1 /* 2 * fixmap.h: compile-time virtual memory allocation 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (C) 1998 Ingo Molnar 9 * 10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 11 */ 12 13 #ifndef _ASM_FIXMAP_H 14 #define _ASM_FIXMAP_H 15 16 #include <asm/pgtable.h> 17 #ifdef CONFIG_HIGHMEM 18 #include <linux/threads.h> 19 #include <asm/kmap_types.h> 20 #endif 21 22 /* 23 * Here we define all the compile-time 'special' virtual 24 * addresses. The point is to have a constant address at 25 * compile time, but to set the physical address only 26 * in the boot process. We allocate these special addresses 27 * from the end of the consistent memory region backwards. 28 * Also this lets us do fail-safe vmalloc(), we 29 * can guarantee that these special addresses and 30 * vmalloc()-ed addresses never overlap. 31 * 32 * these 'compile-time allocated' memory buffers are 33 * fixed-size 4k pages. (or larger if used with an increment 34 * higher than 1) use fixmap_set(idx,phys) to associate 35 * physical memory with fixmap indices. 36 */ 37 enum fixed_addresses { 38 #ifdef CONFIG_HIGHMEM 39 /* reserved pte's for temporary kernel mappings */ 40 FIX_KMAP_BEGIN, 41 FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1, 42 #endif 43 __end_of_fixed_addresses 44 }; 45 46 #define FIXADDR_TOP (VMALLOC_START - PAGE_SIZE) 47 #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 48 #define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK) 49 50 #include <asm-generic/fixmap.h> 51 52 #define kmap_get_fixmap_pte(vaddr) \ 53 pte_offset_kernel( \ 54 pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \ 55 (vaddr) \ 56 ) 57 58 #endif 59