1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __UM_FIXMAP_H
 3#define __UM_FIXMAP_H
 4
 5#include <asm/processor.h>
 
 
 6#include <asm/archparam.h>
 7#include <asm/page.h>
 8#include <linux/threads.h>
 9
10/*
11 * Here we define all the compile-time 'special' virtual
12 * addresses. The point is to have a constant address at
13 * compile time, but to set the physical address only
14 * in the boot process. We allocate these special  addresses
15 * from the end of virtual memory (0xfffff000) backwards.
16 * Also this lets us do fail-safe vmalloc(), we
17 * can guarantee that these special addresses and
18 * vmalloc()-ed addresses never overlap.
19 *
20 * these 'compile-time allocated' memory buffers are
21 * fixed-size 4k pages. (or larger if used with an increment
22 * highger than 1) use fixmap_set(idx,phys) to associate
23 * physical memory with fixmap indices.
24 *
25 * TLB entries of such buffers will not be flushed across
26 * task switches.
27 */
28
29/*
30 * on UP currently we will have no trace of the fixmap mechanizm,
31 * no page table allocations, etc. This might change in the
32 * future, say framebuffers for the console driver(s) could be
33 * fix-mapped?
34 */
35enum fixed_addresses {
 
 
 
 
36	__end_of_fixed_addresses
37};
38
39extern void __set_fixmap (enum fixed_addresses idx,
40			  unsigned long phys, pgprot_t flags);
41
 
 
 
 
 
 
 
42/*
43 * used by vmalloc.c.
44 *
45 * Leave one empty page between vmalloc'ed areas and
46 * the start of the fixmap, and leave one page empty
47 * at the top of mem..
48 */
49
50#define FIXADDR_TOP	(TASK_SIZE - 2 * PAGE_SIZE)
51#define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)
52#define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)
53
54#include <asm-generic/fixmap.h>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
55
56#endif

 
 1#ifndef __UM_FIXMAP_H
 2#define __UM_FIXMAP_H
 3
 4#include <asm/processor.h>
 5#include <asm/system.h>
 6#include <asm/kmap_types.h>
 7#include <asm/archparam.h>
 8#include <asm/page.h>
 9#include <linux/threads.h>
10
11/*
12 * Here we define all the compile-time 'special' virtual
13 * addresses. The point is to have a constant address at
14 * compile time, but to set the physical address only
15 * in the boot process. We allocate these special  addresses
16 * from the end of virtual memory (0xfffff000) backwards.
17 * Also this lets us do fail-safe vmalloc(), we
18 * can guarantee that these special addresses and
19 * vmalloc()-ed addresses never overlap.
20 *
21 * these 'compile-time allocated' memory buffers are
22 * fixed-size 4k pages. (or larger if used with an increment
23 * highger than 1) use fixmap_set(idx,phys) to associate
24 * physical memory with fixmap indices.
25 *
26 * TLB entries of such buffers will not be flushed across
27 * task switches.
28 */
29
30/*
31 * on UP currently we will have no trace of the fixmap mechanizm,
32 * no page table allocations, etc. This might change in the
33 * future, say framebuffers for the console driver(s) could be
34 * fix-mapped?
35 */
36enum fixed_addresses {
37#ifdef CONFIG_HIGHMEM
38	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
39	FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
40#endif
41	__end_of_fixed_addresses
42};
43
44extern void __set_fixmap (enum fixed_addresses idx,
45			  unsigned long phys, pgprot_t flags);
46
47#define set_fixmap(idx, phys) \
48		__set_fixmap(idx, phys, PAGE_KERNEL)
49/*
50 * Some hardware wants to get fixmapped without caching.
51 */
52#define set_fixmap_nocache(idx, phys) \
53		__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
54/*
55 * used by vmalloc.c.
56 *
57 * Leave one empty page between vmalloc'ed areas and
58 * the start of the fixmap, and leave one page empty
59 * at the top of mem..
60 */
61
62#define FIXADDR_TOP	(TASK_SIZE - 2 * PAGE_SIZE)
63#define FIXADDR_SIZE	(__end_of_fixed_addresses << PAGE_SHIFT)
64#define FIXADDR_START	(FIXADDR_TOP - FIXADDR_SIZE)
65
66#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
67#define __virt_to_fix(x)      ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
68
69extern void __this_fixmap_does_not_exist(void);
70
71/*
72 * 'index to address' translation. If anyone tries to use the idx
73 * directly without tranlation, we catch the bug with a NULL-deference
74 * kernel oops. Illegal ranges of incoming indices are caught too.
75 */
76static inline unsigned long fix_to_virt(const unsigned int idx)
77{
78	/*
79	 * this branch gets completely eliminated after inlining,
80	 * except when someone tries to use fixaddr indices in an
81	 * illegal way. (such as mixing up address types or using
82	 * out-of-range indices).
83	 *
84	 * If it doesn't get removed, the linker will complain
85	 * loudly with a reasonably clear error message..
86	 */
87	if (idx >= __end_of_fixed_addresses)
88		__this_fixmap_does_not_exist();
89
90        return __fix_to_virt(idx);
91}
92
93static inline unsigned long virt_to_fix(const unsigned long vaddr)
94{
95      BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
96      return __virt_to_fix(vaddr);
97}
98
99#endif