linux/arch/sh
Huang Ying 3ab8352137 kexec jump
This patch provides an enhancement to kexec/kdump.  It implements the
following features:

- Backup/restore memory used by the original kernel before/after
  kexec.

- Save/restore CPU state before/after kexec.

The features of this patch can be used as a general method to call program in
physical mode (paging turning off).  This can be used to call BIOS code under
Linux.

kexec-tools needs to be patched to support kexec jump. The patches and
the precompiled kexec can be download from the following URL:

       source: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-src_git_kh10.tar.bz2
       patches: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec-tools-patches_git_kh10.tar.bz2
       binary: http://khibernation.sourceforge.net/download/release_v10/kexec-tools/kexec_git_kh10

Usage example of calling some physical mode code and return:

1. Compile and install patched kernel with following options selected:

CONFIG_X86_32=y
CONFIG_KEXEC=y
CONFIG_PM=y
CONFIG_KEXEC_JUMP=y

2. Build patched kexec-tool or download the pre-built one.

3. Build some physical mode executable named such as "phy_mode"

4. Boot kernel compiled in step 1.

5. Load physical mode executable with /sbin/kexec. The shell command
   line can be as follow:

   /sbin/kexec --load-preserve-context --args-none phy_mode

6. Call physical mode executable with following shell command line:

   /sbin/kexec -e

Implementation point:

To support jumping without reserving memory.  One shadow backup page (source
page) is allocated for each page used by kexeced code image (destination
page).  When do kexec_load, the image of kexeced code is loaded into source
pages, and before executing, the destination pages and the source pages are
swapped, so the contents of destination pages are backupped.  Before jumping
to the kexeced code image and after jumping back to the original kernel, the
destination pages and the source pages are swapped too.

C ABI (calling convention) is used as communication protocol between
kernel and called code.

A flag named KEXEC_PRESERVE_CONTEXT for sys_kexec_load is added to
indicate that the loaded kernel image is used for jumping back.

Now, only the i386 architecture is supported.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:04 -07:00
..
boards Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-07-23 18:24:08 -07:00
boot inflate: refactor inflate malloc code 2008-07-25 10:53:28 -07:00
cchips sh: Kill off more dead symbols. 2008-02-14 14:22:12 +09:00
configs Merge branches 'at91', 'dyntick', 'ep93xx', 'iop', 'ixp', 'misc', 'orion', 'omap-reviewed', 'rpc', 'rtc' and 's3c' into devel 2008-07-10 16:38:50 +01:00
drivers sysdev: Pass the attribute to the low level sysdev show/store function 2008-07-21 21:55:02 -07:00
kernel kexec jump 2008-07-26 12:00:04 -07:00
lib sh: Fix up optimized SH-4 memcpy on big endian. 2008-05-16 14:55:07 +09:00
lib64 sh64: Fix up compile warning in event tracer. 2008-05-08 19:51:37 +09:00
math-emu sh: Fix up the math-emu build. 2007-06-11 15:57:42 +09:00
mm bootmem: replace node_boot_start in struct bootmem_data 2008-07-24 10:47:20 -07:00
oprofile sh: Add -Werror for clean directories. 2007-11-07 11:13:55 +09:00
tools sh: remove the broken SH_MPC1211 support 2008-05-08 19:51:39 +09:00
Kconfig add HAVE_CLK to Kconfig, for driver dependencies 2008-07-24 10:47:13 -07:00
Kconfig.cpu sh: Disable big endian for SH-5. 2008-02-14 14:22:10 +09:00
Kconfig.debug sh: Disable 4KSTACKS on nommu. 2008-06-02 13:48:59 +09:00
Makefile sh: Add -mno-fdpic to default flags. 2008-06-09 16:49:43 +09:00