ANNONCE: kexec 2.6.8.1-kexec3

[Eric W. Biederman]

http://www.xmission.com/~ebiederm/files/kexec/2.6.8.1-kexec3/
http://www.xmission.com/~ebiederm/files/kexec/kexec-tools-1.96.tgz

- Current ports now include i386 ppc and x86_64
  Between the three of them I think there are some good examples
  of what is needed to implement kexec.  i386 and ppc can turn
  off their mmu while x86_64 cannot, yet they all implement
  identity mapped memory for code running in the processors
  native mode.

- The code has been reviewed in preparation to sending to Andrew Morton
  and hopefully mainline kernel inclusion.  

- All uses of init_mm have been removed from the generic code

- Three new architecture specific hooks have been added.
  int machine_kexec_prepare(struct kimage *image);
    This does whatever architecture specific setup such
    as allocating page tables that is needed for a given image.

  void machine_kexec_cleanup(struct kimage *image);
    When the image is removed instead of executed this does the
    necessary cleanup.
   
  void machine_shutdown(void);  
    device_shutdown cannot do everything.  There are some pieces
    of hardware that can only be shutdown by architecture specific
    code.  That needed architecture specific shutdown code is
    generally common between machine_restart and machine_kexec,
    and it needs a function to live in.  In addition the 
    coming kexec_on_panic code path needs to do nothing what is
    absolutely necessary, making the architecture specific shutdown
    code inappropriate.

    machine_shutdown is designed to hold the architecture specific
    shutdown code.  

    REBOOT_CMD_KEXEC now calls machine_shutdown just before
    machine_kexec.  Which means the coming kexec_on_panic
    implemenation can skip the unnecessary code by simply
    not calling machine_shutdown.

- The i386 port now no longer uses init_mm and the implemetation
  actually got simpler, and is much more robust in the face
  of changing kernel infrastructure.   Even making it work
  with the 4G/4G patch should be simple.

- The x86_64 port has been tested on both Opterons and Xeons and
  it works fine.  Support for the 32bit x86 system call has not
  been done but I have have a design for it if anyone cares.

- The jointly released port of kexec-tools-1.96 adds support for
  x86_64, fixes a small glitch so it works on even a lowly 386
  (tested) and adds support for linux style arguments to the i386
  bootloader.

And a quick summary of the broken-out patches:

i8259-shutdown.i386.patch
i8259-sysfs.x86_64.patch
   For i386 all I needed to do was add a shutdown the PIC.  
   For x86_64 sysfs support had not even been added for the legacy
   PIC, so I ported the  appropriate code from x86.

apic-virtwire-on-shutdown.i386.patch
apic-virtwire-on-shutdown.x86_64.patch
   The x86 Multiprocessor Specification says the local
   apic needs to be in either pic_mode (i.e. disabled) or
   it needs to be in virtual wire mode.  This patch restores
   the local apic to virtual wirte mode when appropriate.

ioapic-virtwire-on-shutdown.i386.patch
ioapic-virtwire-on-shutdown.x86_64.patch

   The x86 Multiprocessor Specification says access to the
   legacy pic can either be direct to the cpu or it can
   be through a io_apic programed in virtual wire mode.
   This patch examines the ioapic interrupt routing and if an i8259
   is connected to an ioapic in external interrupt mode it places
   the given ioapic in virtual wirte mode instead of disabling
   it completely.

e820-64bit.x86_64.patch
   Someone overzealously copied the resource reservation code
   from x86 and was filter out 64bit io and memory resources. Ouch!
   x86_64 needs this if it is going to allocation 64bit resources
   properly and I need the 64bit memory resources if I want to see
   all of the memory through /proc/iomem.

kexec-generic.patch
   This patch simplys holds the generic part of kexec.

machine_shutdown.x86_64.patch
kexec.x86_64.patch
   The x86_64 port, I simply factor out machine_shutdown from
   machine_restart before I complete the port.

machine_shutdown.i386.patch
kexec.i386.patch
   The i386 port.  While factoring out machine_shutdown I make
   rebooting on the bootstrap cpu the default as required by the
   Multiprocessor Specification and expected by linux.  With
   a number of motherboard specific fixups become unnecessary.

use_mm.patch
kexec.ppc.patch
homebrew-dol-support.ppc.patch [EXPERIMENTAL]
   This is the ppc port.  It still uses init_mm.  So I first
   make use_mm no-static.  The port is not as mature as the x86
   port but it should still work in the majority of cases.  I don't
   think the homebrew Dolphin OS support is clean enough to be
   in the stable kernel but it is included in case people need
   it and as a starting point for something better.

vmlinux-lds.i386.patch [EXPERIMENTAL]
highbzImage.i386.patch [EXPERIMENTAL]
   In the discussions on how to implement kexec_on_panic a key
   question has been can we build a kernel that executes in memory
   the kernel that called panic had reserved.  

   These two patches are my proof of concept that we can make an
   x86 kernel that will execute when loaded at a different memory
   address.  The first patch fixes up vmlinux.lds.S so it vmlinux
   exports the appropriate physical addresses in it's ELF program
   header and adds an option what memory location you want to boot
   from.   This is needed for the kexec_on_panic case if we want
   the panic kernel to load somewhere else.

   The patch makes the bzImage of an i386 kernel built with a
   load_address other than bootable.  This means you don't have
   to use kexec to boot one of these kernels.

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