From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mhs.atenasio.net (root@d112.dial-1.cmb.ma.ultra.net [209.6.64.112]) by kvack.org (8.8.7/8.8.7) with ESMTP id NAA01691 for ; Fri, 2 Apr 1999 13:56:49 -0500 Date: Fri, 2 Apr 1999 13:56:39 -0500 (EST) From: Chris Atenasio Subject: Re: Somw questions [ MAYBE OFFTOPIC ] In-Reply-To: <19990402113555.F9584@uni-koblenz.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Amol Mohite Cc: ralf@uni-koblenz.de, linux-mm@kvack.org List-ID: > 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 ----------------------------------------------------------------------------- Chris Atenasio - Friends don't let friends use Windows. Send mail with subject "send pgp key" or "word of the day" for auto-response. Today's word of the day: masculinity -- To unsubscribe, send a message with 'unsubscribe linux-mm my@address' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/