Now that PPC64 has no-execute support, here is a second try to fix the
single step out of line during kprobe execution.  Kprobes on x86_64 already
solved this problem by allocating an executable page and using it as the
scratch area for stepping out of line.  Reuse that.
Signed-off-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is pass 2 of my patch to add pci domain info to an existing ioctl.  This
time I insert the domain between dev_fn and board_id as Willy suggested and
change the var to unsigned short to ease Christoph's concerns.  Although I
thought unsigned int was the correct var type for this.  I also thought it
didn't matter where I inserted it in the structure.
Signed-off-by: NMike Miller <mike.miller@hp.com>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes a PCI ID I got wrong before.  It also adds support for
another new SAS controller due out this summer.  I didn't have a marketing
name prior to my last submission.  Also modifies the copyright date range.
Signed-off-by: NMike Miller <mike.miller@hp.com>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I believe at least for seccomp it's worth to turn off the tsc, not just for
HT but for the L2 cache too.  So it's up to you, either you turn it off
completely (which isn't very nice IMHO) or I recommend to apply this below
patch.

This has been tested successfully on x86-64 against current cogito
repository (i686 compiles so I didn't bother testing ;).  People selling
the cpu through cpushare may appreciate this bit for a peace of mind.

There's no way to get any timing info anymore with this applied
(gettimeofday is forbidden of course).  The seccomp environment is
completely deterministic so it can't be allowed to get timing info, it has
to be deterministic so in the future I can enable a computing mode that
does a parallel computing for each task with server side transparent
checkpointing and verification that the output is the same from all the 2/3
seller computers for each task, without the buyer even noticing (for now
the verification is left to the buyer client side and there's no
checkpointing, since that would require more kernel changes to track the
dirty bits but it'll be easy to extend once the basic mode is finished).

Eliminating a cold-cache read of the cr4 global variable will save one
cacheline during the tlb flush while making the code per-cpu-safe at the
same time.  Thanks to Mikael Pettersson for noticing the tlb flush wasn't
per-cpu-safe.

The global tlb flush can run from irq (IPI calling do_flush_tlb_all) but
it'll be transparent to the switch_to code since the IPI won't make any
change to the cr4 contents from the point of view of the interrupted code
and since it's now all per-cpu stuff, it will not race.  So no need to
disable irqs in switch_to slow path.
Signed-off-by: NAndrea Arcangeli <andrea@cpushare.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch removes CONFIG_PMAC_PBOOK (PowerBook support).  This is now
split into CONFIG_PMAC_MEDIABAY for the actual hotswap bay that some
powerbooks have, CONFIG_PM for power management related code, and just left
out of any CONFIG_* option for some generally useful stuff that can be used
on non-laptops as well.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The Power Management Unit on PowerMacs is very sensitive to timeouts during
async message exchanges.  It uses rather crude protocol based on a shift
register with an interrupt and is almost continuously exchanging messages with
the host CPU on laptops.

This patch adds a routine to the open_pic driver to be able to select a PMU
driver so that it bumps it's interrupt priority to above the normal level.

This will allow PMU interrupts to occur while another interrupt is pending,
and thus reduce the risk of machine beeing abruptly shutdown by the PMU due to
a timeout in PMU communication caused by excessive interrupt latency.  The
problem is very rare, and usually just doesn't happen, but it is still useful
to make things even more robust.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This provides declarations for new requests, descriptors, and bitfields as
defined in the Wireless USB 1.0 spec.  Device support will involve a new
"Wire Adapter" device class, connecting a USB Host to a cluster of wireless
USB devices.  There will be two adapter types:

  * Host Wireless Adapter (HWA):  the downstream link is wireless, which
    connects a wireless USB host to wireless USB devices (not unlike like
    a hub) including to the second type of adapter.

  * Device Wireless Adapter (DWA): the upstream link is wireless, for
    connecting existing USB devices through wired links into the cluser.

All wireless USB devices will need persistent (and secure!) key storage, and
it's probable that Linux -- or device firmware -- will need to be involved
with that to bootstrap the initial secure key exchange.

Some user interface is required in that initial key exchange, and since the
most "hands-off" one is a wired USB link, I suspect wireless operation will
usually not be the only mode for wireless USB devices.  (Plus, devices can
recharge batteries using wired USB...)  All other key exchange protocols need
error prone user interactions, like copying and/or verifying keys.

It'll likely be a while before we have commercial Wireless USB hardware,
much less Linux implementations that know how to use it.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This updates most of the gadget framework to expect SETUP packets use
USB byteorder (matching the annotation in <linux/usb_ch9.h> and usage
in the host side stack):

  - definition in <linux/usb_gadget.h>
  - gadget drivers:  Ethernet/RNDIS, serial/ACM, file_storage, gadgetfs.
  - dummy_hcd

It also includes some other similar changes as suggested by "sparse",
which was used to detect byteorder bugs.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

More omap_udc updates:

  * OMAP 1710 updates
      - new UDC bit for clearing endpoint toggle, affecting CLEAR_HALT
      - new OTG bits affecting wakeup
  * Fix the bug Vladimir noted, that IN-DMA transfer code path kicks in
    for under 1024 bytes (not "up to 1024 bytes")
  * Handle transceiver setup more intelligently
      - use transceiver whenever one's available; this can be handy
        for GPIO based, loopback, or transceiverless configs
      - cleanup correctly after the "unrecognized HMC" case
  * DMA performance tweaks
      - allow burst/pack for memory access
      - use 16 bit DMA access most of the time on TIPB
  * Add workarounds for some DMA errata (not observed "in the wild"):
      - DMA CSAC/CDAC reads returning zero
      - RX/TX DMA config registers bit 12 always reads as zero (TI patch)
  * More "sparse" warnings removed, notably "changing" the SETUP packet
    to return data in USB byteorder (an API change, null effect on OMAP
    except for these warnings).
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch provides an "isp116x-hcd" driver for Philips'
ISP1160/ISP1161 USB host controllers.

The driver:
 - is relatively small, meant for use on embedded platforms.
 - runs usbtests 1-14 without problems for days.
 - has been in use by 6-7 different people on ARM and PPC platforms,
   running a range of devices including USB hubs.
 - supports suspend/resume of both the platform device and the root hub;
   supports remote wakeup of the root hub (but NOT the platform device)
   by USB devices.
 - does NOT support ISO transfers (nobody has asked for them).
 - is PIO-only.
Signed-off-by: NOlav Kongas <ok@artecdesign.ee>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

- Adjust slice values

- Instead of one async queue, one is defined per priority level. This
  prevents kernel threads (such as reiserfs/x and others) that run at
  higher io priority from conflicting with others. Previously, it was a
  coin toss what io prio the async queue got, it was defined by who
  first set up the queue.

- Let a time slice only begin, when the previous slice is completely
  done. Previously we could be somewhat unfair to a new sync slice, if
  the previous slice was async and had several ios queued. This might
  need a little tweaking if throughput suffers a little due to this,
  allowing perhaps an overlap of a single request or so.

- Optimize the calling of kblockd_schedule_work() by doing it only when
  it is strictly necessary (no requests in driver and work left to do).

- Correct sync vs async logic. A 'normal' process can be purely async as
  well, and a flusher can be purely sync as well. Sync or async is now a
  property of the class defined and requests pending. Previously writers
  could be considered sync, when they were really async.

- Get rid of the bit fields in cfqq and crq, use flags instead.

- Various other cleanups and fixes
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This updates the CFQ io scheduler to the new time sliced design (cfq
v3).  It provides full process fairness, while giving excellent
aggregate system throughput even for many competing processes.  It
supports io priorities, either inherited from the cpu nice value or set
directly with the ioprio_get/set syscalls.  The latter closely mimic
set/getpriority.

This import is based on my latest from -mm.
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Patch from Deepak Saxena

Accidently swapped the order of movne and orrne. Bad.
Signed-off-by: NDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Michael Burian

This does not look like an include file for "i386", so use "ARM" instead.
Signed-off-by: NMichael Burian <dynmail1@gassner-waagen.at>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

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

This call allows the dynamic tick support to reprogram the timer
immediately before the CPU idles.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add separate files for the different 8250 ISA-based serial boards.

Looking across all the various architectures, it seems reasonable that
we can key the availability of the configuration options for these
beasts to the bus-related symbols (iow, CONFIG_ISA).  We also standardise
the base baud/uart clock rate for these boards - I'm sure that isn't
architecture specific, but is solely dependent on the crystal fitted
on the board (which should be the same no matter what type of machine
its fitted into.)
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

the prototypes and inlines aren't actually needed, but let's not diverge
from -mm too far.

This is a multi-part message in MIME format.

We're using __be16 in userland visible types, so we
have to include asm/byteorder.h so that works.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for alternate slave selection algorithms to bonding
balance-xor and 802.3ad modes.  Default mode (what we have now: xor of
MAC addresses) is "layer2", new choice is "layer3+4", using IP and port
information for hashing to select peer.

Originally submitted by Jason Gabler for balance-xor mode;
modified by Jay Vosburgh to additionally support 802.3ad mode.  Jason's
original comment is as follows:

The attached patch to the Linux Etherchannel Bonding driver modifies the
driver's "balance-xor" mode as follows:

      - alternate hashing policy support for mode 2
        * Added kernel parameter "xmit_policy" to allow the specification
          of different hashing policies for mode 2.  The original mode 2
          policy is the default, now found in xmit_hash_policy_layer2().
        * Added xmit_hash_policy_layer34()

This patch was inspired by hashing policies implemented by Cisco,
Foundry and IBM, which are explained in
Foundry documentation found at:
http://www.foundrynet.com/services/documentation/sribcg/Trunking.html#112750Signed-off-by: NJason Gabler <jygabler@lbl.gov>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>

Patch from Lennert Buytenhek

Add a mapping for the ixp2400 and ixp2800 msf unit.  The msf is the
ixp2000's 'media and switch fabric' unit, which handles the networking
part of the chip.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

Add a comment to asm/arch-ixp2000/ixp2000-regs.h describing the
ixp2000 virtual memory map layout.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

As the ixdp cpld mappings now live at 0xfe000000, we can push
VMALLOC_END upwards to 0xfb000000, where the first iotable mapping
begins.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Lennert Buytenhek

All ixdp platforms currently have a cpld mapped in at 0xfafff000.
Since this address is not 1M-aligned, a regular page mapping will be
used instead of a section mapping, which opens up the possibility of
triggering ixp2400 erratum #66 as we only do the XCB=101 workaround
thing for section mappings.
There is still a lot of space higher up in the virtual memory map
for 1M mappings, so move the cpld mapping to 0xfe000000 and make it
1M big so that a section mapping will be used for it.
Signed-off-by: NLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

1. Establish a simple API for process freezing defined in linux/include/sched.h:

   frozen(process)		Check for frozen process
   freezing(process)		Check if a process is being frozen
   freeze(process)		Tell a process to freeze (go to refrigerator)
   thaw_process(process)	Restart process
   frozen_process(process)	Process is frozen now

2. Remove all references to PF_FREEZE and PF_FROZEN from all
   kernel sources except sched.h

3. Fix numerous locations where try_to_freeze is manually done by a driver

4. Remove the argument that is no longer necessary from two function calls.

5. Some whitespace cleanup

6. Clear potential race in refrigerator (provides an open window of PF_FREEZE
   cleared before setting PF_FROZEN, recalc_sigpending does not check
   PF_FROZEN).

This patch does not address the problem of freeze_processes() violating the rule
that a task may only modify its own flags by setting PF_FREEZE. This is not clean
in an SMP environment. freeze(process) is therefore not SMP safe!
Signed-off-by: NChristoph Lameter <christoph@lameter.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch contains the following cleanups:
- make needlessly global code static
- remove the following unused global functions:
  - blkdev_scsi_issue_flush_fn
  - __blk_attempt_remerge
- remove the following unused EXPORT_SYMBOL's:
  - blk_phys_contig_segment
  - blk_hw_contig_segment
  - blkdev_scsi_issue_flush_fn
  - __blk_attempt_remerge
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch contains the following possible cleanups:
- make the needlessly global function __nvram_set_checksum static
- #if 0 the unused global function nvram_set_checksum
- remove the EXPORT_SYMBOL's for both functions
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch makes use of ALIGN() to remove duplicate round-up code.
Signed-off-by: NNick Wilson <njw@osdl.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

o Following patch provides purely cosmetic changes and corrects CodingStyle
  guide lines related certain issues like below in kexec related files

  o braces for one line "if" statements, "for" loops,
  o more than 80 column wide lines,
  o No space after "while", "for" and "switch" key words

o Changes:
  o take-2: Removed the extra tab before "case" key words.
  o take-3: Put operator at the end of line and space before "*/"
Signed-off-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Makes kexec_crashdump() take a pt_regs * as an argument.  This allows to
get exact register state at the point of the crash.  If we come from direct
panic assertion NULL will be passed and the current registers saved before
crashdump.

This hooks into two places:
die(): check the conditions under which we will panic when calling
do_exit and go there directly with the pt_regs that caused the fatal
fault.

die_nmi(): If we receive an NMI lockup while in the kernel use the
pt_regs and go directly to crash_kexec(). We're probably nested up badly
at this point so this might be the only chance to escape with proper
information.
Signed-off-by: NAlexander Nyberg <alexn@telia.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

From: "Vivek Goyal" <vgoyal@in.ibm.com>

o Support for /proc/vmcore interface. This interface exports elf core image
  either in ELF32 or ELF64 format, depending on the format in which elf headers
  have been stored by crashed kernel.
o Added support for CONFIG_VMCORE config option.
o Removed the dependency on /proc/kcore.

From: "Eric W. Biederman" <ebiederm@xmission.com>

This patch has been refactored to more closely match the prevailing style in
the affected files.  And to clearly indicate the dependency between
/proc/kcore and proc/vmcore.c

From: Hariprasad Nellitheertha <hari@in.ibm.com>

This patch contains the code that provides an ELF format interface to the
previous kernel's memory post kexec reboot.

Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds support for retrieving the address of elf core header if one
is passed in command line.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.

Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch retrieves the max_pfn being used by previous kernel and stores it
in a safe location (saved_max_pfn) before it is overwritten due to user
defined memory map.  This pfn is used to make sure that user does not try to
read the physical memory beyond saved_max_pfn.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

o Following patch exports kexec global variable "crash_notes" to user space
  through sysfs as kernel attribute in /sys/kernel.
Signed-off-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add kexec support for s390 architecture.

From: Milton Miller <miltonm@bga.com>

- Fix passing of first argument to relocate_kernel assembly.
- Fix Kconfig description.
- Remove wrong comment and comments that describe obvious things.
- Allow only KEXEC_TYPE_DEFAULT as image type -> dump not supported.
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch implements the kexec support for ppc64 platforms.

A couple of notes:

1)  We copy the pages in virtual mode, using the full base kernel
    and a statically allocated stack.   At kexec_prepare time we
    scan the pages and if any overlap our (0, _end[]) range we
    return -ETXTBSY.

    On PowerPC 64 systems running in LPAR (logical partitioning)
    mode, only a small region of memory, referred to as the RMO,
    can be accessed in real mode.  Since Linux runs with only one
    zone of memory in the memory allocator, and it can be orders of
    magnitude more memory than the RMO, looping until we allocate
    pages in the source region is not feasible.  Copying in virtual
    means we don't have to write a hash table generation and call
    hypervisor to insert translations, instead we rely on the pinned
    kernel linear mapping.  The kernel already has move to linked
    location built in, so there is no requirement to load it at 0.

    If we want to load something other than a kernel, then a stub
    can be written to copy a linear chunk in real mode.

2)  The start entry point gets passed parameters from the kernel.
    Slaves are started at a fixed address after copying code from
    the entry point.

    All CPUs get passed their firmware assigned physical id in r3
    (most calling conventions use this register for the first
    argument).

    This is used to distinguish each CPU from all other CPUs.
    Since firmware is not around, there is no other way to obtain
    this information other than to pass it somewhere.

    A single CPU, referred to here as the master and the one executing
    the kexec call, branches to start with the address of start in r4.
    While this can be calculated, we have to load it through a gpr to
    branch to this point so defining the register this is contained
    in is free.  A stack of unspecified size is available at r1
    (also common calling convention).

    All remaining running CPUs are sent to start at absolute address
    0x60 after copying the first 0x100 bytes from start to address 0.
    This convention was chosen because it matches what the kernel
    has been doing itself.  (only gpr3 is defined).

    Note: This is not quite the convention of the kexec bootblock v2
    in the kernel.  A stub has been written to convert between them,
    and we may adjust the kernel in the future to allow this directly
    without any stub.

3)  Destination pages can be placed anywhere, even where they
    would not be accessible in real mode.  This will allow us to
    place ram disks above the RMO if we choose.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NR Sharada <sharada@in.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add code to clear the hash table and invalidate the tlb for native (SMP,
non-LPAR) mode.  Supports 16M and 4k pages.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NR Sharada <sharada@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I have tweaked this patch slightly to handle an empty list
of pages to relocate passed to relocate_new_kernel.  And
I have added ppc_md.machine_crash_shutdown.  To keep up with
the changes in the generic kexec infrastructure.

From: Albert Herranz <albert_herranz@yahoo.es>

The following patch adds support for kexec on the ppc32 platform.

Non-OpenFirmware based platforms are likely to work directly without
additional changes on the kernel side.  The kexec-tools userland package
may need to be slightly updated, though.

For OpenFirmware based machines, additional work is still needed on the
kernel side before kexec support is ready.  Benjamin Herrenschmidt is
kindly working on that part.

In order for a ppc platform to use the kexec kernel services it must
implement some ppc_md hooks.  Otherwise, kexec will be explicitly disabled,
as suggested by benh.

There are 3+1 new ppc_md hooks that a platform supporting kexec may
implement.  Two of them are mandatory for kexec to work.  See
include/asm-ppc/machdep.h for details.

- machine_kexec_prepare(image)

  This function is called to make any arrangements to the image before it
  is loaded.

  This hook _MUST_ be provided by a platform in order to activate kexec
  support for that platform.  Otherwise, the platform is considered to not
  support kexec and the kexec_load system call will fail (that makes all
  existing platforms by default non-kexec'able).

- machine_kexec_cleanup(image)

  This function is called to make any cleanups on image after the loaded
  image data it is freed.  This hook is optional.  A platform may or may
  not provide this hook.

- machine_kexec(image)

  This function is called to perform the _actual_ kexec.  This hook
  _MUST_ be provided by a platform in order to activate kexec support for
  that platform.

  If a platform provides machine_kexec_prepare but forgets to provide
  machine_kexec, a kexec will fall back to a reboot.

  A ready-to-use machine_kexec_simple() generic function is provided to,
  hopefully, simplify kexec adoption for embedded platforms.  A platform
  may call this function from its specific machine_kexec hook, like this:

void myplatform_kexec(struct kimage *image)
{
        machine_kexec_simple(image);
}

- machine_shutdown()

  This function is called to perform any machine specific shutdowns, not
  already done by drivers.  This hook is optional.  A platform may or may
  not provide this hook.

An example (trimmed) platform specific module for a platform supporting
kexec through the existing machine_kexec_simple follows:

/* ... */

#ifdef CONFIG_KEXEC
int myplatform_kexec_prepare(struct kimage *image)
{
        /* here, we can place additional preparations
*/
        return 0; /* yes, we support kexec */
}

void myplatform_kexec(struct kimage *image)
{
        machine_kexec_simple(image);
}
#endif /* CONFIG_KEXEC */

/* ... */

void __init
platform_init(unsigned long r3, unsigned long r4,
unsigned long r5,
              unsigned long r6, unsigned long r7)
{

/* ... */

#ifdef CONFIG_KEXEC
        ppc_md.machine_kexec_prepare =
myplatform_kexec_prepare;
        ppc_md.machine_kexec         =
myplatform_kexec;
#endif /* CONFIG_KEXEC */

/* ... */

}

The kexec ppc kernel support has been heavily tested on the GameCube Linux
port, and, as reported in the fastboot mailing list, it has been tested too
on a Moto 82xx ppc by Rick Richardson.
Signed-off-by: NAlbert Herranz <albert_herranz@yahoo.es>
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>