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From: Chris Atenasio <chrisa@ultranet.com>
To: Amol Mohite <amol@m-net.arbornet.org>
Cc: ralf@uni-koblenz.de, linux-mm@kvack.org
Subject: Re: Somw questions [ MAYBE OFFTOPIC ]
Date: Fri, 2 Apr 1999 13:56:39 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.05.9904021353340.18457-100000@chris.atenasio.net> (raw)
In-Reply-To: <19990402113555.F9584@uni-koblenz.de>

> A NULL pointer is just yet another invalid address.  There is no special
> test for a NULL pointer.  Most probably for example (char *)0x12345678 will
> be invalid as a pointer as well and treated the same.  The CPU detects this
> when the TLB doesn't have a translation valid for the access being attempted.

Which is why you can do -=*fun*=- things such as:

fd = open("/dev/kmem", O_RDWR);
mmap(0,64000,PROT_READ|PROT_WRITE,MAP_SHARED|MAP_FIXED,fd,0xB8000);

:)   ^                                       ^^^^^^^^^

- Chris
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  reply	other threads:[~1999-04-02 18:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-04-01  9:16 Amol Mohite
1999-04-02  9:35 ` ralf
1999-04-02 18:56   ` Chris Atenasio [this message]
1999-04-05  9:12   ` Amol Mohite
1999-04-06 10:55     ` ralf
1999-04-06 22:51     ` Stephen C. Tweedie

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