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 * Copyright 2008 Freescale Semiconductor Inc.
11 * Port to powerpc added by Kumar Gala
19 #include <asm/pgtable.h>
21 #include <linux/threads.h>
22 #include <asm/kmap_types.h>
26 #include <asm/kasan.h>
27 #define FIXADDR_TOP (KASAN_SHADOW_START - PAGE_SIZE)
29 #define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
33 * Here we define all the compile-time 'special' virtual
34 * addresses. The point is to have a constant address at
35 * compile time, but to set the physical address only
36 * in the boot process. We allocate these special addresses
37 * from the end of virtual memory (0xfffff000) backwards.
38 * Also this lets us do fail-safe vmalloc(), we
39 * can guarantee that these special addresses and
40 * vmalloc()-ed addresses never overlap.
42 * these 'compile-time allocated' memory buffers are
43 * fixed-size 4k pages. (or larger if used with an increment
44 * highger than 1) use fixmap_set(idx,phys) to associate
45 * physical memory with fixmap indices.
47 * TLB entries of such buffers will not be flushed across
50 enum fixed_addresses {
52 /* reserve the top 128K for early debugging purposes */
53 FIX_EARLY_DEBUG_TOP = FIX_HOLE,
54 FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+((128*1024)/PAGE_SIZE)-1,
56 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
57 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
60 /* For IMMR we need an aligned 512K area */
61 #define FIX_IMMR_SIZE (512 * 1024 / PAGE_SIZE)
63 FIX_IMMR_BASE = __ALIGN_MASK(FIX_IMMR_START, FIX_IMMR_SIZE - 1) - 1 +
67 __end_of_fixed_addresses
70 #define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
71 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
73 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NCG
75 #include <asm-generic/fixmap.h>
77 static inline void __set_fixmap(enum fixed_addresses idx,
78 phys_addr_t phys, pgprot_t flags)
80 map_kernel_page(fix_to_virt(idx), phys, flags);
83 #endif /* !__ASSEMBLY__ */