1#ifndef __UM_FIXMAP_H 2#define __UM_FIXMAP_H 3 4#include <asm/processor.h> 5#include <asm/system.h> 6#include <asm/kmap_types.h> 7#include <asm/archparam.h> 8#include <asm/page.h> 9#include <linux/threads.h> 10 11/* 12 * Here we define all the compile-time 'special' virtual 13 * addresses. The point is to have a constant address at 14 * compile time, but to set the physical address only 15 * in the boot process. We allocate these special addresses 16 * from the end of virtual memory (0xfffff000) backwards. 17 * Also this lets us do fail-safe vmalloc(), we 18 * can guarantee that these special addresses and 19 * vmalloc()-ed addresses never overlap. 20 * 21 * these 'compile-time allocated' memory buffers are 22 * fixed-size 4k pages. (or larger if used with an increment 23 * highger than 1) use fixmap_set(idx,phys) to associate 24 * physical memory with fixmap indices. 25 * 26 * TLB entries of such buffers will not be flushed across 27 * task switches. 28 */ 29 30/* 31 * on UP currently we will have no trace of the fixmap mechanizm, 32 * no page table allocations, etc. This might change in the 33 * future, say framebuffers for the console driver(s) could be 34 * fix-mapped? 35 */ 36enum fixed_addresses { 37#ifdef CONFIG_HIGHMEM 38 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ 39 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, 40#endif 41 __end_of_fixed_addresses 42}; 43 44extern void __set_fixmap (enum fixed_addresses idx, 45 unsigned long phys, pgprot_t flags); 46 47#define set_fixmap(idx, phys) \ 48 __set_fixmap(idx, phys, PAGE_KERNEL) 49/* 50 * Some hardware wants to get fixmapped without caching. 51 */ 52#define set_fixmap_nocache(idx, phys) \ 53 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) 54/* 55 * used by vmalloc.c. 56 * 57 * Leave one empty page between vmalloc'ed areas and 58 * the start of the fixmap, and leave one page empty 59 * at the top of mem.. 60 */ 61 62#define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE) 63#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 64#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 65 66#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) 67#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) 68 69extern void __this_fixmap_does_not_exist(void); 70 71/* 72 * 'index to address' translation. If anyone tries to use the idx 73 * directly without tranlation, we catch the bug with a NULL-deference 74 * kernel oops. Illegal ranges of incoming indices are caught too. 75 */ 76static inline unsigned long fix_to_virt(const unsigned int idx) 77{ 78 /* 79 * this branch gets completely eliminated after inlining, 80 * except when someone tries to use fixaddr indices in an 81 * illegal way. (such as mixing up address types or using 82 * out-of-range indices). 83 * 84 * If it doesn't get removed, the linker will complain 85 * loudly with a reasonably clear error message.. 86 */ 87 if (idx >= __end_of_fixed_addresses) 88 __this_fixmap_does_not_exist(); 89 90 return __fix_to_virt(idx); 91} 92 93static inline unsigned long virt_to_fix(const unsigned long vaddr) 94{ 95 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); 96 return __virt_to_fix(vaddr); 97} 98 99#endif 100