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xen/extras/mini-os
Jeremy Fitzhardinge b57bd6d273 mini-os: work around ld bug causing stupid CTOR count
I'm seeing pvgrub crashing when running CTORs.  It appears its because
the magic in the linker script is generating junk.  If I get ld to
output a map, I see:

.ctors          0x0000000000097000       0x18
                0x0000000000097000                __CTOR_LIST__ = .
                0x0000000000097000        0x4 LONG 0x25c04
                (((__CTOR_END__ - __CTOR_LIST__) / 0x4) - 0x2)
 *(.ctors)
 .ctors         0x0000000000097004       0x10
                /home/jeremy/hg/xen/unstable/stubdom/mini-os-x86_32-grub/mini-os.o
                0x0000000000097014        0x4 LONG 0x0
                0x0000000000097018                __CTOR_END__ = .


In other words, somehow ((0x97018-0x97000) / 4) - 2 = 0x25c04

The specific crash is that the ctor loop tries to call the NULL
sentinel.  I'm seeing the same with the DTOR list.

Avoid this by terminating the loop with the NULL sentinel, and get rid
of the CTOR count entirely.

From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Keir Fraser <keir@xen.org>
2011-08-19 09:57:42 +01:00
..
2011-05-01 10:11:58 +01:00
2009-10-01 12:28:54 +01:00
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2008-03-19 16:20:44 +00:00
2009-10-01 12:28:54 +01:00

 Minimal OS
 ----------

This shows some of the stuff that any guest OS will have to set up.

This includes:

 * installing a virtual exception table
 * handling virtual exceptions
 * handling asynchronous events
 * enabling/disabling async events
 * parsing start_info struct at start-of-day
 * registering virtual interrupt handlers (for timer interrupts)
 * a simple page and memory allocator
 * minimal libc support
 * minimal Copy-on-Write support
 * network, block, framebuffer support
 * transparent access to FileSystem exports (see tools/fs-back)

- to build it just type make.

- to build it with TCP/IP support, download LWIP 1.3 source code and type

  make LWIPDIR=/path/to/lwip/source

- to build it with much better libc support, see the stubdom/ directory

- to start it do the following in domain0 (assuming xend is running)
  # xm create domain_config

This starts the kernel and prints out a bunch of stuff and then once every
second the system time.

If you have setup a disk in the config file (e.g.
disk = [ 'file:/tmp/foo,hda,r' ] ), it will loop reading it.  If that disk is
writable (e.g. disk = [ 'file:/tmp/foo,hda,w' ] ), it will write data patterns
and re-read them.

If you have setup a network in the config file (e.g. vif = [''] ), it will
print incoming packets.

If you have setup a VFB in the config file (e.g. vfb = ['type=sdl'] ), it will
show a mouse with which you can draw color squares.

If you have compiled it with TCP/IP support, it will run a daytime server on
TCP port 13.