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Problem with gp

To: linux-mips@oss.sgi.com
Subject: Problem with gp
From: Ryan Martindale <ryan@qsicorp.com>
Date: Wed, 31 Jul 2002 11:44:03 -0700
Sender: owner-linux-mips@oss.sgi.com
I seem to be having troubles getting the CVS snapshot up and running.
I've debugged it, and it seems that the problem stems from the fact that
$28 (gp) is modified in the SAVE_SOME macro to point to somewhere on the
stack (not sure why this occurs). Anyways, when I get my first system
timetick interrupt, the update_process_times function fails to get the a
valid task structure pointer and wipes out. Why are we adjusting gp
here, since it is explicitly expected to hold only current_thread_info?

(in stackframe.h)

...
                .macro  SAVE_SOME

...

                sw      $25, PT_R25(sp)
                sw      $28, PT_R28(sp)
                sw      $31, PT_R31(sp)
                ori     $28, sp, 0x1fff
                xori    $28, 0x1fff

...


Ryan


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