Signed-off-by: NAlexey Dobriyan <adobriyan@mail.ru>
Signed-off-by: NDomen Puncer <domen@coderock.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The comment for msleep_interruptible() is wrong, as it will ignore
wait-queue events, but will wake up early for signals.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NDomen Puncer <domen@coderock.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use msleep_interruptible() instead of schedule_timeout() in send_break() to
guarantee the task delays as expected.  Change @duration's units to
milliseconds, and modify arguments in callers appropriately.  Patch is
compile-tested.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NDomen Puncer <domen@coderock.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Not sure why any driver needs to sleep for *two* ticks, so let's fix it.

Use msleep() instead of schedule_timeout() to guarantee the task delays as
expected.  Signals are never checked for by the callers or in the function
itself, so use TASK_UNINTERRUPTIBLE instead of TASK_INTERRUPTIBLE.  The
delay is presumed to have been written when HZ==100, and thus has been
multiplied by 10 to pass to msleep().
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: NDomen Puncer <domen@coderock.org>
Acked-by: NRussell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix a bunch of whitespace oddities and use `unsigned long' for a
jiffies-holding variable.
Signed-off-by: NM.Baris Demiray <baris@labristeknoloji.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

au1100: use C99 struct init.
Signed-off-by: Nrandy_dunlap <rdunlap@xenotime.net>
Acked-by: NRussell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Put function prototypes for memset() and memcpy() ahead of where
there are used, to kill sparse warnings:

arch/x86_64/boot/compressed/../../../../lib/inflate.c:317:3: warning: undefined identifier 'memset'
arch/x86_64/boot/compressed/../../../../lib/inflate.c:601:11: warning: undefined identifier 'memcpy'
arch/x86_64/boot/compressed/misc.c:151:2: warning: undefined identifier 'memcpy'
arch/x86_64/boot/compressed/../../../../lib/inflate.c:317:3: warning: call with no type!
arch/x86_64/boot/compressed/../../../../lib/inflate.c:601:17: warning: call with no type!
arch/x86_64/boot/compressed/misc.c:151:9: warning: call with no type!
Signed-off-by: Nrandy_dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch #if 0's an unused function.
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 contains the following cleanups:
- make some needlessly global functions static
- b1dma.c __init/__exit the functions b1dma_{init,exit}
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I didn't find any possible modular usage of mca_find_device_by_slot in
the kernel, and this patch therefore removes the EXPORT_SYMBOL.

This patch should be safe since mca-legacy is nothing drivers should
move to.
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 contains the following possible cleanups:
- make needlessly global code static
- remove the following unused global function:
  - isdn_audio.c: isdn_audio_2adpcm_flush
- remove the following unused struct:
  - isdn_net.c: isdn_concap_demand_dial_dops
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 contains the following possible cleanups:
- make some needlessly global functions static
- remove the following unused global functions:
  - callbacks.c: cb_out_3
  - capi.c: capi_decode_disc_conf
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 contains the following possible cleanips:
- make some needlessly global code static
- remove the compiled but completely unused debug.c
- remove or #if 0 the following unused global functions:
  - command.c: loopback
  - command.c: loadproc
  - init.c: irq_supported
  - packet.c: print_skb
  - shmem.c: memset_shmem
  - timer.c: trace_timer
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I corrected a small error and enhanced the govenor.txt file with the
ondemand daemon because the kernel configs link to the documentation but
ondemand wasn't documentated.  Feel free to include the patch in the
attachment.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove unneeded fbsysfs printk.
Signed-off-by: NJon Smirl <jonsmirl@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We're accidentally selecting the new fonts by default.  Don't.
Signed-off-by: NJurriaan Kalkman <thunder7@xs4all.nl>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

vesafb will do really silly things like..

mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,4000000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,2000000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,1000000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,800000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,400000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,200000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,100000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,80000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,40000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,20000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,10000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,8000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,4000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,2000 old: write-back new: write-combining
mtrr: type mismatch for e0000000,1000 old: write-back new: write-combining
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x800  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x400  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x200  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x100  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x80  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x40  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x20  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x10  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x8  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x4  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x2  base: 0xe0000000
mtrr: size and base must be multiples of 4 kiB
mtrr: size: 0x1  base: 0xe0000000

Stop scaling down at PAGE_SIZE.
Also fix up some broken indentation.
Signed-off-by: NDave Jones <davej@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
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>

If we are faulting in kernel it is quite possible this will lead to a
panic.  Save trap number, cr2 (in case of page fault) and error_code in the
current thread (these fields already exist for signal delivery but are not
used here).

This helps later kdump crash analyzing from user-space (a script has been
submitted to dig this info out in gdb).
Signed-off-by: NAlexander Nyberg <alexn@telia.com>
Cc: <fastboot@lists.osdl.org>
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>

Add a sysrq-trigger mechanism for kexec based crashdumps.  Alt-Sysrq-c
triggers a kexec based crashdump.
Signed-off-by: NHariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Removed the dependency on backup region.  Now all the information is encoded
in ELF format.  /dev/oldmem is a dummy interface.  User space tool need to be
intelligent enough to parse the elf headers and read the relevant memory areas
with the help of /dev/oldmem.
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>

      Hariprasad Nellitheertha <hari@in.ibm.com>

This patch contains the code that enables us to access the previous kernel's
memory as /dev/oldmem.
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

o Adds support for parsing core ELF32 headers.
o I am expecting ELF32 support to go away down the line. This patch has been
  introduced for testing purposes as gdb can not parse ELF64 headers for
  i386. When a decent user space solution is available, ELF32 support
  can go away.
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>

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>

- config option CONFIG_CRASH_DUMP

- Made it dependent on HIGHMEM.  This is required as capture kernel treats
  the previous kernel's memory as high memmory and stitches a PTE for
  accessing it.
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 Specify "irqpoll" command line option which loading second kernel. This
  helps in reducing driver initialization failures in second kernel due
  to shared interrupts.
o Enabled LAPIC/IOAPIC support for UP kernels in second kernel. This reduces
  the chances of devices sharing the irq and hence reduces the chances of
  driver initialization failures in second kernel.
o Build a UP capture kernel and disabled SMP support.
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 contains the documentation for the kexec based crash dump tool.

Quick kdump-howto
================================================================

1) Download and build kexec-tools.

2) Download and build the latest kexec/kdump (-mm) kernel patchset.
   Two kernels need to be built in order to get this feature working.

  A) First kernel:
   a) Enable "kexec system call" feature:
	CONFIG_KEXEC=y
   b) Physical load address (use default):
	CONFIG_PHYSICAL_START=0x100000
   c) Enable "sysfs file system support":
	CONFIG_SYSFS=y
   d) Boot into first kernel with the command line parameter "crashkernel=Y@X":
      For example: "crashkernel=64M@16M".

  B) Second kernel:
   a) Enable "kernel crash dumps" feature:
	CONFIG_CRASH_DUMP=y
   b) Physical load addreess, use same load address as X in "crashkernel"
      kernel parameter in d) above, e.g., 16 MB or 0x1000000.
	CONFIG_PHYSICAL_START=0x1000000
   c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems).
	CONFIG_PROC_VMCORE=y

3) Boot into the first kernel.

4) Load the second kernel to be booted using:

   kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev>
   maxcpus=1 init 1"

5) System reboots into the second kernel when a panic occurs. A module can be
   written to force the panic, for testing purposes.

6) See Documentation/kdump.txt for how to read the first kernel's
   memory image and how to analyze it.
Signed-off-by: NHariprasad 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: Nrandy_dunlap <rdunlap@xenotime.net>
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>

o Problem: Kexec on panic hangs if first kernel is booted with nmi_watchdog
  command line parameter. This problem occurs because kexec crash shutdown
  code replaces the NMI callback handler. This handler saves the cpu register
  states and halts the cpu. If system is booted with nmi_watchdog parameter,
  then crashing cpu also runs this nmi handler and halts itself.

o This patch fixes the problem by keeping a track of crashing cpu and not
  executing the new nmi handler on crashing cpu.

o There is a dependence on smp_processor_id() function which might return
  insane value for cpu, if cpu field of thread_info is corrupted.
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>

CPU does not save ss and esp on stack if execution was already in kernel mode
at the time of NMI occurrence.  This leads to saving of erractic values for ss
and esp.  This patch fixes the issue.
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>

This is the x86_64 implementation of the crashkernel option.  It reserves
a window of memory very early in the bootup process, so we never use
it for anything but the kernel to switch to when the running
kernel panics.

In addition to reserving this memory a resource structure is registered
so looking at /proc/iomem it is clear what happened to that memory.

ISSUES:
Is it possible to implement this in a architecture generic way?
What should be done with architectures that always use an iommu and
thus don't report their RAM memory resources in /proc/iomem?
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is the x86_64 implementation of machine kexec.  32bit compatibility
support has been implemented, and machine_kexec has been enhanced to not care
about the changing internal kernel paget table structures.

From: Alexander Nyberg <alexn@dsv.su.se>

      build fix
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>