1 /*
2 * Copyright (C) 2006 Hollis Blanchard <hollisb@us.ibm.com>, IBM Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19 #include <linux/mm.h>
20
21 static unsigned long kernel_virtual_offset;
22 static int is_xencomm_initialized;
23
24 /* for xen early printk. It uses console io hypercall which uses xencomm.
25 * However early printk may use it before xencomm initialization.
26 */
27 int
xencomm_is_initialized(void)28 xencomm_is_initialized(void)
29 {
30 return is_xencomm_initialized;
31 }
32
33 void
xencomm_initialize(void)34 xencomm_initialize(void)
35 {
36 kernel_virtual_offset = KERNEL_START - ia64_tpa(KERNEL_START);
37 is_xencomm_initialized = 1;
38 }
39
40 /* Translate virtual address to physical address. */
41 unsigned long
xencomm_vtop(unsigned long vaddr)42 xencomm_vtop(unsigned long vaddr)
43 {
44 struct page *page;
45 struct vm_area_struct *vma;
46
47 if (vaddr == 0)
48 return 0UL;
49
50 if (REGION_NUMBER(vaddr) == 5) {
51 pgd_t *pgd;
52 pud_t *pud;
53 pmd_t *pmd;
54 pte_t *ptep;
55
56 /* On ia64, TASK_SIZE refers to current. It is not initialized
57 during boot.
58 Furthermore the kernel is relocatable and __pa() doesn't
59 work on addresses. */
60 if (vaddr >= KERNEL_START
61 && vaddr < (KERNEL_START + KERNEL_TR_PAGE_SIZE))
62 return vaddr - kernel_virtual_offset;
63
64 /* In kernel area -- virtually mapped. */
65 pgd = pgd_offset_k(vaddr);
66 if (pgd_none(*pgd) || pgd_bad(*pgd))
67 return ~0UL;
68
69 pud = pud_offset(pgd, vaddr);
70 if (pud_none(*pud) || pud_bad(*pud))
71 return ~0UL;
72
73 pmd = pmd_offset(pud, vaddr);
74 if (pmd_none(*pmd) || pmd_bad(*pmd))
75 return ~0UL;
76
77 ptep = pte_offset_kernel(pmd, vaddr);
78 if (!ptep)
79 return ~0UL;
80
81 return (pte_val(*ptep) & _PFN_MASK) | (vaddr & ~PAGE_MASK);
82 }
83
84 if (vaddr > TASK_SIZE) {
85 /* percpu variables */
86 if (REGION_NUMBER(vaddr) == 7 &&
87 REGION_OFFSET(vaddr) >= (1ULL << IA64_MAX_PHYS_BITS))
88 ia64_tpa(vaddr);
89
90 /* kernel address */
91 return __pa(vaddr);
92 }
93
94 /* XXX double-check (lack of) locking */
95 vma = find_extend_vma(current->mm, vaddr);
96 if (!vma)
97 return ~0UL;
98
99 /* We assume the page is modified. */
100 page = follow_page(vma, vaddr, FOLL_WRITE | FOLL_TOUCH);
101 if (!page)
102 return ~0UL;
103
104 return (page_to_pfn(page) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
105 }
106