When stamping during NOP posting, do stamping following setting of the
NOP WQE valid bit.
Signed-off-by: NMichael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The MCA code allocates bootmem memory for NR_CPUS, regardless
of how many cpus the system actually has.  This change allocates
memory only for cpus that actually exist.

On my test system with NR_CPUS = 1024, reserved memory was reduced by 130944k.

Before: Memory: 27886976k/28111168k available (8282k code, 242304k reserved, 5928k data, 1792k init)
After:  Memory: 28017920k/28111168k available (8282k code, 111360k reserved, 5928k data, 1792k init)
Signed-off-by: NRuss Anderson <rja@sgi.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

This is just Venki's patch[*] for x86 ported to ia64.

* http://marc.info/?l=linux-kernel&m=120249201318159&w=2Acked-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

When attaching to a stopped process, the RSE must be explicitly
synced to user-space, so the debugger can read the correct values.
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
CC: Roland McGrath <roland@redhat.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

This is base kernel patch for ptrace RSE bug. It's basically a backport
from the utrace RSE patch I sent out several weeks ago. please review.

when a thread is stopped (ptraced), debugger might change thread's user
stack (change memory directly), and we must avoid the RSE stored in
kernel to override user stack (user space's RSE is newer than kernel's
in the case). To workaround the issue, we copy kernel RSE to user RSE
before the task is stopped, so user RSE has updated data.  we then copy
user RSE to kernel after the task is resummed from traced stop and
kernel will use the newer RSE to return to user.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
CC: Roland McGrath <roland@redhat.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Since the RSE synchronization will need a TIF_ flag, but all

work-to-be-done bits are already used, so we have to multiplex
TIF_NOTIFY_RESUME again.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
Signed-off-by: NTony Luck <tony.luck@intel.com>

Add ia64 hooks for the new syscalls that were added in
commit 4d672e7aSigned-off-by: NTony Luck <tony.luck@intel.com>

Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <bryan.wu@analog.com>

* 'cris' of git://www.jni.nu/cris: (158 commits)
  CRIS v32: Remove hwregs/timer_defs.h, it is now architecture specific.
  CRIS v32: Change drivers/i2c.c locking.
  CRIS v32: Rewrite ARTPEC-3 gpio driver to avoid volatiles and general cleanup.
  CRIS: Add new timerfd syscall entries.
  MAINTAINERS: Add my information for the CRIS port.
  CRIS v32: Correct spelling of bandwidth in function name.
  CRIS v32: Clean up nandflash.c for ARTPEC-3 and ETRAX FS.
  CRIS v10: Cleanup of drivers/gpio.c
  CRIS v10: drivers/net/cris/eth_v10.c rename LED defines to CRIS_LED to avoid name clash.
  CRIS: Make io_pwm_set_period members unsigned in etraxgpio.h
  CRIS: Move ETRAX_AXISFLASHMAP to common Kconfig file.
  CRIS: Drop regs parameter from call to profile_tick in kernel/time.c
  CRIS v32: Fix minor formatting issue in mach-a3/io.c
  CRIS v32: Initialize GIO even if we're rambooting in kernel/head.S
  CRIS v32: Remove kernel/arbiter.c, it now exists in machine dependent directory.
  CRIS v32: Minor changes to avoid errors in asm-cris/arch-v32/hwregs/reg_rdwr.h
  CRIS v32: arch-v32/hwregs/intr_vect_defs.h moved to machine dependent directory.
  CRIS v32: Correct offset for TASK_pid in asm-cris/arch-v32/offset.h
  CRIS v32: Move register map header to machine dependent directory.
  CRIS v32: Let compiler know that memory is clobbered after a break op.
  ...

Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <bryan.wu@analog.com>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  Enhanced partition statistics: documentation update
  Enhanced partition statistics: remove old partition statistics
  Enhanced partition statistics: procfs
  Enhanced partition statistics: sysfs
  Enhanced partition statistics: aoe fix
  Enhanced partition statistics: update partition statitics
  Enhanced partition statistics: core statistics
  block: fixup rq_init() a bit

Manually fixed conflict in drivers/block/aoe/aoecmd.c due to statistics
support.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm:
  dlm: add __init and __exit marks to init and exit functions
  dlm: eliminate astparam type casting
  dlm: proper types for asts and basts
  dlm: dlm/user.c input validation fixes
  dlm: fix dlm_dir_lookup() handling of too long names
  dlm: fix overflows when copying from ->m_extra to lvb
  dlm: make find_rsb() fail gracefully when namelen is too large
  dlm: receive_rcom_lock_args() overflow check
  dlm: verify that places expecting rcom_lock have packet long enough
  dlm: validate data in dlm_recover_directory()
  dlm: missing length check in check_config()
  dlm: use proper type for ->ls_recover_buf
  dlm: do not byteswap rcom_config
  dlm: do not byteswap rcom_lock
  dlm: dlm_process_incoming_buffer() fixes
  dlm: use proper C for dlm/requestqueue stuff (and fix alignment bug)

* 'for-2.6.25' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
  [POWERPC] Add arch-specific walk_memory_remove() for 64-bit powerpc
  [POWERPC] Enable hotplug memory remove for 64-bit powerpc
  [POWERPC] Add remove_memory() for 64-bit powerpc
  [POWERPC] Make cell IOMMU fixed mapping printk more useful
  [POWERPC] Fix potential cell IOMMU bug when switching back to default DMA ops
  [POWERPC] Don't enable cell IOMMU fixed mapping if there are no dma-ranges
  [POWERPC] Fix cell IOMMU null pointer explosion on old firmwares
  [POWERPC] spufs: Fix timing dependent false return from spufs_run_spu
  [POWERPC] spufs: No need to have a runnable SPU for libassist update
  [POWERPC] spufs: Update SPU_Status[CISHP] in backing runcntl write
  [POWERPC] spufs: Fix state_mutex leaks
  [POWERPC] Disable G5 NAP mode during SMU commands on U3

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  [SPARC64]: Make use of the new fs/compat_binfmt_elf.c
  [SPARC64]: Make use of compat_sys_ptrace()

Manually fixed trivial delete/modift conflict in arch/sparc64/kernel/binfmt_elf32.c

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (21 commits)
  [IPSEC] flow: reorder "struct flow_cache_entry" and remove SLAB_HWCACHE_ALIGN
  [DECNET] ROUTE: remove unecessary alignment
  [IPSEC]: Add support for aes-ctr.
  [ISDN]: fix section mismatch warning in enpci_card_msg
  [TIPC]: declare proto_ops structures as 'const'.
  [TIPC]: Kill unused static inline (x5)
  [TC]: oops in em_meta
  [IPV6] Minor cleanup: remove unused definitions in net/ip6_fib.h
  [IPV6] Minor clenup: remove two unused definitions in net/ip6_route.h
  [AF_IUCV]: defensive programming of iucv_callback_txdone
  [AF_IUCV]: broken send_skb_q results in endless loop
  [IUCV]: wrong irq-disabling locking at module load time
  [CAN]: Minor clean-ups
  [CAN]: Move proto_{,un}register() out of spin-locked region
  [CAN]: Clean up module auto loading
  [IPSEC] flow: Remove an unnecessary ____cacheline_aligned
  [IPV4]: route: fix crash ip_route_input
  [NETFILTER]: xt_iprange: add missing #include
  [NETFILTER]: xt_iprange: fix typo in address family
  [NETFILTER]: nf_conntrack: fix ct_extend ->move operation
  ...

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
  acer-wmi, tc1100-wmi: select ACPI_WMI
  ACPI: WMI: Improve Kconfig description
  ACPI: DMI: add Panasonic CF-52 and Thinpad X61
  ACPI: thermal: syntax, spelling, kernel-doc
  intel_menlo: build on X86 only
  ACPI: build WMI on X86 only
  ACPI: cpufreq: Print _PPC changes via cpufreq debug layer
  ACPI: add newline to printk

vmsplice_to_user() must always check the user pointer and length
with access_ok() before copying. Likewise, for the slow path of
copy_from_user_mmap_sem() we need to check that we may read from
the user region.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
Cc: Wojciech Purczynski <cliph@research.coseinc.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Turn off quotas before filesystem is remounted read only.  Otherwise quota
will try to write to read-only filesystem which does no good...  We could
also just refuse to remount ro when quota is enabled but turning quota off
is consistent with what we do on umount.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some devices - notably dm and md - can change their behaviour in response
to BIO_RW_BARRIER requests.  They might start out accepting such requests
but on reconfiguration, they find out that they cannot any more.

ext3 (and other filesystems) deal with this by always testing if
BIO_RW_BARRIER requests fail with EOPNOTSUPP, and retrying the write
requests without the barrier (probably after waiting for any pending writes
to complete).

However there is a bug in the handling for this for ext3.

When ext3 (jbd actually) decides to submit a BIO_RW_BARRIER request, it
sets the buffer_ordered flag on the buffer head.  If the request completes
successfully, the flag STAYS SET.

Other code might then write the same buffer_head after the device has been
reconfigured to not accept barriers.  This write will then fail, but the
"other code" is not ready to handle EOPNOTSUPP errors and the error will be
treated as fatal.

This can be seen without having to reconfigure a device at exactly the
wrong time by putting:

		if (buffer_ordered(bh))
			printk("OH DEAR, and ordered buffer\n");

in the while loop in "commit phase 5" of journal_commit_transaction.

If it ever prints the "OH DEAR ..." message (as it does sometimes for
me), then that request could (in different circumstances) have failed
with EOPNOTSUPP, but that isn't tested for.

My proposed fix is to clear the buffer_ordered flag after it has been
used, as in the following patch.
Signed-off-by: NNeil Brown <neilb@suse.de>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

do_mount() uses a whopping 616 bytes of stack on x86_64 in 2.6.24-mm1,
largely thanks to gcc inlining the various helper functions.

noinlining these can slim it down a lot; on my box this patch gets it down
to 168, which is mostly the struct nameidata nd; left on the stack.

These functions are called only as do_mount() helpers; none of them should
be in any path that would see a performance benefit from inlining...
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

[ Spotted by Miklos ]

Fix a memory leak in init_new_context.  The struct page ** buffer allocated
for install_special_mapping was never recorded, and thus leaked when the
mm_struct was freed.  Fix it by saving the pointer in mm_context_t and freeing
it in arch_exit_mmap.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

%fs needs to be copied from parent to child during fork.

Tidied up some whitespace while I was here.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* arch/um/os-Linux/mem.c (make_tempfile): Don't deref NULL upon failed malloc.

* arch/um/os-Linux/mem.c (make_tempfile): Handle NULL tempdir.
Don't let a long tempdir (e.g., via TMPDIR) provoke heap corruption.

[ jdike - formatting cleanups, deleted obsolete comment ]
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Style changes under arch/um/os-Linux:
	include trimming
	CodingStyle fixes
	some printks needed severity indicators

make_tempfile turns out not to be used outside of mem.c, so it is now static.
Its declaration in tempfile.h is no longer needed, and tempfile.h itself is no
longer needed.

create_tmp_file was also made static.

checkpatch moans about an EXPORT_SYMBOL in user_syms.c which is part of a
macro definition - this is copying a bit of kernel infrastructure into the
libc side of UML because the kernel headers can't be included there.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is
needed on i386 if UML is to run on hosts with varying VMSPLITs without
recompilation.

TASK_SIZE is now defined in terms of a variable, task_size.  This gets rid of
an include of pgtable.h from processor.h, which can cause include loops.

On i386, task_size is calculated early in boot by probing the address space in
a binary search to figure out where the boundary between usable and non-usable
memory is.  This tries to make sure that a page that is considered to be in
userspace is, or can be made, read-write.  I'm concerned about a system-global
VDSO page in kernel memory being hit and considered to be a userspace page.

On x86_64, task_size is just the old value of CONFIG_TOP_ADDR.

A bunch of config variable are gone now.  CONFIG_TOP_ADDR is directly replaced
by TASK_SIZE.  NEST_LEVEL is gone since the relocation of the stubs makes it
irrelevant.  All the HOST_VMSPLIT stuff is gone.  All references to these in
arch/um/Makefile are also gone.

I noticed and fixed a missing extern in os.h when adding os_get_task_size.

Note: This has been revised to fix the 32-bit UML on 64-bit host bug that
Miklos ran into.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>