1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Common EFI memory map functions.
4 */
5
6 #define pr_fmt(fmt) "efi: " fmt
7
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/efi.h>
11 #include <linux/io.h>
12 #include <asm/early_ioremap.h>
13 #include <linux/memblock.h>
14 #include <linux/slab.h>
15
__efi_memmap_alloc_early(unsigned long size)16 static phys_addr_t __init __efi_memmap_alloc_early(unsigned long size)
17 {
18 return memblock_phys_alloc(size, SMP_CACHE_BYTES);
19 }
20
__efi_memmap_alloc_late(unsigned long size)21 static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
22 {
23 unsigned int order = get_order(size);
24 struct page *p = alloc_pages(GFP_KERNEL, order);
25
26 if (!p)
27 return 0;
28
29 return PFN_PHYS(page_to_pfn(p));
30 }
31
32 /**
33 * efi_memmap_alloc - Allocate memory for the EFI memory map
34 * @num_entries: Number of entries in the allocated map.
35 *
36 * Depending on whether mm_init() has already been invoked or not,
37 * either memblock or "normal" page allocation is used.
38 *
39 * Returns the physical address of the allocated memory map on
40 * success, zero on failure.
41 */
efi_memmap_alloc(unsigned int num_entries)42 phys_addr_t __init efi_memmap_alloc(unsigned int num_entries)
43 {
44 unsigned long size = num_entries * efi.memmap.desc_size;
45
46 if (slab_is_available())
47 return __efi_memmap_alloc_late(size);
48
49 return __efi_memmap_alloc_early(size);
50 }
51
52 /**
53 * __efi_memmap_init - Common code for mapping the EFI memory map
54 * @data: EFI memory map data
55 * @late: Use early or late mapping function?
56 *
57 * This function takes care of figuring out which function to use to
58 * map the EFI memory map in efi.memmap based on how far into the boot
59 * we are.
60 *
61 * During bootup @late should be %false since we only have access to
62 * the early_memremap*() functions as the vmalloc space isn't setup.
63 * Once the kernel is fully booted we can fallback to the more robust
64 * memremap*() API.
65 *
66 * Returns zero on success, a negative error code on failure.
67 */
68 static int __init
__efi_memmap_init(struct efi_memory_map_data * data,bool late)69 __efi_memmap_init(struct efi_memory_map_data *data, bool late)
70 {
71 struct efi_memory_map map;
72 phys_addr_t phys_map;
73
74 if (efi_enabled(EFI_PARAVIRT))
75 return 0;
76
77 phys_map = data->phys_map;
78
79 if (late)
80 map.map = memremap(phys_map, data->size, MEMREMAP_WB);
81 else
82 map.map = early_memremap(phys_map, data->size);
83
84 if (!map.map) {
85 pr_err("Could not map the memory map!\n");
86 return -ENOMEM;
87 }
88
89 map.phys_map = data->phys_map;
90 map.nr_map = data->size / data->desc_size;
91 map.map_end = map.map + data->size;
92
93 map.desc_version = data->desc_version;
94 map.desc_size = data->desc_size;
95 map.late = late;
96
97 set_bit(EFI_MEMMAP, &efi.flags);
98
99 efi.memmap = map;
100
101 return 0;
102 }
103
104 /**
105 * efi_memmap_init_early - Map the EFI memory map data structure
106 * @data: EFI memory map data
107 *
108 * Use early_memremap() to map the passed in EFI memory map and assign
109 * it to efi.memmap.
110 */
efi_memmap_init_early(struct efi_memory_map_data * data)111 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
112 {
113 /* Cannot go backwards */
114 WARN_ON(efi.memmap.late);
115
116 return __efi_memmap_init(data, false);
117 }
118
efi_memmap_unmap(void)119 void __init efi_memmap_unmap(void)
120 {
121 if (!efi_enabled(EFI_MEMMAP))
122 return;
123
124 if (!efi.memmap.late) {
125 unsigned long size;
126
127 size = efi.memmap.desc_size * efi.memmap.nr_map;
128 early_memunmap(efi.memmap.map, size);
129 } else {
130 memunmap(efi.memmap.map);
131 }
132
133 efi.memmap.map = NULL;
134 clear_bit(EFI_MEMMAP, &efi.flags);
135 }
136
137 /**
138 * efi_memmap_init_late - Map efi.memmap with memremap()
139 * @phys_addr: Physical address of the new EFI memory map
140 * @size: Size in bytes of the new EFI memory map
141 *
142 * Setup a mapping of the EFI memory map using ioremap_cache(). This
143 * function should only be called once the vmalloc space has been
144 * setup and is therefore not suitable for calling during early EFI
145 * initialise, e.g. in efi_init(). Additionally, it expects
146 * efi_memmap_init_early() to have already been called.
147 *
148 * The reason there are two EFI memmap initialisation
149 * (efi_memmap_init_early() and this late version) is because the
150 * early EFI memmap should be explicitly unmapped once EFI
151 * initialisation is complete as the fixmap space used to map the EFI
152 * memmap (via early_memremap()) is a scarce resource.
153 *
154 * This late mapping is intended to persist for the duration of
155 * runtime so that things like efi_mem_desc_lookup() and
156 * efi_mem_attributes() always work.
157 *
158 * Returns zero on success, a negative error code on failure.
159 */
efi_memmap_init_late(phys_addr_t addr,unsigned long size)160 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
161 {
162 struct efi_memory_map_data data = {
163 .phys_map = addr,
164 .size = size,
165 };
166
167 /* Did we forget to unmap the early EFI memmap? */
168 WARN_ON(efi.memmap.map);
169
170 /* Were we already called? */
171 WARN_ON(efi.memmap.late);
172
173 /*
174 * It makes no sense to allow callers to register different
175 * values for the following fields. Copy them out of the
176 * existing early EFI memmap.
177 */
178 data.desc_version = efi.memmap.desc_version;
179 data.desc_size = efi.memmap.desc_size;
180
181 return __efi_memmap_init(&data, true);
182 }
183
184 /**
185 * efi_memmap_install - Install a new EFI memory map in efi.memmap
186 * @addr: Physical address of the memory map
187 * @nr_map: Number of entries in the memory map
188 *
189 * Unlike efi_memmap_init_*(), this function does not allow the caller
190 * to switch from early to late mappings. It simply uses the existing
191 * mapping function and installs the new memmap.
192 *
193 * Returns zero on success, a negative error code on failure.
194 */
efi_memmap_install(phys_addr_t addr,unsigned int nr_map)195 int __init efi_memmap_install(phys_addr_t addr, unsigned int nr_map)
196 {
197 struct efi_memory_map_data data;
198
199 efi_memmap_unmap();
200
201 data.phys_map = addr;
202 data.size = efi.memmap.desc_size * nr_map;
203 data.desc_version = efi.memmap.desc_version;
204 data.desc_size = efi.memmap.desc_size;
205
206 return __efi_memmap_init(&data, efi.memmap.late);
207 }
208
209 /**
210 * efi_memmap_split_count - Count number of additional EFI memmap entries
211 * @md: EFI memory descriptor to split
212 * @range: Address range (start, end) to split around
213 *
214 * Returns the number of additional EFI memmap entries required to
215 * accomodate @range.
216 */
efi_memmap_split_count(efi_memory_desc_t * md,struct range * range)217 int __init efi_memmap_split_count(efi_memory_desc_t *md, struct range *range)
218 {
219 u64 m_start, m_end;
220 u64 start, end;
221 int count = 0;
222
223 start = md->phys_addr;
224 end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
225
226 /* modifying range */
227 m_start = range->start;
228 m_end = range->end;
229
230 if (m_start <= start) {
231 /* split into 2 parts */
232 if (start < m_end && m_end < end)
233 count++;
234 }
235
236 if (start < m_start && m_start < end) {
237 /* split into 3 parts */
238 if (m_end < end)
239 count += 2;
240 /* split into 2 parts */
241 if (end <= m_end)
242 count++;
243 }
244
245 return count;
246 }
247
248 /**
249 * efi_memmap_insert - Insert a memory region in an EFI memmap
250 * @old_memmap: The existing EFI memory map structure
251 * @buf: Address of buffer to store new map
252 * @mem: Memory map entry to insert
253 *
254 * It is suggested that you call efi_memmap_split_count() first
255 * to see how large @buf needs to be.
256 */
efi_memmap_insert(struct efi_memory_map * old_memmap,void * buf,struct efi_mem_range * mem)257 void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
258 struct efi_mem_range *mem)
259 {
260 u64 m_start, m_end, m_attr;
261 efi_memory_desc_t *md;
262 u64 start, end;
263 void *old, *new;
264
265 /* modifying range */
266 m_start = mem->range.start;
267 m_end = mem->range.end;
268 m_attr = mem->attribute;
269
270 /*
271 * The EFI memory map deals with regions in EFI_PAGE_SIZE
272 * units. Ensure that the region described by 'mem' is aligned
273 * correctly.
274 */
275 if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
276 !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
277 WARN_ON(1);
278 return;
279 }
280
281 for (old = old_memmap->map, new = buf;
282 old < old_memmap->map_end;
283 old += old_memmap->desc_size, new += old_memmap->desc_size) {
284
285 /* copy original EFI memory descriptor */
286 memcpy(new, old, old_memmap->desc_size);
287 md = new;
288 start = md->phys_addr;
289 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
290
291 if (m_start <= start && end <= m_end)
292 md->attribute |= m_attr;
293
294 if (m_start <= start &&
295 (start < m_end && m_end < end)) {
296 /* first part */
297 md->attribute |= m_attr;
298 md->num_pages = (m_end - md->phys_addr + 1) >>
299 EFI_PAGE_SHIFT;
300 /* latter part */
301 new += old_memmap->desc_size;
302 memcpy(new, old, old_memmap->desc_size);
303 md = new;
304 md->phys_addr = m_end + 1;
305 md->num_pages = (end - md->phys_addr + 1) >>
306 EFI_PAGE_SHIFT;
307 }
308
309 if ((start < m_start && m_start < end) && m_end < end) {
310 /* first part */
311 md->num_pages = (m_start - md->phys_addr) >>
312 EFI_PAGE_SHIFT;
313 /* middle part */
314 new += old_memmap->desc_size;
315 memcpy(new, old, old_memmap->desc_size);
316 md = new;
317 md->attribute |= m_attr;
318 md->phys_addr = m_start;
319 md->num_pages = (m_end - m_start + 1) >>
320 EFI_PAGE_SHIFT;
321 /* last part */
322 new += old_memmap->desc_size;
323 memcpy(new, old, old_memmap->desc_size);
324 md = new;
325 md->phys_addr = m_end + 1;
326 md->num_pages = (end - m_end) >>
327 EFI_PAGE_SHIFT;
328 }
329
330 if ((start < m_start && m_start < end) &&
331 (end <= m_end)) {
332 /* first part */
333 md->num_pages = (m_start - md->phys_addr) >>
334 EFI_PAGE_SHIFT;
335 /* latter part */
336 new += old_memmap->desc_size;
337 memcpy(new, old, old_memmap->desc_size);
338 md = new;
339 md->phys_addr = m_start;
340 md->num_pages = (end - md->phys_addr + 1) >>
341 EFI_PAGE_SHIFT;
342 md->attribute |= m_attr;
343 }
344 }
345 }
346
