uml: userspace files should call libc directly
[linux-2.6.git] / arch / um / kernel / physmem.c
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include "linux/bootmem.h"
7 #include "linux/mm.h"
8 #include "linux/pfn.h"
9 #include "asm/page.h"
10 #include "as-layout.h"
11 #include "init.h"
12 #include "kern.h"
13 #include "mem_user.h"
14 #include "os.h"
15
16 static int physmem_fd = -1;
17
18 /* Changed during early boot */
19 unsigned long high_physmem;
20
21 extern unsigned long long physmem_size;
22
23 int __init init_maps(unsigned long physmem, unsigned long iomem,
24                      unsigned long highmem)
25 {
26         struct page *p, *map;
27         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
28         unsigned long iomem_len, iomem_pages, total_len, total_pages;
29         int i;
30
31         phys_pages = physmem >> PAGE_SHIFT;
32         phys_len = phys_pages * sizeof(struct page);
33
34         iomem_pages = iomem >> PAGE_SHIFT;
35         iomem_len = iomem_pages * sizeof(struct page);
36
37         highmem_pages = highmem >> PAGE_SHIFT;
38         highmem_len = highmem_pages * sizeof(struct page);
39
40         total_pages = phys_pages + iomem_pages + highmem_pages;
41         total_len = phys_len + iomem_len + highmem_len;
42
43         map = alloc_bootmem_low_pages(total_len);
44         if (map == NULL)
45                 return -ENOMEM;
46
47         for (i = 0; i < total_pages; i++) {
48                 p = &map[i];
49                 memset(p, 0, sizeof(struct page));
50                 SetPageReserved(p);
51                 INIT_LIST_HEAD(&p->lru);
52         }
53
54         max_mapnr = total_pages;
55         return 0;
56 }
57
58 /* Changed during early boot */
59 static unsigned long kmem_top = 0;
60
61 unsigned long get_kmem_end(void)
62 {
63         if (kmem_top == 0)
64                 kmem_top = host_task_size - 1024 * 1024;
65         return kmem_top;
66 }
67
68 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
69                 int r, int w, int x)
70 {
71         __u64 offset;
72         int fd, err;
73
74         fd = phys_mapping(phys, &offset);
75         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
76         if (err) {
77                 if (err == -ENOMEM)
78                         printk(KERN_ERR "try increasing the host's "
79                                "/proc/sys/vm/max_map_count to <physical "
80                                "memory size>/4096\n");
81                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
82                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
83         }
84 }
85
86 extern int __syscall_stub_start;
87
88 void __init setup_physmem(unsigned long start, unsigned long reserve_end,
89                           unsigned long len, unsigned long long highmem)
90 {
91         unsigned long reserve = reserve_end - start;
92         int pfn = PFN_UP(__pa(reserve_end));
93         int delta = (len - reserve) >> PAGE_SHIFT;
94         int err, offset, bootmap_size;
95
96         physmem_fd = create_mem_file(len + highmem);
97
98         offset = uml_reserved - uml_physmem;
99         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
100                             len - offset, 1, 1, 1);
101         if (err < 0) {
102                 printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
103                        "failed - errno = %d\n", len - offset,
104                        (void *) uml_reserved, err);
105                 exit(1);
106         }
107
108         /*
109          * Special kludge - This page will be mapped in to userspace processes
110          * from physmem_fd, so it needs to be written out there.
111          */
112         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
113         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
114
115         bootmap_size = init_bootmem(pfn, pfn + delta);
116         free_bootmem(__pa(reserve_end) + bootmap_size,
117                      len - bootmap_size - reserve);
118 }
119
120 int phys_mapping(unsigned long phys, unsigned long long *offset_out)
121 {
122         int fd = -1;
123
124         if (phys < physmem_size) {
125                 fd = physmem_fd;
126                 *offset_out = phys;
127         }
128         else if (phys < __pa(end_iomem)) {
129                 struct iomem_region *region = iomem_regions;
130
131                 while (region != NULL) {
132                         if ((phys >= region->phys) &&
133                             (phys < region->phys + region->size)) {
134                                 fd = region->fd;
135                                 *offset_out = phys - region->phys;
136                                 break;
137                         }
138                         region = region->next;
139                 }
140         }
141         else if (phys < __pa(end_iomem) + highmem) {
142                 fd = physmem_fd;
143                 *offset_out = phys - iomem_size;
144         }
145
146         return fd;
147 }
148
149 static int __init uml_mem_setup(char *line, int *add)
150 {
151         char *retptr;
152         physmem_size = memparse(line,&retptr);
153         return 0;
154 }
155 __uml_setup("mem=", uml_mem_setup,
156 "mem=<Amount of desired ram>\n"
157 "    This controls how much \"physical\" memory the kernel allocates\n"
158 "    for the system. The size is specified as a number followed by\n"
159 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
160 "    This is not related to the amount of memory in the host.  It can\n"
161 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
162 "       Example: mem=64M\n\n"
163 );
164
165 extern int __init parse_iomem(char *str, int *add);
166
167 __uml_setup("iomem=", parse_iomem,
168 "iomem=<name>,<file>\n"
169 "    Configure <file> as an IO memory region named <name>.\n\n"
170 );
171
172 /*
173  * This list is constructed in parse_iomem and addresses filled in in
174  * setup_iomem, both of which run during early boot.  Afterwards, it's
175  * unchanged.
176  */
177 struct iomem_region *iomem_regions = NULL;
178
179 /* Initialized in parse_iomem */
180 int iomem_size = 0;
181
182 unsigned long find_iomem(char *driver, unsigned long *len_out)
183 {
184         struct iomem_region *region = iomem_regions;
185
186         while (region != NULL) {
187                 if (!strcmp(region->driver, driver)) {
188                         *len_out = region->size;
189                         return region->virt;
190                 }
191
192                 region = region->next;
193         }
194
195         return 0;
196 }
197
198 int setup_iomem(void)
199 {
200         struct iomem_region *region = iomem_regions;
201         unsigned long iomem_start = high_physmem + PAGE_SIZE;
202         int err;
203
204         while (region != NULL) {
205                 err = os_map_memory((void *) iomem_start, region->fd, 0,
206                                     region->size, 1, 1, 0);
207                 if (err)
208                         printk(KERN_ERR "Mapping iomem region for driver '%s' "
209                                "failed, errno = %d\n", region->driver, -err);
210                 else {
211                         region->virt = iomem_start;
212                         region->phys = __pa(region->virt);
213                 }
214
215                 iomem_start += region->size + PAGE_SIZE;
216                 region = region->next;
217         }
218
219         return 0;
220 }
221
222 __initcall(setup_iomem);