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_types.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_TYPE_NR * 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