linux/include/asm-parisc/fixmap.h

#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H

/*
 * This file defines the locations of the fixed mappings on parisc.
 *
 * All of the values in this file are machine virtual addresses.
 *
 * All of the values in this file must be <4GB (because of assembly
 * loading restrictions).  If you place this region anywhere above
 * __PAGE_OFFSET, you must adjust the memory map accordingly */

/* The alias region is used in kernel space to do copy/clear to or
 * from areas congruently mapped with user space.  It is 8MB large
 * and must be 16MB aligned */
#define TMPALIAS_MAP_START	((__PAGE_OFFSET) - 16*1024*1024)
/* This is the kernel area for all maps (vmalloc, dma etc.)  most
 * usually, it extends up to TMPALIAS_MAP_START.  Virtual addresses
 * 0..GATEWAY_PAGE_SIZE are reserved for the gateway page */
#define KERNEL_MAP_START	(GATEWAY_PAGE_SIZE)
#define KERNEL_MAP_END		(TMPALIAS_MAP_START)

#endif