I am trying to understand the internals of Xen.
On x86 (and may be other architectures), it appears to me
that xen''s entry point is
void __init __start_xen(multiboot_info_t *mbi)
that lives in xeno-unstable.bk/xen/arch/x86/setup.c.
1. Who builds the structure mbi and calls __start_xen?
2. How is __satrt_xen registered as the entry point?
Is there a place that I can read to understand the transfer
of control from multiboot GRUB to xen''s entry point?
Thanks,
Bharadwaj
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
* Bharadwaj Yadavalli (bharadwaj.yadavalli@hp.com) wrote:> On x86 (and may be other architectures), it appears to me > that xen''s entry point is > > void __init __start_xen(multiboot_info_t *mbi)I believe it is actually ''start'' in arch/x86/boot/x86_32.S, for example. At least, that''s the elf entry point which does low-level setup before calling __start_xen. In there you should find the layout of the multiboot header that grub requires.> that lives in xeno-unstable.bk/xen/arch/x86/setup.c. > > 1. Who builds the structure mbi and calls __start_xen?The boot loader, and then stashes it in specified register (ebx in this case).> 2. How is __satrt_xen registered as the entry point?start is the elf entry point.> Is there a place that I can read to understand the transfer > of control from multiboot GRUB to xen''s entry point?For more info on multiboot, read: http://www.gnu.org/software/grub/manual/multiboot/ thanks, -chris _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, 24 Jun 2005, Bharadwaj Yadavalli wrote:> I am trying to understand the internals of Xen. > > On x86 (and may be other architectures), it appears to me > that xen''s entry point is > > void __init __start_xen(multiboot_info_t *mbi) > > that lives in xeno-unstable.bk/xen/arch/x86/setup.c. > > 1. Who builds the structure mbi and calls __start_xen?See xen/arch/x86/boot/x86_32.S .. __start_xen is called from there, with the multiboot info.. It is at this point that assembler becomes C code, and everything is easier to debug. :)> 2. How is __satrt_xen registered as the entry point?__start_xen is not the "real" entry point; instead it''s the ENTRY(start) line in xen/arch/x86/boot/x86_32.S Carl - -- "There are 10 types of people in the world: Those who understand binary and those that don''t." _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, 2005-06-24 at 14:25 -0400, Bharadwaj Yadavalli wrote:> I am trying to understand the internals of Xen. > > On x86 (and may be other architectures), it appears to me > that xen''s entry point is > > void __init __start_xen(multiboot_info_t *mbi) > > that lives in xeno-unstable.bk/xen/arch/x86/setup.c. > > 1. Who builds the structure mbi and calls __start_xen?The Grub bootloader creates the structure, and calls a Xen startup function defined in xen/arch/x86/boot/x86_32.S . That assembly code does some minimal setup and then calls the C startup function, passing the structure pointer.> 2. How is __satrt_xen registered as the entry point?The Xen image booted by GRUB has a well-specified format which includes the location of the entry point.> Is there a place that I can read to understand the transfer > of control from multiboot GRUB to xen''s entry point?http://www.gnu.org/software/grub/manual/multiboot/multiboot.html - Josh Triplett _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel