1/*
2 * IA-64 Huge TLB Page Support for Kernel.
3 *
4 * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
5 * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
6 *
7 * Sep, 2003: add numa support
8 * Feb, 2004: dynamic hugetlb page size via boot parameter
9 */
10
11#include <linux/init.h>
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/hugetlb.h>
15#include <linux/pagemap.h>
16#include <linux/module.h>
17#include <linux/sysctl.h>
18#include <linux/log2.h>
19#include <asm/mman.h>
20#include <asm/pgalloc.h>
21#include <asm/tlb.h>
22#include <asm/tlbflush.h>
23
24unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT;
25EXPORT_SYMBOL(hpage_shift);
26
27pte_t *
28huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
29{
30	unsigned long taddr = htlbpage_to_page(addr);
31	pgd_t *pgd;
32	pud_t *pud;
33	pmd_t *pmd;
34	pte_t *pte = NULL;
35
36	pgd = pgd_offset(mm, taddr);
37	pud = pud_alloc(mm, pgd, taddr);
38	if (pud) {
39		pmd = pmd_alloc(mm, pud, taddr);
40		if (pmd)
41			pte = pte_alloc_map(mm, NULL, pmd, taddr);
42	}
43	return pte;
44}
45
46pte_t *
47huge_pte_offset (struct mm_struct *mm, unsigned long addr)
48{
49	unsigned long taddr = htlbpage_to_page(addr);
50	pgd_t *pgd;
51	pud_t *pud;
52	pmd_t *pmd;
53	pte_t *pte = NULL;
54
55	pgd = pgd_offset(mm, taddr);
56	if (pgd_present(*pgd)) {
57		pud = pud_offset(pgd, taddr);
58		if (pud_present(*pud)) {
59			pmd = pmd_offset(pud, taddr);
60			if (pmd_present(*pmd))
61				pte = pte_offset_map(pmd, taddr);
62		}
63	}
64
65	return pte;
66}
67
68int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
69{
70	return 0;
71}
72
73#define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
74
75/*
76 * Don't actually need to do any preparation, but need to make sure
77 * the address is in the right region.
78 */
79int prepare_hugepage_range(struct file *file,
80			unsigned long addr, unsigned long len)
81{
82	if (len & ~HPAGE_MASK)
83		return -EINVAL;
84	if (addr & ~HPAGE_MASK)
85		return -EINVAL;
86	if (REGION_NUMBER(addr) != RGN_HPAGE)
87		return -EINVAL;
88
89	return 0;
90}
91
92struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
93{
94	struct page *page;
95	pte_t *ptep;
96
97	if (REGION_NUMBER(addr) != RGN_HPAGE)
98		return ERR_PTR(-EINVAL);
99
100	ptep = huge_pte_offset(mm, addr);
101	if (!ptep || pte_none(*ptep))
102		return NULL;
103	page = pte_page(*ptep);
104	page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
105	return page;
106}
107int pmd_huge(pmd_t pmd)
108{
109	return 0;
110}
111
112int pud_huge(pud_t pud)
113{
114	return 0;
115}
116
117void hugetlb_free_pgd_range(struct mmu_gather *tlb,
118			unsigned long addr, unsigned long end,
119			unsigned long floor, unsigned long ceiling)
120{
121	/*
122	 * This is called to free hugetlb page tables.
123	 *
124	 * The offset of these addresses from the base of the hugetlb
125	 * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
126	 * the standard free_pgd_range will free the right page tables.
127	 *
128	 * If floor and ceiling are also in the hugetlb region, they
129	 * must likewise be scaled down; but if outside, left unchanged.
130	 */
131
132	addr = htlbpage_to_page(addr);
133	end  = htlbpage_to_page(end);
134	if (REGION_NUMBER(floor) == RGN_HPAGE)
135		floor = htlbpage_to_page(floor);
136	if (REGION_NUMBER(ceiling) == RGN_HPAGE)
137		ceiling = htlbpage_to_page(ceiling);
138
139	free_pgd_range(tlb, addr, end, floor, ceiling);
140}
141
142unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
143		unsigned long pgoff, unsigned long flags)
144{
145	struct vm_unmapped_area_info info;
146
147	if (len > RGN_MAP_LIMIT)
148		return -ENOMEM;
149	if (len & ~HPAGE_MASK)
150		return -EINVAL;
151
152	/* Handle MAP_FIXED */
153	if (flags & MAP_FIXED) {
154		if (prepare_hugepage_range(file, addr, len))
155			return -EINVAL;
156		return addr;
157	}
158
159	/* This code assumes that RGN_HPAGE != 0. */
160	if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
161		addr = HPAGE_REGION_BASE;
162
163	info.flags = 0;
164	info.length = len;
165	info.low_limit = addr;
166	info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
167	info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
168	info.align_offset = 0;
169	return vm_unmapped_area(&info);
170}
171
172static int __init hugetlb_setup_sz(char *str)
173{
174	u64 tr_pages;
175	unsigned long long size;
176
177	if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
178		/*
179		 * shouldn't happen, but just in case.
180		 */
181		tr_pages = 0x15557000UL;
182
183	size = memparse(str, &str);
184	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
185		size <= PAGE_SIZE ||
186		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
187		printk(KERN_WARNING "Invalid huge page size specified\n");
188		return 1;
189	}
190
191	hpage_shift = __ffs(size);
192	/*
193	 * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
194	 * override here with new page shift.
195	 */
196	ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
197	return 0;
198}
199early_param("hugepagesz", hugetlb_setup_sz);
200