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 */
27int 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 */
38int 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
49static 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
72static 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
112unsigned long
113hugetlb_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
143get_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
154bool __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
165static __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}
172arch_initcall(gigantic_pages_init);
173#endif
174#endif
175