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From: Brian Gerst <bgerst@didntduck.org>
To: Raman S <raman_s_@hotmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: int 0x40
Date: Fri, 18 Jan 2002 12:47:33 -0500	[thread overview]
Message-ID: <3C485FB5.FC5CB8C3@didntduck.org> (raw)
In-Reply-To: <F49lHiu3fQtYdVzDpub0001e2cc@hotmail.com>

Raman S wrote:
> 
> Hi,
>   I relatively new to the kernel and am trying to understand how the linux
> kernel handles interrupts. For this I attempted to
> create an int 0x40 by adding a set_system_gate(64, &system_call) in traps.c.
> I verfied by giving out print statements within set_system_gate that 64 is
> being set during initialization (though it isnt a surprise that it is being
> set).  But when i give an int 0x40 in a user level assembly program I get
> segmentation fault, (a SIGSEGV signal is sent to the process).  I have tried
> adding another function in entry.S called my_system_call and reproducing the
> code in system_call with a jmp ret_from_sys_call  at the end. Also tried
> giving an empty C function for my_system_call all with the same result.

The IRQ setup code is probably overwriting it.  You'll need to make the
code in i8259.c skip over vector 0x40 as well as SYSCALL_VECTOR (0x80).

--

				Brian Gerst

  parent reply	other threads:[~2002-01-18 17:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-18 16:26 int 0x40 Raman S
2002-01-18 17:02 ` Richard B. Johnson
2002-01-18 17:47 ` Brian Gerst [this message]
2002-01-18 18:15   ` Richard B. Johnson
  -- strict thread matches above, loose matches on Subject: below --
2002-01-18 19:47 Raman S

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