Re: get_fs() and set_fs() mm_segment_t

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Hi,
On x86 platforms Linux uses FS register to keep the data segment
register with which access user segment register. If a sys_call is made
and the kernel needs to copy data from user space then FS will have the
value USER_DS. Many kernel functions copy or return data from/to user
space. In order to use the same functions to copy/return data from/to
kernel space you need to do the followings:
mm_segment_t* old_fs;
old_fs = get_fs();
set_fs(KERNEL_DS);
/* call the kernel functions */
set_fs(old_fs);

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• Next message: Jon Forsberg: "fealnx.c doesn't go along with my Surecom EP-320X-S"
• Previous message: Mala Anand: "Intel PRO/1000 driver with NAPI patch"
• Maybe in reply to: Lee Hock Nang, Don: "get_fs() and set_fs() mm_segment_t"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

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