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/archparam.h> 7 #include <asm/page.h> 8 #include <linux/threads.h> 9 10 /* 11 * Here we define all the compile-time 'special' virtual 12 * addresses. The point is to have a constant address at 13 * compile time, but to set the physical address only 14 * in the boot process. We allocate these special addresses 15 * from the end of virtual memory (0xfffff000) backwards. 16 * Also this lets us do fail-safe vmalloc(), we 17 * can guarantee that these special addresses and 18 * vmalloc()-ed addresses never overlap. 19 * 20 * these 'compile-time allocated' memory buffers are 21 * fixed-size 4k pages. (or larger if used with an increment 22 * highger than 1) use fixmap_set(idx,phys) to associate 23 * physical memory with fixmap indices. 24 * 25 * TLB entries of such buffers will not be flushed across 26 * task switches. 27 */ 28 29 /* 30 * on UP currently we will have no trace of the fixmap mechanizm, 31 * no page table allocations, etc. This might change in the 32 * future, say framebuffers for the console driver(s) could be 33 * fix-mapped? 34 */ 35 enum fixed_addresses { 36 __end_of_fixed_addresses 37 }; 38 39 extern void __set_fixmap (enum fixed_addresses idx, 40 unsigned long phys, pgprot_t flags); 41 42 /* 43 * used by vmalloc.c. 44 * 45 * Leave one empty page between vmalloc'ed areas and 46 * the start of the fixmap, and leave one page empty 47 * at the top of mem.. 48 */ 49 50 #define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE) 51 #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 52 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 53 54 #include <asm-generic/fixmap.h> 55 56 #endif 57