centos man page for virt_to_phys

VIRT_TO_PHYS(9) 					     Public Functions Provided						   VIRT_TO_PHYS(9)

NAME
       virt_to_phys - map virtual addresses to physical

SYNOPSIS
       phys_addr_t virt_to_phys(volatile void * address);

ARGUMENTS
       address
	   address to remap

DESCRIPTION
       The returned physical address is the physical (CPU) mapping for the memory address given. It is only valid to use this function on
       addresses directly mapped or allocated via kmalloc.

       This function does not give bus mappings for DMA transfers. In almost all conceivable cases a device driver should not be using this
       function

AUTHORS
       Matthew Wilcox <matthew@wil.cx>
	   Author.

       Alan Cox <alan@lxorguk.ukuu.org.uk>
	   Author.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							   VIRT_TO_PHYS(9)