aboutsummaryrefslogtreecommitdiffstats
path: root/arch/um/kernel/physmem.c
blob: 9034fc8056b485d2eb34cf7af2f20a23dde87b51 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <asm/page.h>
#include <as-layout.h>
#include <init.h>
#include <kern.h>
#include <mem_user.h>
#include <os.h>

static int physmem_fd = -1;

/* Changed during early boot */
unsigned long high_physmem;
EXPORT_SYMBOL(high_physmem);

extern unsigned long long physmem_size;

void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
		     unsigned long highmem)
{
	unsigned long phys_pages, highmem_pages;
	unsigned long iomem_pages, total_pages;

	phys_pages    = physmem >> PAGE_SHIFT;
	iomem_pages   = iomem   >> PAGE_SHIFT;
	highmem_pages = highmem >> PAGE_SHIFT;

	total_pages   = phys_pages + iomem_pages + highmem_pages;

	max_mapnr = total_pages;
}

void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
		int r, int w, int x)
{
	__u64 offset;
	int fd, err;

	fd = phys_mapping(phys, &offset);
	err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
	if (err) {
		if (err == -ENOMEM)
			printk(KERN_ERR "try increasing the host's "
			       "/proc/sys/vm/max_map_count to <physical "
			       "memory size>/4096\n");
		panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
		      "err = %d\n", virt, fd, offset, len, r, w, x, err);
	}
}

extern int __syscall_stub_start;

/**
 * setup_physmem() - Setup physical memory for UML
 * @start:	Start address of the physical kernel memory,
 *		i.e start address of the executable image.
 * @reserve_end:	end address of the physical kernel memory.
 * @len:	Length of total physical memory that should be mapped/made
 *		available, in bytes.
 * @highmem:	Number of highmem bytes that should be mapped/made available.
 *
 * Creates an unlinked temporary file of size (len + highmem) and memory maps
 * it on the last executable image address (uml_reserved).
 *
 * The offset is needed as the length of the total physical memory
 * (len + highmem) includes the size of the memory used be the executable image,
 * but the mapped-to address is the last address of the executable image
 * (uml_reserved == end address of executable image).
 *
 * The memory mapped memory of the temporary file is used as backing memory
 * of all user space processes/kernel tasks.
 */
void __init setup_physmem(unsigned long start, unsigned long reserve_end,
			  unsigned long len, unsigned long long highmem)
{
	unsigned long reserve = reserve_end - start;
	unsigned long pfn = PFN_UP(__pa(reserve_end));
	unsigned long delta = (len - reserve) >> PAGE_SHIFT;
	unsigned long offset, bootmap_size;
	long map_size;
	int err;

	offset = uml_reserved - uml_physmem;
	map_size = len - offset;
	if(map_size <= 0) {
		printf("Too few physical memory! Needed=%d, given=%d\n",
		       offset, len);
		exit(1);
	}

	physmem_fd = create_mem_file(len + highmem);

	err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
			    map_size, 1, 1, 1);
	if (err < 0) {
		printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
		       "failed - errno = %d\n", map_size,
		       (void *) uml_reserved, err);
		exit(1);
	}

	/*
	 * Special kludge - This page will be mapped in to userspace processes
	 * from physmem_fd, so it needs to be written out there.
	 */
	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
	os_fsync_file(physmem_fd);

	bootmap_size = init_bootmem(pfn, pfn + delta);
	free_bootmem(__pa(reserve_end) + bootmap_size,
		     len - bootmap_size - reserve);
}

int phys_mapping(unsigned long phys, unsigned long long *offset_out)
{
	int fd = -1;

	if (phys < physmem_size) {
		fd = physmem_fd;
		*offset_out = phys;
	}
	else if (phys < __pa(end_iomem)) {
		struct iomem_region *region = iomem_regions;

		while (region != NULL) {
			if ((phys >= region->phys) &&
			    (phys < region->phys + region->size)) {
				fd = region->fd;
				*offset_out = phys - region->phys;
				break;
			}
			region = region->next;
		}
	}
	else if (phys < __pa(end_iomem) + highmem) {
		fd = physmem_fd;
		*offset_out = phys - iomem_size;
	}

	return fd;
}

static int __init uml_mem_setup(char *line, int *add)
{
	char *retptr;
	physmem_size = memparse(line,&retptr);
	return 0;
}
__uml_setup("mem=", uml_mem_setup,
"mem=<Amount of desired ram>\n"
"    This controls how much \"physical\" memory the kernel allocates\n"
"    for the system. The size is specified as a number followed by\n"
"    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
"    This is not related to the amount of memory in the host.  It can\n"
"    be more, and the excess, if it's ever used, will just be swapped out.\n"
"	Example: mem=64M\n\n"
);

extern int __init parse_iomem(char *str, int *add);

__uml_setup("iomem=", parse_iomem,
"iomem=<name>,<file>\n"
"    Configure <file> as an IO memory region named <name>.\n\n"
);

/*
 * This list is constructed in parse_iomem and addresses filled in in
 * setup_iomem, both of which run during early boot.  Afterwards, it's
 * unchanged.
 */
struct iomem_region *iomem_regions;

/* Initialized in parse_iomem and unchanged thereafter */
int iomem_size;

unsigned long find_iomem(char *driver, unsigned long *len_out)
{
	struct iomem_region *region = iomem_regions;

	while (region != NULL) {
		if (!strcmp(region->driver, driver)) {
			*len_out = region->size;
			return region->virt;
		}

		region = region->next;
	}

	return 0;
}
EXPORT_SYMBOL(find_iomem);

static int setup_iomem(void)
{
	struct iomem_region *region = iomem_regions;
	unsigned long iomem_start = high_physmem + PAGE_SIZE;
	int err;

	while (region != NULL) {
		err = os_map_memory((void *) iomem_start, region->fd, 0,
				    region->size, 1, 1, 0);
		if (err)
			printk(KERN_ERR "Mapping iomem region for driver '%s' "
			       "failed, errno = %d\n", region->driver, -err);
		else {
			region->virt = iomem_start;
			region->phys = __pa(region->virt);
		}

		iomem_start += region->size + PAGE_SIZE;
		region = region->next;
	}

	return 0;
}

__initcall(setup_iomem);