Date: Wed, 15 Dec 2004 10:43:45 -0800 From: <Vijay.Singh@nokia.com> To: <hackers@freebsd.org> Subject: loading kernel at any physical address Message-ID: <E40595640FD457418D8F9005C2BEC8496456A2@mvebe001.americas.nokia.com>
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Hello all, for a project I am trying to figure out how to boot a FreeBSD =
kernel loaded at any physical address. Right now the locore.s magic =
works because the load addres (KERNLOAD) and (KERNBASE) are set such =
that
#define R(foo) ((foo)-KERNBASE)
macro is able to get the addresses before paging is enabled.
If the loadaddress information is not embedded in defines, then is the =
following solution expected to work:
.globl _loadaddress /* should be at 16M aligned ??? */
.set _loadaddress,KERNBASE
and then:
NON_GPROF_ENTRY(btext)
nop /* nops for 8 byte alignment */
nop
nop
call 0f
0:
mov 4(%ebp), %eax
add $-8, %eax /* This is actual physical load =
addr */
add $-0x100000, %eax
subl %eax, _loadaddress /* new kernbase w.r.t load addr =
*/
/* instead of standard 1MB reloc =
*/
and then=20
#define R(foo) ((foo)- _loadaddress)
One issue might be loadaddress over 16M, but for this problem we can =
assume that the processor has been in protected mode, so it has access =
to that space.
Any input on this is highly appreciated.
br
vijay
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