optimization

The gcc manual says:

|`-fdelete-null-pointer-checks'
|     Use global dataflow analysis to identify and eliminate useless
|     checks for null pointers.  The compiler assumes that dereferencing
|     a null pointer would have halted the program.  If a pointer is
|     checked after it has already been dereferenced, it cannot be null.
|     Enabled at levels `-O2', `-O3', `-Os'.

Now the problem can be seen with this test case:

#include <linux/prefetch.h>
extern void bar(char *x);
void foo(char *x)
{
	prefetch(x);
	if (x)
		bar(x);
}

Because the constraint to the inline asm used in the prefetch() macro is
a memory operand, gcc assumes that the asm code does dereference the
pointer and the delete-null-pointer-checks optimization kicks in.
Inspection of generated assembly for the above example shows that bar()
is indeed called unconditionally without any test on the value of x.

Of course in the prefetch case there is no real dereference and it
cannot be assumed that a null pointer would have been caught at that
point. This causes kernel oopses with constructs like
hlist_for_each_entry() where the list's 'next' content is prefetched
before the pointer is tested against NULL, and only when gcc feels like
applying this optimization which doesn't happen all the time with more
complex code.

It appears that the way to prevent delete-null-pointer-checks
optimization to occur in this case is to make prefetch() into a static
inline function instead of a macro. At least this is what is done on
x86_64 where a similar inline asm memory operand is used (I presume they
would have seen the same problem if it didn't work) and resulting code
for the above example confirms that.

An alternative would consist of replacing the memory operand by a
register operand containing the pointer, and use the addressing mode
explicitly in the asm template. But that would be less optimal than an
offsettable memory reference.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Empty fixup functions are just a waste of code, and are not
necessary.  Remote them.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

HID drivers are in their own directory now, so we have to
include the Kconfig file for arm.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add a clocksource driver for netx systems
Signed-off-by: Luotao Fu <lfu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add a clocksource driver for pxa2xx systems
Signed-off-by: Luotao Fu <lfu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Since we're keeping the ioremap code, we might as well keep it as
close to the standard kernel as possible.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

L_PTE_ASID is not really required to be stored in every PTE, since we
can identify it via the address passed to set_pte_at().  So, create
set_pte_ext() which takes the address of the PTE to set, the Linux
PTE value, and the additional CPU PTE bits which aren't encoded in
the Linux PTE value.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Clean up the KERNEL_RAM_ADDR stuff in arch/arm/kernel/head.S to
make it clearer what's referring to what.  In doing so, remove
the usage of __virt_to_phys(), which is not guaranteed to be
something that the assembler can parse.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Later glibc requires the *at syscalls.  Add them.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Remove the implicit addition of a virtual address
to the UDC registers. This should have been done
by ioremap() in the driver, not by a static map.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

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

Don't set HWCAP_VFP in the processor support file; not only does it
depend on the processor features, but it also depends on the support
code being present.  Therefore, only set it if the support code
detects that we have a VFP coprocessor attached.

Also, move the VFP handling of the coprocessor access register into
the VFP support code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (55 commits)
  ieee1394: sbp2: code formatting around work_struct stuff
  ieee1394: nodemgr: remove a kcalloc
  ieee1394: conditionally export ieee1394_bus_type
  ieee1394: Consolidate driver registering
  ieee1394: sbp2: convert from PCI DMA to generic DMA
  ieee1394: nodemgr: spaces to tabs
  ieee1394: nodemgr: fix deadlock in shutdown
  ieee1394: nodemgr: remove duplicate assignment
  sbp2: make 1bit bitfield unsigned
  ieee1394: schedule *_oui sysfs attributes for removal
  ieee1394: schedule unused symbol exports for removal
  ieee1394: dv1394: schedule for feature removal
  ieee1394: raw1394: defer feature removal of old isoch interface
  ieee1394: ohci1394: call PMac code in shutdown only for proper machines
  ieee1394: ohci1394: reformat PPC_PMAC platform code
  ieee1394: ohci1394: add PPC_PMAC platform code to driver probe
  ieee1394: sbp2: wrap two functions into one
  ieee1394: sbp2: update comment on things to do
  ieee1394: sbp2: use list_move_tail()
  ieee1394: sbp2: more concise names for types and variables
  ...

* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (76 commits)
  [ARM] 4002/1: S3C24XX: leave parent IRQs unmasked
  [ARM] 4001/1: S3C24XX: shorten reboot time
  [ARM] 3983/2: remove unused argument to __bug()
  [ARM] 4000/1: Osiris: add third serial port in
  [ARM] 3999/1: RX3715: suspend to RAM support
  [ARM] 3998/1: VR1000: LED platform devices
  [ARM] 3995/1: iop13xx: add iop13xx support
  [ARM] 3968/1: iop13xx: add iop13xx_defconfig
  [ARM] Update mach-types
  [ARM] Allow gcc to optimise arm_add_memory a little more
  [ARM] 3991/1: i.MX/MX1 high resolution time source
  [ARM] 3990/1: i.MX/MX1 more precise PLL decode
  [ARM] 3986/1: H1940: suspend to RAM support
  [ARM] 3985/1: ixp4xx clocksource cleanup
  [ARM] 3984/1: ixp4xx/nslu2: Fix disk LED numbering (take 2)
  [ARM] 3994/1: ixp23xx: fix handling of pci master aborts
  [ARM] 3981/1: sched_clock for PXA2xx
  [ARM] 3980/1: extend the ARM Versatile sched_clock implementation from 32 to 63 bit
  [ARM] 3979/1: extend the SA11x0 sched_clock implementation from 32 to 63 bit period
  [ARM] 3978/1: macro to provide a 63-bit value from a 32-bit hardware counter
  ...

* 'release' of master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] replace kmalloc+memset with kzalloc
  [IA64] resolve name clash by renaming is_available_memory()
  [IA64] Need export for csum_ipv6_magic
  [IA64] Fix DISCONTIGMEM without VIRTUAL_MEM_MAP
  [PATCH] Add support for type argument in PAL_GET_PSTATE
  [IA64] tidy up return value of ip_fast_csum
  [IA64] implement csum_ipv6_magic for ia64.
  [IA64] More Itanium PAL spec updates
  [IA64] Update processor_info features
  [IA64] Add se bit to Processor State Parameter structure
  [IA64] Add dp bit to cache and bus check structs
  [IA64] SN: Correctly update smp_affinty mask
  [IA64] sparse cleanups
  [IA64] IA64 Kexec/kdump

Merge:
 Atmel AT91RM9200 and AT91SAM9260 changes
 General ARM developments
 Disconfiguous memory cleanups
 64-bit/32-bit division and sched_clock extension patches
 EP93xx support changes
 IOP support changes
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

* 'intx' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/misc-2.6:
  PCI MSI: always toggle legacy-INTx-enable bit upon MSI entry/exit

Do not bother masking/unmasking the parent IRQ
for the mulitplexed EINT irqs, as masking the
leaf seems to be fine.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Cut down the time between requesting a reboot
and actually getting the reboot to happen by
a quarter.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The current code (prior to this change) would disable the PCI INTx
legacy interrupt when enabling MSI... but only on PCI Express.  We
should do this for all MSI devices, for safety's sake.
Signed-off-by: Jeff Garzik <jeff@garzik.org>

It appears that include/asm-arm/bug.h requires include/linux/stddef.h
for the definition of NULL. It seems that stddef.h was always included
indirectly in most cases, and that issue was properly fixed a while ago.

Then commit 5047f09b incorrectly reverted
change from commit ff10952a (bad dwmw2)
and the problem recently resurfaced.

Because the third argument to __bug() is never used anyway, RMK suggested
getting rid of it entirely instead of readding #include <linux/stddef.h>
which this patch does.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Add the mapping for the third S3C2440 serial
port into the default serial devices for the
Osiris.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The RX3715 is similar to the H1940 in the way
that suspend to RAM works, so we can use most
of the extant support for the H1940 with only
a few modifictions
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Support for the GPIO attached LEDs on the VR1000
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Merge is finished, can bring the code in readable style again.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Was I sleepwalking when I wrote this?
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Follow-up to patch "Consolidate driver registering":
Since I plan the lifetime of Linux 2.6.20 to be the deprecation phase
of CONFIG_IEEE1394_EXPORT_FULL_API, it seems fair to keep all previously
exported symbols available with this option until this phase is over.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

This patch consolidates some bookkeeping for driver registering. It
closely models what pci_register_driver() does. The main addition is
that the owner of the driver is set, so we get a proper symlink
for /sys/bus/ieee1394/driver/*/module.

Also moves setting of name and bus type into nodemgr. Because of this,
we can remove the EXPORT_SYMBOL for ieee1394_bus_type, since it's now
only used in ieee1394.ko.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

API conversion without change in functionality
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

whitespace pedantry
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

If "modprobe ohci1394" was quickly followed by "modprobe -r ohci1394",
say with 1 second pause in between, the modprobe -r got stuck in
uninterruptible sleep in kthread_stop.  At the same time the knodemgrd
slept uninterruptibly in bus_rescan_devices_helper.  That's because
driver_detach took the semaphore of the PCI device and
bus_rescan_devices_helper wanted to take the semaphore of the FireWire
host device's parent, which is the same semaphore. This was a regression
since Linux 2.6.16, commit bf74ad5b,
"Hold the device's parent's lock during probe and remove".

The fix (or workaround) adds a dummy driver to the hpsb_host device. Now
bus_rescan_devices_helper won't scan the host device anymore.  This
doesn't hurt since we have no drivers which will bind to these devices
and it is unlikely that there will ever be such a driver.  The dummy
driver is befittingly presented as a representation of ieee1394 itself.

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=6706Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

A signed single-bit bitfield doesn't make much sense. Make it unsigned.
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

There is no manpower available to reform oui.db into a library for use
in more kernel subsystems.  The low ratio of usefulness to size and the
occasional need to update oui.db from IEEE's official list suggest to
drop oui.db.  I plan to make a userspace script available which
translates the remaining numeric sysfs attributes to names of
organizations.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

This also means that former parts of ieee1394's API will be subject to
change or removal.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Known to be affected:
 - libdc1394: prefers video1394 for now, old-style raw1394 support might
   be dropped eventually
 - OpenH323 PWLib, AVC video input module: uses libraw1394's old API
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

There has been an if(...) missing, for ages.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Adjust whitespace and line lengths
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Fixes http://bugzilla.kernel.org/show_bug.cgi?id=7431
iBook G3 threw a machine check exception and put the display backlight
to full brightness after ohci1394 was unloaded and reloaded.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>