xref: /openbmc/linux/arch/x86/include/asm/fixmap.h (revision 9ac8d3fb)
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 extern pte_t *kmap_pte;
13 extern pgprot_t kmap_prot;
14 extern pte_t *pkmap_page_table;
15 
16 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
17 void native_set_fixmap(enum fixed_addresses idx,
18 		       unsigned long phys, pgprot_t flags);
19 
20 #ifndef CONFIG_PARAVIRT
21 static inline void __set_fixmap(enum fixed_addresses idx,
22 				unsigned long phys, pgprot_t flags)
23 {
24 	native_set_fixmap(idx, phys, flags);
25 }
26 #endif
27 
28 #define set_fixmap(idx, phys)				\
29 	__set_fixmap(idx, phys, PAGE_KERNEL)
30 
31 /*
32  * Some hardware wants to get fixmapped without caching.
33  */
34 #define set_fixmap_nocache(idx, phys)			\
35 	__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
36 
37 #define clear_fixmap(idx)			\
38 	__set_fixmap(idx, 0, __pgprot(0))
39 
40 #define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
41 #define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
42 
43 extern void __this_fixmap_does_not_exist(void);
44 
45 /*
46  * 'index to address' translation. If anyone tries to use the idx
47  * directly without translation, we catch the bug with a NULL-deference
48  * kernel oops. Illegal ranges of incoming indices are caught too.
49  */
50 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
51 {
52 	/*
53 	 * this branch gets completely eliminated after inlining,
54 	 * except when someone tries to use fixaddr indices in an
55 	 * illegal way. (such as mixing up address types or using
56 	 * out-of-range indices).
57 	 *
58 	 * If it doesn't get removed, the linker will complain
59 	 * loudly with a reasonably clear error message..
60 	 */
61 	if (idx >= __end_of_fixed_addresses)
62 		__this_fixmap_does_not_exist();
63 
64 	return __fix_to_virt(idx);
65 }
66 
67 static inline unsigned long virt_to_fix(const unsigned long vaddr)
68 {
69 	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
70 	return __virt_to_fix(vaddr);
71 }
72 #endif /* _ASM_X86_FIXMAP_H */
73