Messages in this thread | | | Subject | Re: [PATCH] Use correct x86 reboot vector | From | (Eric W. Biederman) | Date | 11 May 2003 13:12:51 -0600 |
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Davide Libenzi <davidel@xmailserver.org> writes:
> On Sun, 11 May 2003, Eric W. Biederman wrote: > > > The remapping is quite common but it usually happens that after bootup: > > 0xf0000-0xfffff is shadowed RAM. While 0xffff0000-0xffffffff still points > > to the rom chip. > > > > Now if someone could tell me how to do a jump to 0xffff0000:0xfff0 in real > > mode I would find that very interesting. > > Have you ever heard about unreal mode ? But I do not think that a reset > has to start over there. I do not think that exist hw/sw that expect that > reset address to be 0xfffffff0 instead of 0x000ffff0, since they map the > same content.
There is some software at least that knows the difference. I have seen short jumps in a couple of BIOS's. But a reset is very different from a reboot. As memory must be reinitialized etc. So I think going to 0xffff0000:0xfff0 would be a very bad idea if the intent is to get a reliable reboot.
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