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 */
46enum 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
55extern 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