From owner-freebsd-hackers Wed Jan 19 9: 0:17 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from bingnet2.cc.binghamton.edu (bingnet2.cc.binghamton.edu [128.226.1.18]) by hub.freebsd.org (Postfix) with ESMTP id 8097E1524C for ; Wed, 19 Jan 2000 09:00:05 -0800 (PST) (envelope-from zzhang@cs.binghamton.edu) Received: from sol.cs.binghamton.edu (cs1-gw.cs.binghamton.edu [128.226.171.72]) by bingnet2.cc.binghamton.edu (8.9.3/8.9.3) with SMTP id MAA27856 for ; Wed, 19 Jan 2000 12:00:01 -0500 (EST) Date: Wed, 19 Jan 2000 10:45:49 -0500 (EST) From: Zhihui Zhang To: freebsd-hackers@freebsd.org Subject: Accessing user data from kernel Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG When the kernel wants to access any user data, it either copies them into the kernel or maps them into kernel address space. Can anyone tell me the reasons why this is done? When a process enters the kernel mode, the page tables are not changed. I have taken this for granted for a long time without knowing the reasons. Thanks, -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message