Subject: Boot flags in the kernel.

From: Alex deVries <[email-masked]>
Date: Mon, 26 Jan 1998 01:05:14 -0500 (EST)

I'm not sure if what I'm trying to do is possible. I'm trying to implement
the same rootflags that are passwd within the kernel image in i386 into
the MIPS kernel. 

In i386 there's a portion of the boot image reserved for these flags;
they're things like console type, initial filesystem, initial ramdisk
location, etc.  

It's traditionally been more important to have this feature in i386
because there wasn't anything nice like the PROMs on MIPS or Sparcs.

But, there _is a good reason to have it; for install or rescue images it's
nice to be able to boot with compressed initial ramdisk within the same
boot image without having to pass the ramdisk offset on command line
manually.

Where in the kernel would we put this data?

- Alex

-- 
      Alex deVries          Run Linux on everything,
  System Administrator      run everything on Linux.
   The EngSoc Project       Send spam to [email-masked].

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From: "William J. Earl" <[email-masked]>
Date: Mon, 26 Jan 1998 09:36:43 -0800

> Where in the kernel would we put this data?

       I am sure where you should put it, but bear in mind that the
command line options and environment are passed to the kernel much as
if it were a user main program (as argc, argv, and envp, in $a0, $a1,
and $a2), by sash or the PROM.  You can get things like the console
variable that way (console=g means textport and console=d means
serial console).

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From: [email-masked]
Date: Mon, 26 Jan 1998 23:47:14 +0100

> Where in the kernel would we put this data?

If you _really_ need that you can copy the data into the .data segment
during the initialization.  See arch/mips/kernel/setup.c.

  Ralf

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From: Alex deVries <[email-masked]>
Date: Mon, 26 Jan 1998 18:49:57 -0500 (EST)

> during the initialization.  See arch/mips/kernel/setup.c.

But where would I copy it from? Where in the image would the symbols go?

Would I just put this in after kernel_entry and kernel_end are written in
mkboot.c (around lines 620-640)?

- A

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From: [email-masked]
Date: Tue, 27 Jan 1998 01:08:04 +0100

On Mon, Jan 26, 1998 at 06:49:57PM -0500, Alex deVries wrote:

> But where would I copy it from?

Thinking about it, actually it's _way_ more elegant to write just a couple
of lines brewing the right argument line to pass to the kernel and to
just pass it than patching the command line in the kernel binary ...

Where in the image would the symbols go?

No symbols needed.

> mkboot.c (around lines 620-640)?

Mkboot isn't being used on SGI boxes because sash can directly boot the
ELF image produced by the kernel.

  Ralf