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

[Miles MH Chen <orca.chen@xxxxxxxxx>]

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@xxxxxxxxx> 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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