/* * fixmap.h: compile-time virtual memory allocation * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1998 Ingo Molnar * * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 */ #ifndef _ASM_FIXMAP_H #define _ASM_FIXMAP_H #include <asm/page.h> #include <spaces.h> #ifdef CONFIG_HIGHMEM #include <linux/threads.h> #include <asm/kmap_types.h> #endif /* * Here we define all the compile-time 'special' virtual * addresses. The point is to have a constant address at * compile time, but to set the physical address only * in the boot process. We allocate these special addresses * from the end of virtual memory (0xfffff000) backwards. * Also this lets us do fail-safe vmalloc(), we * can guarantee that these special addresses and * vmalloc()-ed addresses never overlap. * * these 'compile-time allocated' memory buffers are * fixed-size 4k pages. (or larger if used with an increment * highger than 1) use fixmap_set(idx,phys) to associate * physical memory with fixmap indices. * * TLB entries of such buffers will not be flushed across * task switches. */ /* * on UP currently we will have no trace of the fixmap mechanizm, * no page table allocations, etc. This might change in the * future, say framebuffers for the console driver(s) could be * fix-mapped? */ enum fixed_addresses { #define FIX_N_COLOURS 8 FIX_CMAP_BEGIN, FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2), #ifdef CONFIG_HIGHMEM /* reserved pte's for temporary kernel mappings */ FIX_KMAP_BEGIN = FIX_CMAP_END + 1, FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, #endif __end_of_fixed_addresses }; /* * used by vmalloc.c. * * Leave one empty page between vmalloc'ed areas and * the start of the fixmap, and leave one page empty * at the top of mem.. */ #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #include <asm-generic/fixmap.h> /* * Called from pgtable_init() */ extern void fixrange_init(unsigned long start, unsigned long end, pgd_t *pgd_base); #endif