On Fri, Jan 21, 2005 at 09:03:48 -0600, Timur Tabi wrote: > girish shilamkar wrote: > > > user space virtual address are always valid even in kernel e.g > > sys_read( char * _user buff, pos, count); requires to access user > > buffer to perform read. Sure. But it can't be accessed directly. > In the case of system calls, I thought the kernel translated those user > virtual addresses into kernel virtual addresses for the driver. Why the hell would it do it? If you need to access useland, you have copy_from_user and copy_to_user. IIRC there are also variants for copying NUL-terminated strings, but I don't recall their names. ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@xxxxxx>
Attachment:
signature.asc
Description: Digital signature
