How does the fallback version get executed? Stepping through the reset sequence it looks from my image that that's the default.
Jordan
At 02:52 PM 11/18/2003, ron minnich wrote:
On Tue, 18 Nov 2003, Jordan Archer wrote:
I'm pretty sure that it's not 32 bit reset code. The problem appears if I try to build an image without a fallback.
oh. When I try to build an image without a fallback (this part is counterintuitive) I always just build a fallback. Possibly that's the wrong thing to do :0)
ron
Jordan Archer jarcher@pobox.com writes:
How does the fallback version get executed? Stepping through the reset sequence
it looks from my image that that's the default.
Possibly a better term would be failsafe image.
What happens is that if everything looks good the fallback image hands control to the normal one. Otherwise it keeps control.
The nice thing is that it is a general purpose technique that can all be done in software.
Eric
* Eric W. Biederman ebiederman@lnxi.com [031119 03:23]:
Possibly a better term would be failsafe image.
What happens is that if everything looks good the fallback image hands control to the normal one. Otherwise it keeps control.
Note: IIRC, the "normal" image is called with protected mode already running, so it needs a different startup code (entry32.s instead of entry16.s?) Also, the failsafe image does not do cmos option handling afair?
Stefan
Stefan Reinauer stepan@suse.de writes:
- Eric W. Biederman ebiederman@lnxi.com [031119 03:23]:
Possibly a better term would be failsafe image.
What happens is that if everything looks good the fallback image hands control to the normal one. Otherwise it keeps control.
Note: IIRC, the "normal" image is called with protected mode already running, so it needs a different startup code (entry32.s instead of entry16.s?)
Yes.
Also, the failsafe image does not do cmos option handling afair?
Correct. That is so the failsafe image will do a known thing.
Right now with etherboot I have been able to keep the two fairly symmetrical. But it is my intention to start sticking a kernel in the flash now that 512KiB byte flash chips and above are getting common. Etherboot was to a large extent about getting something small enough that it could always be used. Once I start sticking a kernel in flash the normal image should start picking up some capabilities not available otherwise.
Right now the big benefit of having the two images is that once you have fallback image working, you can continue development without the need to even remove ROM chips.
Eric
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ebiederman＠lnxi.com -
Jordan Archer -
Stefan Reinauer