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/elf.h>
21 
22 /*
23  * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
24  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
25  * Otherwise, returns 0.
26  */
pmd_huge(pmd_t pmd)27 int pmd_huge(pmd_t pmd)
28 {
29 	return !pmd_none(pmd) &&
30 		(pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
31 }
32 
33 /*
34  * pud_huge() returns 1 if @pud is hugetlb related entry, that is normal
35  * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
36  * Otherwise, returns 0.
37  */
pud_huge(pud_t pud)38 int pud_huge(pud_t pud)
39 {
40 #if CONFIG_PGTABLE_LEVELS > 2
41 	return !pud_none(pud) &&
42 		(pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
43 #else
44 	return 0;
45 #endif
46 }
47 
48 #ifdef CONFIG_HUGETLB_PAGE
hugetlb_get_unmapped_area_bottomup(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)49 static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
50 		unsigned long addr, unsigned long len,
51 		unsigned long pgoff, unsigned long flags)
52 {
53 	struct hstate *h = hstate_file(file);
54 	struct vm_unmapped_area_info info;
55 
56 	info.flags = 0;
57 	info.length = len;
58 	info.low_limit = get_mmap_base(1);
59 
60 	/*
61 	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
62 	 * in the full address space.
63 	 */
64 	info.high_limit = in_32bit_syscall() ?
65 		task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
66 
67 	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
68 	info.align_offset = 0;
69 	return vm_unmapped_area(&info);
70 }
71 
hugetlb_get_unmapped_area_topdown(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)72 static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
73 		unsigned long addr, unsigned long len,
74 		unsigned long pgoff, unsigned long flags)
75 {
76 	struct hstate *h = hstate_file(file);
77 	struct vm_unmapped_area_info info;
78 
79 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
80 	info.length = len;
81 	info.low_limit = PAGE_SIZE;
82 	info.high_limit = get_mmap_base(0);
83 
84 	/*
85 	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
86 	 * in the full address space.
87 	 */
88 	if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
89 		info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
90 
91 	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
92 	info.align_offset = 0;
93 	addr = vm_unmapped_area(&info);
94 
95 	/*
96 	 * A failed mmap() very likely causes application failure,
97 	 * so fall back to the bottom-up function here. This scenario
98 	 * can happen with large stack limits and large mmap()
99 	 * allocations.
100 	 */
101 	if (addr & ~PAGE_MASK) {
102 		VM_BUG_ON(addr != -ENOMEM);
103 		info.flags = 0;
104 		info.low_limit = TASK_UNMAPPED_BASE;
105 		info.high_limit = TASK_SIZE_LOW;
106 		addr = vm_unmapped_area(&info);
107 	}
108 
109 	return addr;
110 }
111 
112 unsigned long
hugetlb_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)113 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
114 		unsigned long len, unsigned long pgoff, unsigned long flags)
115 {
116 	struct hstate *h = hstate_file(file);
117 	struct mm_struct *mm = current->mm;
118 	struct vm_area_struct *vma;
119 
120 	if (len & ~huge_page_mask(h))
121 		return -EINVAL;
122 
123 	if (len > TASK_SIZE)
124 		return -ENOMEM;
125 
126 	/* No address checking. See comment at mmap_address_hint_valid() */
127 	if (flags & MAP_FIXED) {
128 		if (prepare_hugepage_range(file, addr, len))
129 			return -EINVAL;
130 		return addr;
131 	}
132 
133 	if (addr) {
134 		addr &= huge_page_mask(h);
135 		if (!mmap_address_hint_valid(addr, len))
136 			goto get_unmapped_area;
137 
138 		vma = find_vma(mm, addr);
139 		if (!vma || addr + len <= vm_start_gap(vma))
140 			return addr;
141 	}
142 
143 get_unmapped_area:
144 	if (mm->get_unmapped_area == arch_get_unmapped_area)
145 		return hugetlb_get_unmapped_area_bottomup(file, addr, len,
146 				pgoff, flags);
147 	else
148 		return hugetlb_get_unmapped_area_topdown(file, addr, len,
149 				pgoff, flags);
150 }
151 #endif /* CONFIG_HUGETLB_PAGE */
152 
153 #ifdef CONFIG_X86_64
arch_hugetlb_valid_size(unsigned long size)154 bool __init arch_hugetlb_valid_size(unsigned long size)
155 {
156 	if (size == PMD_SIZE)
157 		return true;
158 	else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
159 		return true;
160 	else
161 		return false;
162 }
163 
164 #ifdef CONFIG_CONTIG_ALLOC
gigantic_pages_init(void)165 static __init int gigantic_pages_init(void)
166 {
167 	/* With compaction or CMA we can allocate gigantic pages at runtime */
168 	if (boot_cpu_has(X86_FEATURE_GBPAGES))
169 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
170 	return 0;
171 }
172 arch_initcall(gigantic_pages_init);
173 #endif
174 #endif
175