i386: Fix null interrupt handler (ignore_int) message ?

From: Ahmed S. Darwish
Date: Mon Sep 24 2007 - 18:08:38 EST

Hi all,

I'm getting little confused by some ignore_int (null interrupt handler) code in
head.S. Code notifies the user about the unknown raised interrupt by below

.asciz "Unknown interrupt or fault at EIP %p %p %p\n"

and prints it using below code path:

pushl %eax; pushl %ecx; pushl %edx; pushl %es; pushl %ds
pushl 16(%esp); pushl 24(%esp);
pushl 32(%esp); pushl 40(%esp);
pushl $int_msg
call printk

** But here's the state of stack before calling printk:

??? <-- 40(%esp)
??? <-- 36(%esp)
--> (Automatically pushed by the processor)
%eflags <-- 32(%esp)
%cs <-- 28(%esp)
%eip <-- 24(%esp)
error-code <-- 20(%esp)
--> (Pushed by first lines of ignore_int)
%eax <-- 16(%esp)
%ecx <-- 12(%esp)
%edx <-- 8(%esp)
%es <-- 4(%esp)
%ds <-- %esp

Does 40(%esp) hold a meaningfule value here ?. Also why passing 4 arguments after
the string to prinkt while the string only has 3 conversion specifications (i.e.,
3 * %p) ?.

Best regards,

Ahmed S. Darwish
HomePage: http://darwish.07.googlepages.com
Blog: http://darwish-07.blogspot.com
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