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#if 0	/* This is just for testing */
23struct page *
24follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
25{
26	unsigned long start = address;
27	int length = 1;
28	int nr;
29	struct page *page;
30	struct vm_area_struct *vma;
31
32	vma = find_vma(mm, addr);
33	if (!vma || !is_vm_hugetlb_page(vma))
34		return ERR_PTR(-EINVAL);
35
36	pte = huge_pte_offset(mm, address, vma_mmu_pagesize(vma));
37
38	/* hugetlb should be locked, and hence, prefaulted */
39	WARN_ON(!pte || pte_none(*pte));
40
41	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
42
43	WARN_ON(!PageHead(page));
44
45	return page;
46}
47
48int pmd_huge(pmd_t pmd)
49{
50	return 0;
51}
52
53int pud_huge(pud_t pud)
54{
55	return 0;
56}
57
58#else
59
60/*
61 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
62 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
63 * Otherwise, returns 0.
64 */
65int pmd_huge(pmd_t pmd)
66{
67	return !pmd_none(pmd) &&
68		(pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
69}
70
71int pud_huge(pud_t pud)
72{
73	return !!(pud_val(pud) & _PAGE_PSE);
74}
75#endif
76
77#ifdef CONFIG_HUGETLB_PAGE
78static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
79		unsigned long addr, unsigned long len,
80		unsigned long pgoff, unsigned long flags)
81{
82	struct hstate *h = hstate_file(file);
83	struct vm_unmapped_area_info info;
84
85	info.flags = 0;
86	info.length = len;
87	info.low_limit = get_mmap_base(1);
88
89	/*
90	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
91	 * in the full address space.
92	 */
93	info.high_limit = in_32bit_syscall() ?
94		task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
95
96	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
97	info.align_offset = 0;
98	return vm_unmapped_area(&info);
99}
100
101static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
102		unsigned long addr, unsigned long len,
103		unsigned long pgoff, unsigned long flags)
104{
105	struct hstate *h = hstate_file(file);
106	struct vm_unmapped_area_info info;
107
108	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
109	info.length = len;
110	info.low_limit = PAGE_SIZE;
111	info.high_limit = get_mmap_base(0);
112
113	/*
114	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
115	 * in the full address space.
116	 */
117	if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
118		info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
119
120	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
121	info.align_offset = 0;
122	addr = vm_unmapped_area(&info);
123
124	/*
125	 * A failed mmap() very likely causes application failure,
126	 * so fall back to the bottom-up function here. This scenario
127	 * can happen with large stack limits and large mmap()
128	 * allocations.
129	 */
130	if (addr & ~PAGE_MASK) {
131		VM_BUG_ON(addr != -ENOMEM);
132		info.flags = 0;
133		info.low_limit = TASK_UNMAPPED_BASE;
134		info.high_limit = TASK_SIZE_LOW;
135		addr = vm_unmapped_area(&info);
136	}
137
138	return addr;
139}
140
141unsigned long
142hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
143		unsigned long len, unsigned long pgoff, unsigned long flags)
144{
145	struct hstate *h = hstate_file(file);
146	struct mm_struct *mm = current->mm;
147	struct vm_area_struct *vma;
148
149	if (len & ~huge_page_mask(h))
150		return -EINVAL;
151
152	if (len > TASK_SIZE)
153		return -ENOMEM;
154
155	/* No address checking. See comment at mmap_address_hint_valid() */
156	if (flags & MAP_FIXED) {
157		if (prepare_hugepage_range(file, addr, len))
158			return -EINVAL;
159		return addr;
160	}
161
162	if (addr) {
163		addr &= huge_page_mask(h);
164		if (!mmap_address_hint_valid(addr, len))
165			goto get_unmapped_area;
166
167		vma = find_vma(mm, addr);
168		if (!vma || addr + len <= vm_start_gap(vma))
169			return addr;
170	}
171
172get_unmapped_area:
173	if (mm->get_unmapped_area == arch_get_unmapped_area)
174		return hugetlb_get_unmapped_area_bottomup(file, addr, len,
175				pgoff, flags);
176	else
177		return hugetlb_get_unmapped_area_topdown(file, addr, len,
178				pgoff, flags);
179}
180#endif /* CONFIG_HUGETLB_PAGE */
181
182#ifdef CONFIG_X86_64
183bool __init arch_hugetlb_valid_size(unsigned long size)
184{
185	if (size == PMD_SIZE)
186		return true;
187	else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
188		return true;
189	else
190		return false;
191}
192
193#ifdef CONFIG_CONTIG_ALLOC
194static __init int gigantic_pages_init(void)
195{
196	/* With compaction or CMA we can allocate gigantic pages at runtime */
197	if (boot_cpu_has(X86_FEATURE_GBPAGES))
198		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
199	return 0;
200}
201arch_initcall(gigantic_pages_init);
202#endif
203#endif
204