Re: How to make mmap'ed kernel buffer non-cacheable

["Daniel J Blueman" <daniel.blueman@gmail.com>]

On 20 Apr, 14:20, Bhuvan Kumar MITTAL <bhuvan.mit...@st.com> wrote:
> Hi,
>   I am working on an audio device driver development on Linux. I have a kernel
> buffer which I have mapped to user space using mmap call from user space. My
> problem is that the data which comes to the kernel buffer is getting dropped in
> user space and I get only 50-60% of the data which is randomly ordered. The user
> to kernel level buffer address translation code is fine and I suspect this data
> dropping is occurring coz the kernel buffer is cacheable. Please suggest me some
> way of making the entire buffer non cacheable. I am stuck on this for quite a while
> now.

You can use rdmsr() in your driver to check if the page attribute
table MSR is available, then find and/or add the right entry in the
table to set in each page's flags. This is documented in the Intel
IA-32 Intel Architecture Software Developer's Manuals at intel.com.

Dan
-- 
Daniel J Blueman