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 * TLB entries of such buffers will not be flushed across 38 * task switches. 39 */ 40 enum fixed_addresses { 41 #define FIX_N_COLOURS 8 42 #ifdef CONFIG_HIGHMEM 43 /* reserved pte's for temporary kernel mappings */ 44 FIX_KMAP_BEGIN, 45 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, 46 #endif 47 __end_of_fixed_addresses 48 }; 49 50 #define FIXADDR_TOP (CONSISTENT_START - PAGE_SIZE) 51 #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 52 #define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK) 53 54 #include <asm-generic/fixmap.h> 55 56 #define kmap_get_fixmap_pte(vaddr) \ 57 pte_offset_kernel( \ 58 pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \ 59 (vaddr) \ 60 ) 61 62 /* 63 * Called from pgtable_init() 64 */ 65 extern void fixrange_init(unsigned long start, unsigned long end, 66 pgd_t *pgd_base); 67 68 69 #endif 70