xref: /linux/arch/x86/include/asm/fixmap.h (revision bb898558)
1 #ifndef ASM_X86__FIXMAP_H
2 #define ASM_X86__FIXMAP_H
3 
4 #ifdef CONFIG_X86_32
5 # include "fixmap_32.h"
6 #else
7 # include "fixmap_64.h"
8 #endif
9 
10 extern int fixmaps_set;
11 
12 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
13 void native_set_fixmap(enum fixed_addresses idx,
14 		       unsigned long phys, pgprot_t flags);
15 
16 #ifndef CONFIG_PARAVIRT
17 static inline void __set_fixmap(enum fixed_addresses idx,
18 				unsigned long phys, pgprot_t flags)
19 {
20 	native_set_fixmap(idx, phys, flags);
21 }
22 #endif
23 
24 #define set_fixmap(idx, phys)				\
25 	__set_fixmap(idx, phys, PAGE_KERNEL)
26 
27 /*
28  * Some hardware wants to get fixmapped without caching.
29  */
30 #define set_fixmap_nocache(idx, phys)			\
31 	__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
32 
33 #define clear_fixmap(idx)			\
34 	__set_fixmap(idx, 0, __pgprot(0))
35 
36 #define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
37 #define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
38 
39 extern void __this_fixmap_does_not_exist(void);
40 
41 /*
42  * 'index to address' translation. If anyone tries to use the idx
43  * directly without translation, we catch the bug with a NULL-deference
44  * kernel oops. Illegal ranges of incoming indices are caught too.
45  */
46 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
47 {
48 	/*
49 	 * this branch gets completely eliminated after inlining,
50 	 * except when someone tries to use fixaddr indices in an
51 	 * illegal way. (such as mixing up address types or using
52 	 * out-of-range indices).
53 	 *
54 	 * If it doesn't get removed, the linker will complain
55 	 * loudly with a reasonably clear error message..
56 	 */
57 	if (idx >= __end_of_fixed_addresses)
58 		__this_fixmap_does_not_exist();
59 
60 	return __fix_to_virt(idx);
61 }
62 
63 static inline unsigned long virt_to_fix(const unsigned long vaddr)
64 {
65 	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
66 	return __virt_to_fix(vaddr);
67 }
68 #endif /* ASM_X86__FIXMAP_H */
69