e7500 and gas and undefined and ...

[Andrew Dennison]

secondary.inc used to be concatenated into the same file as the definition
of gdt (from entry32.inc). Maybe you just need to wrap gdt in EXT() to show
it's now an external reference to be resolved by the linker? ie:

[andrew at starbug src]$ diff arch/i386/smp/secondary.S.orig
arch/i386/smp/secondary.S
75,76c75,76
<       .word   gdt_end - gdt - 1 /* compute the table limit */
<       .long   gdt                /* we know the offset */
---
>       .word   EXT(gdt_end) - EXT(gdt) - 1 /* compute the table limit */
>       .long   EXT(gdt)                /* we know the offset */

labels like "gdtptr" are already exported in entry32.inc, so this may also
need to be done to "gdt" and "gdt_end" so the linker can resolve the
external references. ie

[andrew at starbug src]$ diff cpu/i386/entry32.inc.orig cpu/i386/entry32.inc
22c22,23
< gdt:
---
> .globl EXT(gdt)
> EXT(gdt):
64c65,66
< gdt_end:
---
> .globl EXT(gdt_end)
> EXT(gdt_end):

I'm still working out the structure of the code so I can look integrating
the SC520 and I haven't compiled these changes so I may be completely off
track...

Andrew

> -----Original Message-----
> From: linuxbios-admin at clustermatic.org
> [mailto:linuxbios-admin at clustermatic.org]On Behalf Of Ronald G Minnich
> Sent: Friday, 18 October 2002 9:04 AM
> To: linuxbios at clustermatic.org
> Subject: e7500 and gas and undefined and ...
>
>
> OK, here is a fun one. secondary.inc moved to separate compilation as
> secondary.S
>
> It won't assemble:
>
> secondary.s: Assembler messages:
> secondary.s:87: Error: subtraction of two symbols in different sections
> `gdt_end' {*UND* section} - `gdt' {*UND* section} at file address 155
> make: *** [secondary.o] Error 1
>
> The problem code is:
> gdtaddr:
>         .word   gdt_end - gdt - 1 /* compute the table limit */
>         .long   gdt                /* we know the offset */
>
> Now, I have to sign off -- kids and all that -- and I'm hoping some of you
> gas experts can puzzle this out. What should happen is that the gdtaddr in
> secondary.S will have pointers to the gdt defined in crt0.S. Obviously
> something needs fixing here so that the undefined references in
> secondary.S are properly set up so you have a gdt in secondary.S. One
> option is to include the gdt from the .inc file.
>
> That *UND* section is kind of suspicious -- Maybe another directive is
> needed?
>
> ron
>
>
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