1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * IA-32 Huge TLB Page Support for Kernel.
4 *
5 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
6 */
7
8 #include <linux/init.h>
9 #include <linux/fs.h>
10 #include <linux/mm.h>
11 #include <linux/sched/mm.h>
12 #include <linux/hugetlb.h>
13 #include <linux/pagemap.h>
14 #include <linux/err.h>
15 #include <linux/sysctl.h>
16 #include <linux/compat.h>
17 #include <asm/mman.h>
18 #include <asm/tlb.h>
19 #include <asm/tlbflush.h>
20 #include <asm/pgalloc.h>
21 #include <asm/elf.h>
22 #include <asm/mpx.h>
23
24 #if 0 /* This is just for testing */
25 struct page *
26 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
27 {
28 unsigned long start = address;
29 int length = 1;
30 int nr;
31 struct page *page;
32 struct vm_area_struct *vma;
33
34 vma = find_vma(mm, addr);
35 if (!vma || !is_vm_hugetlb_page(vma))
36 return ERR_PTR(-EINVAL);
37
38 pte = huge_pte_offset(mm, address, vma_mmu_pagesize(vma));
39
40 /* hugetlb should be locked, and hence, prefaulted */
41 WARN_ON(!pte || pte_none(*pte));
42
43 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
44
45 WARN_ON(!PageHead(page));
46
47 return page;
48 }
49
50 int pmd_huge(pmd_t pmd)
51 {
52 return 0;
53 }
54
55 int pud_huge(pud_t pud)
56 {
57 return 0;
58 }
59
60 #else
61
62 /*
63 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
64 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
65 * Otherwise, returns 0.
66 */
67 int pmd_huge(pmd_t pmd)
68 {
69 return !pmd_none(pmd) &&
70 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
71 }
72
73 int pud_huge(pud_t pud)
74 {
75 return !!(pud_val(pud) & _PAGE_PSE);
76 }
77 #endif
78
79 #ifdef CONFIG_HUGETLB_PAGE
80 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
81 unsigned long addr, unsigned long len,
82 unsigned long pgoff, unsigned long flags)
83 {
84 struct hstate *h = hstate_file(file);
85 struct vm_unmapped_area_info info;
86
87 info.flags = 0;
88 info.length = len;
89 info.low_limit = get_mmap_base(1);
90
91 /*
92 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
93 * in the full address space.
94 */
95 info.high_limit = in_compat_syscall() ?
96 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
97
98 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
99 info.align_offset = 0;
100 return vm_unmapped_area(&info);
101 }
102
103 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
104 unsigned long addr, unsigned long len,
105 unsigned long pgoff, unsigned long flags)
106 {
107 struct hstate *h = hstate_file(file);
108 struct vm_unmapped_area_info info;
109
110 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
111 info.length = len;
112 info.low_limit = PAGE_SIZE;
113 info.high_limit = get_mmap_base(0);
114
115 /*
116 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
117 * in the full address space.
118 */
119 if (addr > DEFAULT_MAP_WINDOW && !in_compat_syscall())
120 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
121
122 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
123 info.align_offset = 0;
124 addr = vm_unmapped_area(&info);
125
126 /*
127 * A failed mmap() very likely causes application failure,
128 * so fall back to the bottom-up function here. This scenario
129 * can happen with large stack limits and large mmap()
130 * allocations.
131 */
132 if (addr & ~PAGE_MASK) {
133 VM_BUG_ON(addr != -ENOMEM);
134 info.flags = 0;
135 info.low_limit = TASK_UNMAPPED_BASE;
136 info.high_limit = TASK_SIZE_LOW;
137 addr = vm_unmapped_area(&info);
138 }
139
140 return addr;
141 }
142
143 unsigned long
144 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
145 unsigned long len, unsigned long pgoff, unsigned long flags)
146 {
147 struct hstate *h = hstate_file(file);
148 struct mm_struct *mm = current->mm;
149 struct vm_area_struct *vma;
150
151 if (len & ~huge_page_mask(h))
152 return -EINVAL;
153
154 addr = mpx_unmapped_area_check(addr, len, flags);
155 if (IS_ERR_VALUE(addr))
156 return addr;
157
158 if (len > TASK_SIZE)
159 return -ENOMEM;
160
161 /* No address checking. See comment at mmap_address_hint_valid() */
162 if (flags & MAP_FIXED) {
163 if (prepare_hugepage_range(file, addr, len))
164 return -EINVAL;
165 return addr;
166 }
167
168 if (addr) {
169 addr &= huge_page_mask(h);
170 if (!mmap_address_hint_valid(addr, len))
171 goto get_unmapped_area;
172
173 vma = find_vma(mm, addr);
174 if (!vma || addr + len <= vm_start_gap(vma))
175 return addr;
176 }
177
178 get_unmapped_area:
179 if (mm->get_unmapped_area == arch_get_unmapped_area)
180 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
181 pgoff, flags);
182 else
183 return hugetlb_get_unmapped_area_topdown(file, addr, len,
184 pgoff, flags);
185 }
186 #endif /* CONFIG_HUGETLB_PAGE */
187
188 #ifdef CONFIG_X86_64
189 static __init int setup_hugepagesz(char *opt)
190 {
191 unsigned long ps = memparse(opt, &opt);
192 if (ps == PMD_SIZE) {
193 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
194 } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) {
195 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
196 } else {
197 hugetlb_bad_size();
198 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
199 ps >> 20);
200 return 0;
201 }
202 return 1;
203 }
204 __setup("hugepagesz=", setup_hugepagesz);
205
206 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
207 static __init int gigantic_pages_init(void)
208 {
209 /* With compaction or CMA we can allocate gigantic pages at runtime */
210 if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT))
211 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
212 return 0;
213 }
214 arch_initcall(gigantic_pages_init);
215 #endif
216 #endif
217
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