Hi Ratheesh, On Tue, Apr 1, 2014 at 9:28 AM, ratheesh kannoth <ratheesh.ksz@gmail.com> wrote:

I mmap'ed mmory allocated by kmalloc , to userspace. I can modify data ( in that memory region ) from kernel space or userspace and call flush_dcache_page to get it refected in both kernel and userspace.

This requirement depends on what cache your hardware has. Can you give more details about your processor? If you have VIPT non aliasing cache or PIPT cache, you don't need to do anything.

1) if i modify a value from userspace, is there any other way to flush dcache page from userspace. What i am looking is to avoid context switch ( to get into kernel only to call flush_dcache_page ) ?

Use __clear_cache. But this will result in a system call and do a v7_coherent_user_range in case of armv architectures. Thanks, Arun

Thanks, Ratheesh

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