On Tue, 06 Aug 2013, nidhi mittal hada wrote:

---------- Forwarded message ----------
From: nidhi mittal hada <redacted>
Date: Tue, Aug 6, 2013 at 2:16 PM
Subject: Understanding disassembly x86 + understanding function call +
parameter pass and stack frame
To: Kernelnewbies <redacted>
Cc: Mulyadi Santosa <redacted>


Hi All,

I am using crash tool to analyze core dump obtained from red hat linux on
x86_64 platform.

And crash tool gives a stack trace of panic.
But its does not show function parameters which were passed in this stack
trace.

So i have to disassemble and understand the value of parameters passed to
these functions, while it panicked.
Which i am not able to understand much.

I would request help in knowing, how to understand disassembled function
call , on x86_64 arch.

Putting some of the doubts..

a)like which sequence the parameters, return address, etc are pushed on
stack?

Not necessarily on the stack. The AMD64 ABI [0] should help you here.
However, without knowledge of assembly I doubt you can achieve very much.

b)Which registers are used, if some registers play some spl. role ?

You'll see in [0].

c)lets say for a program a.c i use gcc -S a.c ...do we have some other
command to generate
somewhat more clear assembly code, may be with some comments in english

Never heard of such a thing. Actually without optimisation, the generated
assembly code from gcc (from all I have seen and remember) is very clear -
sometimes a little bit clumsy, but clear. You should in fact practice with
something like -O2 if you are about to disassemble kernel functions...

Any kind of help in understanding this will be appreciated ..

Regards,
Tobi

[0] http://www.uclibc.org/docs/psABI-x86_64.pdf