The smp_mb() is becaus sync_page() doesn't have PG_locked while it accesses
page_mapping(page).  The comments in the patch (the entire patch is the
addition of this comment) try to explain further how and why smp_mb() is
used.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Always use page counts when doing RLIMIT_MEMLOCK checking to avoid possible
overflow.
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

This is a patch for counting the number of pages for bounce buffers.  It's
shown in /proc/vmstat.

Currently, the number of bounce pages are not counted anywhere.  So, if
there are many bounce pages, it seems that there are leaked pages.  And
it's difficult for a user to imagine the usage of bounce pages.  So, it's
meaningful to show # of bouce pages.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Make the Locking document truer.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Use the new __GFP_NOMEMALLOC to simplify the previous handling of
PF_MEMALLOC.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Mempool is pretty clever.  Looks too clever for its own good :) It
shouldn't really know so much about page reclaim internals.

- don't guess about what effective page reclaim might involve.

- don't randomly flush out all dirty data if some unlikely thing
  happens (alloc returns NULL). page reclaim can (sort of :P) handle
  it.

I think the main motivation is trying to avoid pool->lock at all costs.
However the first allocation is attempted with __GFP_WAIT cleared, so it
will be 'can_try_harder' if it hits the page allocator.  So if allocation
still fails, then we can probably afford to hit the pool->lock - and what's
the alternative?  Try page reclaim and hit zone->lru_lock?

A nice upshot is that we don't need to do any fancy memory barriers or do
(intentionally) racy access to pool-> fields outside the lock.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Mempools have 2 problems.

The first is that mempool_alloc can possibly get stuck in __alloc_pages
when they should opt to fail, and take an element from their reserved pool.

The second is that it will happily eat emergency PF_MEMALLOC reserves
instead of going to their reserved pools.

Fix the first by passing __GFP_NORETRY in the allocation calls in
mempool_alloc.  Fix the second by introducing a __GFP_MEMPOOL flag which
directs the page allocator not to allocate from the reserve pool.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Jack Steiner reported this to have fixed his problem (bad colouring):
"The patches fix both problems that I found - bad
 coloring & excessive pages in pagesets."

In most workloads this is not likely to be such a pronounced problem,
however it should help corner cases.  And avoiding powers of 2 in these
types of memory operations is always a good idea.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

mm/rmap.c:page_referenced_one() and mm/rmap.c:try_to_unmap_one() contain
identical code that

 - takes mm->page_table_lock;

 - drills through page tables;

 - checks that correct pte is reached.

Coalesce this into page_check_address()
Signed-off-by: Nikita Danilov <nikita@clusterfs.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Address bug #4508: there's potential for wraparound in the various places
where we perform RLIMIT_AS checking.

(I'm a bit worried about acct_stack_growth().  Are we sure that vma->vm_mm is
always equal to current->mm?  If not, then we're comparing some other
process's total_vm with the calling process's rlimits).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Anton Altaparmakov <aia21@cam.ac.uk> points out:

- It calls fault_in_pages_readable() which is completely bogus if @nr_segs >
  1.  It needs to be replaced by a to be written
  "fault_in_pages_readable_iovec()".

- It increments @buf even in the iovec case thus @buf can point to random
  memory really quickly (in the iovec case) and then it calls
  fault_in_pages_readable() on this random memory.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Fix a typo.

James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Move definition of NOSTDINC_FLAGS below inclusion of arch Makefile, so
any arch specific settings to $(CC) takes effect before looking up the
compiler include directory.

The previous solution that replaced ':=' with '=' caused gcc to be
invoked one additional time for each directory visited.

This decreases kernel compile time with 0.1 second (3.6 -> 3.5 seconds) when
running make on a fully built kernel
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Tom Rini said:
  Note that there is still a trivial'ish change to make.  When mkimage
  doesn't exist on the host we should say "uImage not made" or
  something similar.

So I did like Tom asked.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Removing the dependency on vmlinux for the install target raised a few
complaints, so instead a new target i added: kernel_install.

kernel_install will install the kernel just like the ordinary install target.
The only difference is that install has a dependency on vmlinux,
kernel_install does not. Therefore kernel_install is the best choice
when accessing the kernel over a NFS mount or as another user.

kernel_install is similar to modules_install in the fact that neither does
a full kernel compile before performing the install.
In this way they are good for root use. Also added back the
dependency on vmlinux for the install target so peoples scripts are no
longer broken.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The documentation on these values seems to be rather wrong.
These values have been determined by mere trial and error.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>

Signed-off-by: Russell King <rmk@arm.linux.org.uk>

Signed-off-by: Russell King <rmk@arm.linux.org.uk>

Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

For older servers which do not support Unicode

Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

When the kernel creates a signal frame on the user stack, it puts the
old stack pointer value at the beginning so that the signal frame is
linked into the chain of stack frames like any other frame.
Unfortunately, for 32-bit processes we are writing the old stack
pointer as a 64-bit value rather than a 32-bit value, and the process
sees that as a null pointer, since it only looks at the first 32 bits,
which are zero since ppc is bigendian and the stack pointer is below
4GB.  This bug is in SLES9 and RHEL4 too, hence the ccs.

This patch fixes the bug by making the signal code write the old stack
pointer as a u32 instead of an unsigned long.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Add the PXA I2C platform device.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>

Allow RTC drivers to return error codes from their read_time
or read_alarm methods.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>

Patch from Sascha Hauer

This patch adds UCFR_RFDIV setting into i.MX serial driver.
This is required, if loader does not fully agree with Linux kernel
about UART setup manner. Linux only blindly expected some values until
now. This should enable to use even serial ports not recognized by
boot-loader as for example third UART found in the bluethoot module.
Patch also enables to detect original setup baudrate in more cases.

Signed-off-by: Pavel Pisa
Signed-off-by: Sascha Hauer
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

The IXDP2800 is an evalution platform for the IXP2800 processor that
has two IXP2800s connected to the same PCI bus.  This is problematic
as both CPUs will try to configure the PCI bus as they boot linux.
Contrary to on the other IXP2000 platforms, the boot loader on the
IXDP2800 doesn't configure the PCI bus properly, so we do want the
linux instance on one of the CPUs to do that.
Making one of the CPUs ignore the PCI bus (and thus act like a pure
PCI slave device) is not an option because there is a 82559 NIC on
the PCI bus for each of the CPUs.
The chosen solution is to have the master CPU configure the PCI bus
while the slave is kept in a quiescent state, and then to have the
slave CPU scan the PCI bus (without assigning resources) while the
master is kept in a quiescent state.  After this ritual, the master
deletes the slave NIC from its PCI device list, the slave deletes
the master NIC from its device list, and (almost) all is well.
There's still one little problem: each of the CPUs has a 1G SDRAM
BAR, but the IXP2000 only has 512M of outbound PCI memory window.
We solve this by hand-assigning the master and slave SDRAM BARs to
a location outside each of the IXP's outbound PCI windows, and by
having the rest of the BARs autoconfigured in the outbound PCI
windows, in the range [e0000000..ffffffff], so that there is a 1:1
pci:phys mapping between them.
Even with this patch, a number of issues still remain -- just imagine
what happens if one of the CPUs is rebooted, by watchdog or by hand,
but the other one isn't.  But those issues are not easily fixable
given the strange PCI layout of this board and the behavior of the
boot loader shipped with the platform.

Signed-off-by: Lennert Buytenhek
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from George G. Davis

This patch is required for kernel XIP support on ARMv6 machines.  It ensures that the access permission bits for kernel XIP section descriptors are APX=1 and AP[1:0]=01, which is Kernel read-only/User no access permissions.  Prior to this change, kernel XIP section descriptor access permissions were set to Kernel no access/User no access on ARMv6 machines and the kernel would therefore hang upon entry to userspace when set_fs(USER_DS) was executed.

Signed-off-by: Steve Longerbeam
Signed-off-by: George G. Davis
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Olav Kongas

On ARM, the outX() and writeX() families of macros take the
result of cpu_to_leYY(), which is of restricted type __leYY,
and feed it to __raw_writeX(), which expect an argument of
unrestricted type. This results in 'sparse -Wbitwise'
warnings about incorrect types in assignments. Analogous
type mismatch warnings are issued for inX() and readX()
counterparts. The below patch resolves these warnings by
adding forced typecasts.

Signed-off-by: Olav Kongas
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

This patch entirely reworks the kernel assistance for NPTL on ARM.
In particular this provides an efficient way to retrieve the TLS
value and perform atomic operations without any instruction emulation
nor special system call.  This even allows for pre ARMv6 binaries to
be forward compatible with SMP systems without any penalty.
The problematic and performance critical operations are performed
through segment of kernel provided user code reachable from user space
at a fixed address in kernel memory.  Those fixed entry points are
within the vector page so we basically get it for free as no extra
memory page is required and nothing else may be mapped at that
location anyway.
This is different from (but doesn't preclude) a full blown VDSO
implementation, however a VDSO would prevent some assembly tricks with
constants that allows for efficient branching to those code segments.
And since those code segments only use a few cycles before returning to
user code, the overhead of a VDSO far call would add a significant
overhead to such minimalistic operations.
The ARM_NR_set_tls syscall also changed number.  This is done for two
reasons:
1) this patch changes the way the TLS value was previously meant to be
   retrieved, therefore we ensure whatever library using the old way
   gets fixed (they only exist in private tree at the moment since the
   NPTL work is still progressing).
2) the previous number was allocated in a range causing an undefined
   instruction trap on kernels not supporting that syscall and it was
   determined that allocating it in a range returning -ENOSYS would be
   much nicer for libraries trying to determine if the feature is
   present or not.

Signed-off-by: Nicolas Pitre
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from George G. Davis

As noted in http://www.arm.com/linux/patch-2.6.9-arm1.gz, the "Faulty SWP instruction on 1136 doesn't set bit 11 in DFSR." So the v6_early_abort handler does not report the correct rd/wr direction for the SWP instruction which may result in SEGVS or hangs. In order to work around this problem, this patch merely updates the fix contained in the ARM Ltd. patch to use the macroised abort handler fixups.

Signed-off-by: George G. Davis
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

Assigning the address zero to a PCI device BAR causes some part of the
PCI subsystem to believe that resource allocation for that BAR failed
due to resource conflicts, which will make attempts to enable the
device fail.  Work around this by assigning I/O addresses starting
from 00010000.
While we're at it, make the PCI I/O resource end at 0001ffff, since we
only have 64k of outbound I/O window on the IXP2000, and we don't do
bank switching.

Signed-off-by: Lennert Buytenhek
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

On the IXDP2800, the bootloader does an awful job of configuring
the PCI bus, so we make linux reconfigure everything.  Having a 1:1
pci:phys address mapping generally simplifies everything, so try to
allocate PCI addresses from the [e0000000..ffffffff] range, which is
the physical address range of the outbound PCI window on the IXP2000.
This does not affect any of the other IXP2000 platforms since they
all use their bootloader's PCI resource assignment.

Signed-off-by: Lennert Buytenhek
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

Export ixp2000_pci_config_addr, to be used by the IXDP2800 platform
setup code to coordinate booting the master and slave NPU.

Signed-off-by: Lennert Buytenhek
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

This makes a trap on the 'iret' that returns us to user space
cause a nice clean SIGSEGV, instead of just a hard (and silent)
exit.

That way a debugger can actually try to see what happened, and
we also properly notify everybody who might be interested about
us being gone.

This loses the error code, but tells the debugger what happened
with ILL_BADSTK in the siginfo.

It's old sanity checking that may have been useful for debugging, but
is just bogus these days.

Noticed by Mattia Belletti.

In order to properly fix some issues with cpufreq vs. sleep on
PowerBooks, I had to add a suspend callback to the pmac_cpufreq driver.
I must force a switch to full speed before sleep and I switch back to
previous speed on resume.

I also added a driver flag to disable the warnings in suspend/resume
since it is expected in this case to have different speed (and I want it
to fixup the jiffies properly).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The addition of the PT_NOTE didn't take in the x86_64 version of the i386
vDSO, because I forgot the linker script bit in that copy.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>