GNU Linux-libre 4.14.266-gnu1
[releases.git] / arch / x86 / mm / hugetlbpage.c
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         if (flags & MAP_FIXED) {
162                 if (prepare_hugepage_range(file, addr, len))
163                         return -EINVAL;
164                 return addr;
165         }
166
167         if (addr) {
168                 addr = ALIGN(addr, huge_page_size(h));
169                 vma = find_vma(mm, addr);
170                 if (TASK_SIZE - len >= addr &&
171                     (!vma || addr + len <= vm_start_gap(vma)))
172                         return addr;
173         }
174         if (mm->get_unmapped_area == arch_get_unmapped_area)
175                 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
176                                 pgoff, flags);
177         else
178                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
179                                 pgoff, flags);
180 }
181 #endif /* CONFIG_HUGETLB_PAGE */
182
183 #ifdef CONFIG_X86_64
184 static __init int setup_hugepagesz(char *opt)
185 {
186         unsigned long ps = memparse(opt, &opt);
187         if (ps == PMD_SIZE) {
188                 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
189         } else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) {
190                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
191         } else {
192                 hugetlb_bad_size();
193                 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
194                         ps >> 20);
195                 return 0;
196         }
197         return 1;
198 }
199 __setup("hugepagesz=", setup_hugepagesz);
200
201 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
202 static __init int gigantic_pages_init(void)
203 {
204         /* With compaction or CMA we can allocate gigantic pages at runtime */
205         if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT))
206                 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
207         return 0;
208 }
209 arch_initcall(gigantic_pages_init);
210 #endif
211 #endif