1 #ifndef _ASM_X86_PGTABLE_2LEVEL_H
2 #define _ASM_X86_PGTABLE_2LEVEL_H
3 
4 #define pte_ERROR(e) \
5 	pr_err("%s:%d: bad pte %08lx\n", __FILE__, __LINE__, (e).pte_low)
6 #define pgd_ERROR(e) \
7 	pr_err("%s:%d: bad pgd %08lx\n", __FILE__, __LINE__, pgd_val(e))
8 
9 /*
10  * Certain architectures need to do special things when PTEs
11  * within a page table are directly modified.  Thus, the following
12  * hook is made available.
13  */
14 static inline void native_set_pte(pte_t *ptep , pte_t pte)
15 {
16 	*ptep = pte;
17 }
18 
19 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
20 {
21 	*pmdp = pmd;
22 }
23 
24 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
25 {
26 	native_set_pte(ptep, pte);
27 }
28 
29 static inline void native_pmd_clear(pmd_t *pmdp)
30 {
31 	native_set_pmd(pmdp, __pmd(0));
32 }
33 
34 static inline void native_pte_clear(struct mm_struct *mm,
35 				    unsigned long addr, pte_t *xp)
36 {
37 	*xp = native_make_pte(0);
38 }
39 
40 #ifdef CONFIG_SMP
41 static inline pte_t native_ptep_get_and_clear(pte_t *xp)
42 {
43 	return __pte(xchg(&xp->pte_low, 0));
44 }
45 #else
46 #define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
47 #endif
48 
49 #ifdef CONFIG_SMP
50 static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
51 {
52 	return __pmd(xchg((pmdval_t *)xp, 0));
53 }
54 #else
55 #define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
56 #endif
57 
58 /* Bit manipulation helper on pte/pgoff entry */
59 static inline unsigned long pte_bitop(unsigned long value, unsigned int rightshift,
60 				      unsigned long mask, unsigned int leftshift)
61 {
62 	return ((value >> rightshift) & mask) << leftshift;
63 }
64 
65 /*
66  * Bits _PAGE_BIT_PRESENT, _PAGE_BIT_FILE and _PAGE_BIT_PROTNONE are taken,
67  * split up the 29 bits of offset into this range.
68  */
69 #define PTE_FILE_MAX_BITS	29
70 #define PTE_FILE_SHIFT1		(_PAGE_BIT_PRESENT + 1)
71 #define PTE_FILE_SHIFT2		(_PAGE_BIT_FILE + 1)
72 #define PTE_FILE_SHIFT3		(_PAGE_BIT_PROTNONE + 1)
73 #define PTE_FILE_BITS1		(PTE_FILE_SHIFT2 - PTE_FILE_SHIFT1 - 1)
74 #define PTE_FILE_BITS2		(PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1)
75 
76 #define PTE_FILE_MASK1		((1U << PTE_FILE_BITS1) - 1)
77 #define PTE_FILE_MASK2		((1U << PTE_FILE_BITS2) - 1)
78 
79 #define PTE_FILE_LSHIFT2	(PTE_FILE_BITS1)
80 #define PTE_FILE_LSHIFT3	(PTE_FILE_BITS1 + PTE_FILE_BITS2)
81 
82 static __always_inline pgoff_t pte_to_pgoff(pte_t pte)
83 {
84 	return (pgoff_t)
85 		(pte_bitop(pte.pte_low, PTE_FILE_SHIFT1, PTE_FILE_MASK1,  0)		    +
86 		 pte_bitop(pte.pte_low, PTE_FILE_SHIFT2, PTE_FILE_MASK2,  PTE_FILE_LSHIFT2) +
87 		 pte_bitop(pte.pte_low, PTE_FILE_SHIFT3,           -1UL,  PTE_FILE_LSHIFT3));
88 }
89 
90 static __always_inline pte_t pgoff_to_pte(pgoff_t off)
91 {
92 	return (pte_t){
93 		.pte_low =
94 			pte_bitop(off,                0, PTE_FILE_MASK1,  PTE_FILE_SHIFT1) +
95 			pte_bitop(off, PTE_FILE_LSHIFT2, PTE_FILE_MASK2,  PTE_FILE_SHIFT2) +
96 			pte_bitop(off, PTE_FILE_LSHIFT3,           -1UL,  PTE_FILE_SHIFT3) +
97 			_PAGE_FILE,
98 	};
99 }
100 
101 /* Encode and de-code a swap entry */
102 #define SWP_TYPE_BITS (_PAGE_BIT_FILE - _PAGE_BIT_PRESENT - 1)
103 #define SWP_OFFSET_SHIFT (_PAGE_BIT_PROTNONE + 1)
104 
105 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
106 
107 #define __swp_type(x)			(((x).val >> (_PAGE_BIT_PRESENT + 1)) \
108 					 & ((1U << SWP_TYPE_BITS) - 1))
109 #define __swp_offset(x)			((x).val >> SWP_OFFSET_SHIFT)
110 #define __swp_entry(type, offset)	((swp_entry_t) { \
111 					 ((type) << (_PAGE_BIT_PRESENT + 1)) \
112 					 | ((offset) << SWP_OFFSET_SHIFT) })
113 #define __pte_to_swp_entry(pte)		((swp_entry_t) { (pte).pte_low })
114 #define __swp_entry_to_pte(x)		((pte_t) { .pte = (x).val })
115 
116 #endif /* _ASM_X86_PGTABLE_2LEVEL_H */
117