Stepping through entry.S

Sridhar N (srin@symonds.net)
Wed, 3 Apr 2002 07:55:31 +0530


Hello,
I was trying to trace the handling of the system calls, and to step through
the entry.S on i386 machine. I basically used this:

srin_entryS_debug_mesg: #My addition
.asciz "some relevant message\n"
ALIGN
tracesys: #haven't changed anything here..
.
.
.
jae tracesys_exit
pushl $srin_entryS_debug_mesg #just this
call SYMBOL_NAME(printk) # and this
call *SYMBOL_NAME(sys_call_table)(,%eax,4)
movl %eax,EAX(%esp) # save the return value
tracesys_exit:

Shouldn't this call printk everytime a system call is made or atleast crash
the kernel if something is dead wrong ? ( It isn't .. everything seems normal
as though the printk isn't there ) Also, how can i know the values in the
specific registers in that file ? Specifically, whenever a system call is
made, what registers store what values ? I'm using kernel 2.4.7 on a K6-2.

Sridhar

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