how to use mmap() on a disk file to get a kernel address?

[Miles MH Chen]

HI,

You cannot do this since mmap function is used to map something to your
user space address.
You can remap kernel memory to user space by remap_pfn_range than access
the kernel memory by using the mapped
user space address.

MH


On Thu, Dec 26, 2013 at 3:42 PM, Yu Bi <lazysmartegg at gmail.com> wrote:

> Hi,
>    I try to mmap a file in a linux kernel module. I have tried to use the
> function do_mmap_pgoff. But the address returned is memory virtual
> address in current process' user space, i.e., below the kernel boundary.
> Instead, I want to map the file in the kernel space and get the kernel
> virtual address of the mapped region. Is there any kernel API in Linux
> support this operation? Or I have to reimplement a kernel mmap version ?
>   But reimplement a kernel version mmap() is  not easy I guess. Do you
> have any idea?
>
>
>
>
>
>
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