How to align a kmalloc() address in linux

Question

I have a requirement in kernel space wherein i have to program device register with 64K aligned address. Currently i am using kmalloc() to allocate memory but not sure how to align this 64K. Does linux provide a API which does this? Do i need to write my own code to do the same?

Answer 1

Try following approach:

First calling kmem_cache_create(...) function to create a cache pool for your structure which should be 64K aligned like following:

    buff_64k_cachep = kmem_cache_create("buff_64k_cache",
                                     sizeof(struct test_struct),
                                     1<<16, /* 64k alignment */
                                     flags,
                                     );

Then calling kmem_cache_alloc(...) and kmem_cache_free(...) to allocate and free the buffers you needed.