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
18 #include <linux/kernel.h>
21 #include <linux/threads.h>
22 #include <asm/kmap_types.h>
25 #define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
28 * Here we define all the compile-time 'special' virtual
29 * addresses. The point is to have a constant address at
30 * compile time, but to set the physical address only
31 * in the boot process. We allocate these special addresses
32 * from the end of virtual memory (0xfffff000) backwards.
33 * Also this lets us do fail-safe vmalloc(), we
34 * can guarantee that these special addresses and
35 * vmalloc()-ed addresses never overlap.
37 * these 'compile-time allocated' memory buffers are
38 * fixed-size 4k pages. (or larger if used with an increment
39 * highger than 1) use fixmap_set(idx,phys) to associate
40 * physical memory with fixmap indices.
42 * TLB entries of such buffers will not be flushed across
45 enum fixed_addresses
{
47 /* reserve the top 128K for early debugging purposes */
48 FIX_EARLY_DEBUG_TOP
= FIX_HOLE
,
49 FIX_EARLY_DEBUG_BASE
= FIX_EARLY_DEBUG_TOP
+((128*1024)/PAGE_SIZE
)-1,
51 FIX_KMAP_BEGIN
, /* reserved pte's for temporary kernel mappings */
52 FIX_KMAP_END
= FIX_KMAP_BEGIN
+(KM_TYPE_NR
*NR_CPUS
)-1,
55 /* For IMMR we need an aligned 512K area */
56 #define FIX_IMMR_SIZE (512 * 1024 / PAGE_SIZE)
58 FIX_IMMR_BASE
= __ALIGN_MASK(FIX_IMMR_START
, FIX_IMMR_SIZE
- 1) - 1 +
62 __end_of_fixed_addresses
65 extern void __set_fixmap (enum fixed_addresses idx
,
66 phys_addr_t phys
, pgprot_t flags
);
68 #define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
69 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
71 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NCG
73 #include <asm-generic/fixmap.h>
75 #endif /* !__ASSEMBLY__ */