| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 <linux/kernel.h> |
| 17 | #include <linux/threads.h> |
| 18 | #include <asm/page.h> |
| 19 | #ifdef CONFIG_HIGHMEM |
| 20 | #include <asm/kmap_types.h> |
| 21 | #endif |
| 22 | |
| 23 | /* |
| 24 | * Here we define all the compile-time 'special' virtual |
| 25 | * addresses. The point is to have a constant address at |
| 26 | * compile time, but to set the physical address only |
| 27 | * in the boot process. We allocate these special addresses |
| 28 | * from the end of P3 backwards. |
| 29 | * Also this lets us do fail-safe vmalloc(), we |
| 30 | * can guarantee that these special addresses and |
| 31 | * vmalloc()-ed addresses never overlap. |
| 32 | * |
| 33 | * these 'compile-time allocated' memory buffers are |
| 34 | * fixed-size 4k pages. (or larger if used with an increment |
| 35 | * highger than 1) use fixmap_set(idx,phys) to associate |
| 36 | * physical memory with fixmap indices. |
| 37 | * |
| 38 | * TLB entries of such buffers will not be flushed across |
| 39 | * task switches. |
| 40 | */ |
| 41 | |
| 42 | /* |
| 43 | * on UP currently we will have no trace of the fixmap mechanizm, |
| 44 | * no page table allocations, etc. This might change in the |
| 45 | * future, say framebuffers for the console driver(s) could be |
| 46 | * fix-mapped? |
| 47 | */ |
| 48 | enum fixed_addresses { |
| 49 | /* |
| 50 | * The FIX_CMAP entries are used by kmap_coherent() to get virtual |
| 51 | * addresses which are of a known color, and so their values are |
| 52 | * important. __fix_to_virt(FIX_CMAP_END - n) must give an address |
| 53 | * which is the same color as a page (n<<PAGE_SHIFT). |
| 54 | */ |
| 55 | #define FIX_N_COLOURS 8 |
| 56 | FIX_CMAP_BEGIN, |
| 57 | FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1, |
| 58 | |
| 59 | #ifdef CONFIG_HIGHMEM |
| 60 | FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ |
| 61 | FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1, |
| 62 | #endif |
| 63 | |
| 64 | #ifdef CONFIG_IOREMAP_FIXED |
| 65 | /* |
| 66 | * FIX_IOREMAP entries are useful for mapping physical address |
| 67 | * space before ioremap() is useable, e.g. really early in boot |
| 68 | * before kmalloc() is working. |
| 69 | */ |
| 70 | #define FIX_N_IOREMAPS 32 |
| 71 | FIX_IOREMAP_BEGIN, |
| 72 | FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1, |
| 73 | #endif |
| 74 | |
| 75 | __end_of_fixed_addresses |
| 76 | }; |
| 77 | |
| 78 | extern void __set_fixmap(enum fixed_addresses idx, |
| 79 | unsigned long phys, pgprot_t flags); |
| 80 | extern void __clear_fixmap(enum fixed_addresses idx, pgprot_t flags); |
| 81 | |
| 82 | /* |
| 83 | * used by vmalloc.c. |
| 84 | * |
| 85 | * Leave one empty page between vmalloc'ed areas and |
| 86 | * the start of the fixmap, and leave one page empty |
| 87 | * at the top of mem.. |
| 88 | */ |
| 89 | #ifdef CONFIG_SUPERH32 |
| 90 | #define FIXADDR_TOP (P4SEG - PAGE_SIZE) |
| 91 | #else |
| 92 | #define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE)) |
| 93 | #endif |
| 94 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
| 95 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) |
| 96 | |
| 97 | #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE |
| 98 | |
| 99 | #include <asm-generic/fixmap.h> |
| 100 | |
| 101 | #endif |