1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #include <linux/module.h>
7 #include <linux/memblock.h>
8 #include <linux/mm.h>
9 #include <linux/pfn.h>
10 #include <asm/page.h>
11 #include <asm/sections.h>
12 #include <as-layout.h>
13 #include <init.h>
14 #include <kern.h>
15 #include <kern_util.h>
16 #include <mem_user.h>
17 #include <os.h>
18
19 static int physmem_fd = -1;
20
21 /* Changed during early boot */
22 unsigned long high_physmem;
23 EXPORT_SYMBOL(high_physmem);
24
25 extern unsigned long long physmem_size;
26
27 void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
28 unsigned long highmem)
29 {
30 unsigned long phys_pages, highmem_pages;
31 unsigned long iomem_pages, total_pages;
32
33 phys_pages = physmem >> PAGE_SHIFT;
34 iomem_pages = iomem >> PAGE_SHIFT;
35 highmem_pages = highmem >> PAGE_SHIFT;
36
37 total_pages = phys_pages + iomem_pages + highmem_pages;
38
39 max_mapnr = total_pages;
40 }
41
42 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
43 int r, int w, int x)
44 {
45 __u64 offset;
46 int fd, err;
47
48 fd = phys_mapping(phys, &offset);
49 err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
50 if (err) {
51 if (err == -ENOMEM)
52 printk(KERN_ERR "try increasing the host's "
53 "/proc/sys/vm/max_map_count to <physical "
54 "memory size>/4096\n");
55 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
56 "err = %d\n", virt, fd, offset, len, r, w, x, err);
57 }
58 }
59
60 /**
61 * setup_physmem() - Setup physical memory for UML
62 * @start: Start address of the physical kernel memory,
63 * i.e start address of the executable image.
64 * @reserve_end: end address of the physical kernel memory.
65 * @len: Length of total physical memory that should be mapped/made
66 * available, in bytes.
67 * @highmem: Number of highmem bytes that should be mapped/made available.
68 *
69 * Creates an unlinked temporary file of size (len + highmem) and memory maps
70 * it on the last executable image address (uml_reserved).
71 *
72 * The offset is needed as the length of the total physical memory
73 * (len + highmem) includes the size of the memory used be the executable image,
74 * but the mapped-to address is the last address of the executable image
75 * (uml_reserved == end address of executable image).
76 *
77 * The memory mapped memory of the temporary file is used as backing memory
78 * of all user space processes/kernel tasks.
79 */
80 void __init setup_physmem(unsigned long start, unsigned long reserve_end,
81 unsigned long len, unsigned long long highmem)
82 {
83 unsigned long reserve = reserve_end - start;
84 long map_size = len - reserve;
85 int err;
86
87 if(map_size <= 0) {
88 os_warn("Too few physical memory! Needed=%lu, given=%lu\n",
89 reserve, len);
90 exit(1);
91 }
92
93 physmem_fd = create_mem_file(len + highmem);
94
95 err = os_map_memory((void *) reserve_end, physmem_fd, reserve,
96 map_size, 1, 1, 1);
97 if (err < 0) {
98 os_warn("setup_physmem - mapping %ld bytes of memory at 0x%p "
99 "failed - errno = %d\n", map_size,
100 (void *) reserve_end, err);
101 exit(1);
102 }
103
104 /*
105 * Special kludge - This page will be mapped in to userspace processes
106 * from physmem_fd, so it needs to be written out there.
107 */
108 os_seek_file(physmem_fd, __pa(__syscall_stub_start));
109 os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE);
110 os_fsync_file(physmem_fd);
111
112 memblock_add(__pa(start), len + highmem);
113 memblock_reserve(__pa(start), reserve);
114
115 min_low_pfn = PFN_UP(__pa(reserve_end));
116 max_low_pfn = min_low_pfn + (map_size >> PAGE_SHIFT);
117 }
118
119 int phys_mapping(unsigned long phys, unsigned long long *offset_out)
120 {
121 int fd = -1;
122
123 if (phys < physmem_size) {
124 fd = physmem_fd;
125 *offset_out = phys;
126 }
127 else if (phys < __pa(end_iomem)) {
128 struct iomem_region *region = iomem_regions;
129
130 while (region != NULL) {
131 if ((phys >= region->phys) &&
132 (phys < region->phys + region->size)) {
133 fd = region->fd;
134 *offset_out = phys - region->phys;
135 break;
136 }
137 region = region->next;
138 }
139 }
140 else if (phys < __pa(end_iomem) + highmem) {
141 fd = physmem_fd;
142 *offset_out = phys - iomem_size;
143 }
144
145 return fd;
146 }
147 EXPORT_SYMBOL(phys_mapping);
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 __uml_setup("iomem=", parse_iomem,
166 "iomem=<name>,<file>\n"
167 " Configure <file> as an IO memory region named <name>.\n\n"
168 );
169
170 /*
171 * This list is constructed in parse_iomem and addresses filled in
172 * setup_iomem, both of which run during early boot. Afterwards, it's
173 * unchanged.
174 */
175 struct iomem_region *iomem_regions;
176
177 /* Initialized in parse_iomem and unchanged thereafter */
178 int iomem_size;
179
180 unsigned long find_iomem(char *driver, unsigned long *len_out)
181 {
182 struct iomem_region *region = iomem_regions;
183
184 while (region != NULL) {
185 if (!strcmp(region->driver, driver)) {
186 *len_out = region->size;
187 return region->virt;
188 }
189
190 region = region->next;
191 }
192
193 return 0;
194 }
195 EXPORT_SYMBOL(find_iomem);
196
197 static int setup_iomem(void)
198 {
199 struct iomem_region *region = iomem_regions;
200 unsigned long iomem_start = high_physmem + PAGE_SIZE;
201 int err;
202
203 while (region != NULL) {
204 err = os_map_memory((void *) iomem_start, region->fd, 0,
205 region->size, 1, 1, 0);
206 if (err)
207 printk(KERN_ERR "Mapping iomem region for driver '%s' "
208 "failed, errno = %d\n", region->driver, -err);
209 else {
210 region->virt = iomem_start;
211 region->phys = __pa(region->virt);
212 }
213
214 iomem_start += region->size + PAGE_SIZE;
215 region = region->next;
216 }
217
218 return 0;
219 }
220
221 __initcall(setup_iomem);
222
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