Messages in this thread | | | Date | Fri, 04 May 2007 11:55:56 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [RFC PATCH 1/3] Replace paravirt_probe with "platform type" boot header field |
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Eric W. Biederman wrote: > > You should be able to just include linux/screen_info.h instead of duplicating > it inline. >
I'm working on it!!!!!
> I like the use of struct header in the middle of boot_params that > seems like a nice maintenance device, although I'm not quite certain about > > However you haven't documented the old swap_dev field in struct header. > At least rdev still knows about it, so it is probably inappropriate to > merge it with syssize. Not that syssize is actually useful for anything > in a modern system.
Actually, ROM bootloaders care about it, which is why it was expanded out in boot loader protocol 2.04; see the documentation.
> So I just looked at what /sbin/kexec does so we know what to expect. > If I have a bzImage I just grab the first setup_sects (i.e. setup.S) and make > it the initial linux boot parameters, placing the command line immediately > afterwards. > > If I just have a vmlinux so I have to fake it I memset x86_linux_faked_param_header > to zero, before placing in the values I care about. And the size. 4K aka 1 page. > Although I due put the command line at 2K, I think that is actually the historical > kernel usage of the zero page.
Oh flippin' hell. *STABBITY STAB STAB STAB*.
All of which is just evil. So much for "oh, the definition of the zeropage never changes, so it doesn't matter."
> elilo does something similar but starts with a 16K pages and then backs up > 2K for the command line. > > Gujin does something similar but also seems to place a command line at 2K. > > So short of the first 2K we can reasonably expect new parameters to be zero > initialized. Past that we need to be a little more careful.
Oh flippin' hell.
> And 4K seems to be our maximum size for backwards compatibility. Although > we use it in a fairly sparse way, so we should be ok.
Sort of. It's pretty full.
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