1*4882a593Smuzhiyun /* 2*4882a593Smuzhiyun * fixmap.h: compile-time virtual memory allocation 3*4882a593Smuzhiyun * 4*4882a593Smuzhiyun * This file is subject to the terms and conditions of the GNU General Public 5*4882a593Smuzhiyun * License. See the file "COPYING" in the main directory of this archive 6*4882a593Smuzhiyun * for more details. 7*4882a593Smuzhiyun * 8*4882a593Smuzhiyun * Copyright (C) 1998 Ingo Molnar 9*4882a593Smuzhiyun * 10*4882a593Smuzhiyun * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 11*4882a593Smuzhiyun */ 12*4882a593Smuzhiyun 13*4882a593Smuzhiyun #ifndef _ASM_FIXMAP_H 14*4882a593Smuzhiyun #define _ASM_FIXMAP_H 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun #include <asm/page.h> 17*4882a593Smuzhiyun #include <spaces.h> 18*4882a593Smuzhiyun #ifdef CONFIG_HIGHMEM 19*4882a593Smuzhiyun #include <linux/threads.h> 20*4882a593Smuzhiyun #include <asm/kmap_types.h> 21*4882a593Smuzhiyun #endif 22*4882a593Smuzhiyun 23*4882a593Smuzhiyun /* 24*4882a593Smuzhiyun * Here we define all the compile-time 'special' virtual 25*4882a593Smuzhiyun * addresses. The point is to have a constant address at 26*4882a593Smuzhiyun * compile time, but to set the physical address only 27*4882a593Smuzhiyun * in the boot process. We allocate these special addresses 28*4882a593Smuzhiyun * from the end of virtual memory (0xfffff000) backwards. 29*4882a593Smuzhiyun * Also this lets us do fail-safe vmalloc(), we 30*4882a593Smuzhiyun * can guarantee that these special addresses and 31*4882a593Smuzhiyun * vmalloc()-ed addresses never overlap. 32*4882a593Smuzhiyun * 33*4882a593Smuzhiyun * these 'compile-time allocated' memory buffers are 34*4882a593Smuzhiyun * fixed-size 4k pages. (or larger if used with an increment 35*4882a593Smuzhiyun * highger than 1) use fixmap_set(idx,phys) to associate 36*4882a593Smuzhiyun * physical memory with fixmap indices. 37*4882a593Smuzhiyun * 38*4882a593Smuzhiyun * TLB entries of such buffers will not be flushed across 39*4882a593Smuzhiyun * task switches. 40*4882a593Smuzhiyun */ 41*4882a593Smuzhiyun 42*4882a593Smuzhiyun /* 43*4882a593Smuzhiyun * on UP currently we will have no trace of the fixmap mechanizm, 44*4882a593Smuzhiyun * no page table allocations, etc. This might change in the 45*4882a593Smuzhiyun * future, say framebuffers for the console driver(s) could be 46*4882a593Smuzhiyun * fix-mapped? 47*4882a593Smuzhiyun */ 48*4882a593Smuzhiyun enum fixed_addresses { 49*4882a593Smuzhiyun #define FIX_N_COLOURS 8 50*4882a593Smuzhiyun FIX_CMAP_BEGIN, 51*4882a593Smuzhiyun FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2), 52*4882a593Smuzhiyun #ifdef CONFIG_HIGHMEM 53*4882a593Smuzhiyun /* reserved pte's for temporary kernel mappings */ 54*4882a593Smuzhiyun FIX_KMAP_BEGIN = FIX_CMAP_END + 1, 55*4882a593Smuzhiyun FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, 56*4882a593Smuzhiyun #endif 57*4882a593Smuzhiyun __end_of_fixed_addresses 58*4882a593Smuzhiyun }; 59*4882a593Smuzhiyun 60*4882a593Smuzhiyun /* 61*4882a593Smuzhiyun * used by vmalloc.c. 62*4882a593Smuzhiyun * 63*4882a593Smuzhiyun * Leave one empty page between vmalloc'ed areas and 64*4882a593Smuzhiyun * the start of the fixmap, and leave one page empty 65*4882a593Smuzhiyun * at the top of mem.. 66*4882a593Smuzhiyun */ 67*4882a593Smuzhiyun #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 68*4882a593Smuzhiyun #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 69*4882a593Smuzhiyun 70*4882a593Smuzhiyun #include <asm-generic/fixmap.h> 71*4882a593Smuzhiyun 72*4882a593Smuzhiyun /* 73*4882a593Smuzhiyun * Called from pgtable_init() 74*4882a593Smuzhiyun */ 75*4882a593Smuzhiyun extern void fixrange_init(unsigned long start, unsigned long end, 76*4882a593Smuzhiyun pgd_t *pgd_base); 77*4882a593Smuzhiyun 78*4882a593Smuzhiyun 79*4882a593Smuzhiyun #endif 80