2 * fixmap.h: compile-time virtual memory allocation
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
8 * Copyright (C) 1998 Ingo Molnar
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
19 #include <linux/threads.h>
20 #include <asm/kmap_types.h>
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 virtual memory (0xfffff000) 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.
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.
38 * TLB entries of such buffers will not be flushed across
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
48 enum fixed_addresses {
49 #define FIX_N_COLOURS 8
51 #ifdef CONFIG_MIPS_MT_SMTC
52 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS * 2),
54 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
57 /* reserved pte's for temporary kernel mappings */
58 FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
59 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
61 __end_of_fixed_addresses
67 * Leave one empty page between vmalloc'ed areas and
68 * the start of the fixmap, and leave one page empty
71 #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
72 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
74 #include <asm-generic/fixmap.h>
76 #define kmap_get_fixmap_pte(vaddr) \
77 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
80 * Called from pgtable_init()
82 extern void fixrange_init(unsigned long start, unsigned long end,