1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * fixmap.h: compile-time virtual memory allocation
4 *
5 * Copyright (C) 1998 Ingo Molnar
6 *
7 * Copyright 2008 Freescale Semiconductor Inc.
8 * Port to powerpc added by Kumar Gala
9 *
10 * Copyright 2011 Michal Simek <monstr@monstr.eu>
11 * Copyright 2011 PetaLogix Qld Pty Ltd
12 * Port to Microblaze
13 */
14
15 #ifndef _ASM_FIXMAP_H
16 #define _ASM_FIXMAP_H
17
18 #ifndef __ASSEMBLY__
19 #include <linux/kernel.h>
20 #include <asm/page.h>
21 #ifdef CONFIG_HIGHMEM
22 #include <linux/threads.h>
23 #include <asm/kmap_size.h>
24 #endif
25
26 #define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
27
28 /*
29 * Here we define all the compile-time 'special' virtual
30 * addresses. The point is to have a constant address at
31 * compile time, but to set the physical address only
32 * in the boot process. We allocate these special addresses
33 * from the end of virtual memory (0xfffff000) backwards.
34 * Also this lets us do fail-safe vmalloc(), we
35 * can guarantee that these special addresses and
36 * vmalloc()-ed addresses never overlap.
37 *
38 * these 'compile-time allocated' memory buffers are
39 * fixed-size 4k pages. (or larger if used with an increment
40 * highger than 1) use fixmap_set(idx,phys) to associate
41 * physical memory with fixmap indices.
42 *
43 * TLB entries of such buffers will not be flushed across
44 * task switches.
45 */
46 enum fixed_addresses {
47 FIX_HOLE,
48 #ifdef CONFIG_HIGHMEM
49 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
50 FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * num_possible_cpus()) - 1,
51 #endif
52 __end_of_fixed_addresses
53 };
54
55 extern void __set_fixmap(enum fixed_addresses idx,
56 phys_addr_t phys, pgprot_t flags);
57
58 #define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
59 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
60
61 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_CI
62
63 #include <asm-generic/fixmap.h>
64
65 #endif /* !__ASSEMBLY__ */
66 #endif
67
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