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From: Tomko <tomko@haha.com>
To: linux-kernel@vger.kernel.org
Subject: Why system call need to copy the date from the userspace before using it
Date: Wed, 13 Apr 2005 12:21:41 +0800	[thread overview]
Message-ID: <425C9E55.6010607@haha.com> (raw)

Hi all,

I am new to linux , hope someone can help me.
While i am reading the source code of the linux system call , i find 
that the system call need to call copy_from_user() to copy the data from 
user space to kernel space before using it . Why not use it directly as 
the system call has got the address ?  Furthermore , how to distinguish 
between user space and kernel space ?

Thx a lot,

TOM

             reply	other threads:[~2005-04-13  4:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-13  4:21 Tomko [this message]
2005-04-13  5:30 ` Why system call need to copy the date from the userspace before using it Vadim Lobanov
2005-04-13 10:29 ` Jan-Benedict Glaw
2005-04-13 10:43   ` Tomko
2005-04-13 11:10     ` Catalin Marinas
2005-04-14  2:10       ` Tomko
2005-04-14  2:18         ` David Schwartz
2005-04-14 14:05         ` Helge Hafting
2005-04-13 11:33 ` Benjamin Herrenschmidt
2005-04-13 11:59   ` Hacksaw
2005-04-13 12:40     ` Richard B. Johnson
2005-04-13 18:37       ` Theodore Ts'o
2005-04-13 19:20         ` Richard B. Johnson
2005-04-16  4:50           ` Hacksaw
2005-04-16  5:18             ` Vadim Lobanov
2005-04-16  8:30               ` Hacksaw
2005-04-16 19:35                 ` Vadim Lobanov
2005-04-16 23:46             ` David Wagner
  -- strict thread matches above, loose matches on Subject: below --
2005-04-13  6:48 Vadim Lobanov

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