1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __UM_FIXMAP_H 3 #define __UM_FIXMAP_H 4 5 #include <asm/processor.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 */ 36 enum fixed_addresses { 37 __end_of_fixed_addresses 38 }; 39 40 extern void __set_fixmap (enum fixed_addresses idx, 41 unsigned long phys, pgprot_t flags); 42 43 /* 44 * used by vmalloc.c. 45 * 46 * Leave one empty page between vmalloc'ed areas and 47 * the start of the fixmap, and leave one page empty 48 * at the top of mem.. 49 */ 50 51 #define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE) 52 #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 53 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 54 55 #include <asm-generic/fixmap.h> 56 57 #endif 58