1#ifndef __UM_FIXMAP_H 2#define __UM_FIXMAP_H 3 4#include <asm/kmap_types.h> 5#include <asm/archparam.h> 6#include <asm/elf.h> 7 8/* 9 * Here we define all the compile-time 'special' virtual 10 * addresses. The point is to have a constant address at 11 * compile time, but to set the physical address only 12 * in the boot process. We allocate these special addresses 13 * from the end of virtual memory (0xfffff000) backwards. 14 * Also this lets us do fail-safe vmalloc(), we 15 * can guarantee that these special addresses and 16 * vmalloc()-ed addresses never overlap. 17 * 18 * these 'compile-time allocated' memory buffers are 19 * fixed-size 4k pages. (or larger if used with an increment 20 * highger than 1) use fixmap_set(idx,phys) to associate 21 * physical memory with fixmap indices. 22 * 23 * TLB entries of such buffers will not be flushed across 24 * task switches. 25 */ 26 27/* 28 * on UP currently we will have no trace of the fixmap mechanizm, 29 * no page table allocations, etc. This might change in the 30 * future, say framebuffers for the console driver(s) could be 31 * fix-mapped? 32 */ 33enum fixed_addresses { 34#ifdef CONFIG_HIGHMEM 35 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ 36 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, 37#endif 38 __end_of_fixed_addresses 39}; 40 41extern void __set_fixmap (enum fixed_addresses idx, 42 unsigned long phys, pgprot_t flags); 43 44#define set_fixmap(idx, phys) \ 45 __set_fixmap(idx, phys, PAGE_KERNEL) 46/* 47 * Some hardware wants to get fixmapped without caching. 48 */ 49#define set_fixmap_nocache(idx, phys) \ 50 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) 51/* 52 * used by vmalloc.c. 53 * 54 * Leave one empty page between vmalloc'ed areas and 55 * the start of the fixmap, and leave one page empty 56 * at the top of mem.. 57 */ 58extern unsigned long get_kmem_end(void); 59 60#define FIXADDR_TOP (get_kmem_end() - 0x2000) 61#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 62#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 63 64#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) 65#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) 66 67extern void __this_fixmap_does_not_exist(void); 68 69/* 70 * 'index to address' translation. If anyone tries to use the idx 71 * directly without tranlation, we catch the bug with a NULL-deference 72 * kernel oops. Illegal ranges of incoming indices are caught too. 73 */ 74static inline unsigned long fix_to_virt(const unsigned int idx) 75{ 76 /* 77 * this branch gets completely eliminated after inlining, 78 * except when someone tries to use fixaddr indices in an 79 * illegal way. (such as mixing up address types or using 80 * out-of-range indices). 81 * 82 * If it doesn't get removed, the linker will complain 83 * loudly with a reasonably clear error message.. 84 */ 85 if (idx >= __end_of_fixed_addresses) 86 __this_fixmap_does_not_exist(); 87 88 return __fix_to_virt(idx); 89} 90 91static inline unsigned long virt_to_fix(const unsigned long vaddr) 92{ 93 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); 94 return __virt_to_fix(vaddr); 95} 96 97#endif 98