1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PARISC64 Huge TLB page support.
4 *
5 * This parisc implementation is heavily based on the SPARC and x86 code.
6 *
7 * Copyright (C) 2015 Helge Deller <deller@gmx.de>
8 */
9
10 #include <linux/fs.h>
11 #include <linux/mm.h>
12 #include <linux/sched/mm.h>
13 #include <linux/hugetlb.h>
14 #include <linux/pagemap.h>
15 #include <linux/sysctl.h>
16
17 #include <asm/mman.h>
18 #include <asm/tlb.h>
19 #include <asm/tlbflush.h>
20 #include <asm/cacheflush.h>
21 #include <asm/mmu_context.h>
22
23
24 unsigned long
25 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
26 unsigned long len, unsigned long pgoff, unsigned long flags)
27 {
28 struct hstate *h = hstate_file(file);
29
30 if (len & ~huge_page_mask(h))
31 return -EINVAL;
32 if (len > TASK_SIZE)
33 return -ENOMEM;
34
35 if (flags & MAP_FIXED)
36 if (prepare_hugepage_range(file, addr, len))
37 return -EINVAL;
38
39 if (addr)
40 addr = ALIGN(addr, huge_page_size(h));
41
42 /* we need to make sure the colouring is OK */
43 return arch_get_unmapped_area(file, addr, len, pgoff, flags);
44 }
45
46
47 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
48 unsigned long addr, unsigned long sz)
49 {
50 pgd_t *pgd;
51 p4d_t *p4d;
52 pud_t *pud;
53 pmd_t *pmd;
54 pte_t *pte = NULL;
55
56 /* We must align the address, because our caller will run
57 * set_huge_pte_at() on whatever we return, which writes out
58 * all of the sub-ptes for the hugepage range. So we have
59 * to give it the first such sub-pte.
60 */
61 addr &= HPAGE_MASK;
62
63 pgd = pgd_offset(mm, addr);
64 p4d = p4d_offset(pgd, addr);
65 pud = pud_alloc(mm, p4d, addr);
66 if (pud) {
67 pmd = pmd_alloc(mm, pud, addr);
68 if (pmd)
69 pte = pte_alloc_huge(mm, pmd, addr);
70 }
71 return pte;
72 }
73
74 pte_t *huge_pte_offset(struct mm_struct *mm,
75 unsigned long addr, unsigned long sz)
76 {
77 pgd_t *pgd;
78 p4d_t *p4d;
79 pud_t *pud;
80 pmd_t *pmd;
81 pte_t *pte = NULL;
82
83 addr &= HPAGE_MASK;
84
85 pgd = pgd_offset(mm, addr);
86 if (!pgd_none(*pgd)) {
87 p4d = p4d_offset(pgd, addr);
88 if (!p4d_none(*p4d)) {
89 pud = pud_offset(p4d, addr);
90 if (!pud_none(*pud)) {
91 pmd = pmd_offset(pud, addr);
92 if (!pmd_none(*pmd))
93 pte = pte_offset_huge(pmd, addr);
94 }
95 }
96 }
97 return pte;
98 }
99
100 /* Purge data and instruction TLB entries. Must be called holding
101 * the pa_tlb_lock. The TLB purge instructions are slow on SMP
102 * machines since the purge must be broadcast to all CPUs.
103 */
104 static inline void purge_tlb_entries_huge(struct mm_struct *mm, unsigned long addr)
105 {
106 int i;
107
108 /* We may use multiple physical huge pages (e.g. 2x1 MB) to emulate
109 * Linux standard huge pages (e.g. 2 MB) */
110 BUILD_BUG_ON(REAL_HPAGE_SHIFT > HPAGE_SHIFT);
111
112 addr &= HPAGE_MASK;
113 addr |= _HUGE_PAGE_SIZE_ENCODING_DEFAULT;
114
115 for (i = 0; i < (1 << (HPAGE_SHIFT-REAL_HPAGE_SHIFT)); i++) {
116 purge_tlb_entries(mm, addr);
117 addr += (1UL << REAL_HPAGE_SHIFT);
118 }
119 }
120
121 /* __set_huge_pte_at() must be called holding the pa_tlb_lock. */
122 static void __set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
123 pte_t *ptep, pte_t entry)
124 {
125 unsigned long addr_start;
126 int i;
127
128 addr &= HPAGE_MASK;
129 addr_start = addr;
130
131 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
132 set_pte(ptep, entry);
133 ptep++;
134
135 addr += PAGE_SIZE;
136 pte_val(entry) += PAGE_SIZE;
137 }
138
139 purge_tlb_entries_huge(mm, addr_start);
140 }
141
142 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
143 pte_t *ptep, pte_t entry, unsigned long sz)
144 {
145 __set_huge_pte_at(mm, addr, ptep, entry);
146 }
147
148
149 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
150 pte_t *ptep)
151 {
152 pte_t entry;
153
154 entry = *ptep;
155 __set_huge_pte_at(mm, addr, ptep, __pte(0));
156
157 return entry;
158 }
159
160
161 void huge_ptep_set_wrprotect(struct mm_struct *mm,
162 unsigned long addr, pte_t *ptep)
163 {
164 pte_t old_pte;
165
166 old_pte = *ptep;
167 __set_huge_pte_at(mm, addr, ptep, pte_wrprotect(old_pte));
168 }
169
170 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
171 unsigned long addr, pte_t *ptep,
172 pte_t pte, int dirty)
173 {
174 int changed;
175 struct mm_struct *mm = vma->vm_mm;
176
177 changed = !pte_same(*ptep, pte);
178 if (changed) {
179 __set_huge_pte_at(mm, addr, ptep, pte);
180 }
181 return changed;
182 }
183
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