1 /*
2 * arch/s390/mm/vmem.c
3 *
4 * Copyright IBM Corp. 2006
5 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
6 */
7
8 #include <linux/bootmem.h>
9 #include <linux/pfn.h>
10 #include <linux/mm.h>
11 #include <linux/module.h>
12 #include <linux/list.h>
13 #include <linux/hugetlb.h>
14 #include <linux/slab.h>
15 #include <asm/pgalloc.h>
16 #include <asm/pgtable.h>
17 #include <asm/setup.h>
18 #include <asm/tlbflush.h>
19 #include <asm/sections.h>
20
21 static DEFINE_MUTEX(vmem_mutex);
22
23 struct memory_segment {
24 struct list_head list;
25 unsigned long start;
26 unsigned long size;
27 };
28
29 static LIST_HEAD(mem_segs);
30
vmem_alloc_pages(unsigned int order)31 static void __ref *vmem_alloc_pages(unsigned int order)
32 {
33 if (slab_is_available())
34 return (void *)__get_free_pages(GFP_KERNEL, order);
35 return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
36 }
37
vmem_pud_alloc(void)38 static inline pud_t *vmem_pud_alloc(void)
39 {
40 pud_t *pud = NULL;
41
42 #ifdef CONFIG_64BIT
43 pud = vmem_alloc_pages(2);
44 if (!pud)
45 return NULL;
46 clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
47 #endif
48 return pud;
49 }
50
vmem_pmd_alloc(void)51 static inline pmd_t *vmem_pmd_alloc(void)
52 {
53 pmd_t *pmd = NULL;
54
55 #ifdef CONFIG_64BIT
56 pmd = vmem_alloc_pages(2);
57 if (!pmd)
58 return NULL;
59 clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
60 #endif
61 return pmd;
62 }
63
vmem_pte_alloc(void)64 static pte_t __ref *vmem_pte_alloc(void)
65 {
66 pte_t *pte;
67
68 if (slab_is_available())
69 pte = (pte_t *) page_table_alloc(&init_mm);
70 else
71 pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
72 if (!pte)
73 return NULL;
74 clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
75 PTRS_PER_PTE * sizeof(pte_t));
76 return pte;
77 }
78
79 /*
80 * Add a physical memory range to the 1:1 mapping.
81 */
vmem_add_mem(unsigned long start,unsigned long size,int ro)82 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
83 {
84 unsigned long address;
85 pgd_t *pg_dir;
86 pud_t *pu_dir;
87 pmd_t *pm_dir;
88 pte_t *pt_dir;
89 pte_t pte;
90 int ret = -ENOMEM;
91
92 for (address = start; address < start + size; address += PAGE_SIZE) {
93 pg_dir = pgd_offset_k(address);
94 if (pgd_none(*pg_dir)) {
95 pu_dir = vmem_pud_alloc();
96 if (!pu_dir)
97 goto out;
98 pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
99 }
100
101 pu_dir = pud_offset(pg_dir, address);
102 if (pud_none(*pu_dir)) {
103 pm_dir = vmem_pmd_alloc();
104 if (!pm_dir)
105 goto out;
106 pud_populate_kernel(&init_mm, pu_dir, pm_dir);
107 }
108
109 pte = mk_pte_phys(address, __pgprot(ro ? _PAGE_RO : 0));
110 pm_dir = pmd_offset(pu_dir, address);
111
112 #ifdef __s390x__
113 if (MACHINE_HAS_HPAGE && !(address & ~HPAGE_MASK) &&
114 (address + HPAGE_SIZE <= start + size) &&
115 (address >= HPAGE_SIZE)) {
116 pte_val(pte) |= _SEGMENT_ENTRY_LARGE;
117 pmd_val(*pm_dir) = pte_val(pte);
118 address += HPAGE_SIZE - PAGE_SIZE;
119 continue;
120 }
121 #endif
122 if (pmd_none(*pm_dir)) {
123 pt_dir = vmem_pte_alloc();
124 if (!pt_dir)
125 goto out;
126 pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
127 }
128
129 pt_dir = pte_offset_kernel(pm_dir, address);
130 *pt_dir = pte;
131 }
132 ret = 0;
133 out:
134 flush_tlb_kernel_range(start, start + size);
135 return ret;
136 }
137
138 /*
139 * Remove a physical memory range from the 1:1 mapping.
140 * Currently only invalidates page table entries.
141 */
vmem_remove_range(unsigned long start,unsigned long size)142 static void vmem_remove_range(unsigned long start, unsigned long size)
143 {
144 unsigned long address;
145 pgd_t *pg_dir;
146 pud_t *pu_dir;
147 pmd_t *pm_dir;
148 pte_t *pt_dir;
149 pte_t pte;
150
151 pte_val(pte) = _PAGE_TYPE_EMPTY;
152 for (address = start; address < start + size; address += PAGE_SIZE) {
153 pg_dir = pgd_offset_k(address);
154 pu_dir = pud_offset(pg_dir, address);
155 if (pud_none(*pu_dir))
156 continue;
157 pm_dir = pmd_offset(pu_dir, address);
158 if (pmd_none(*pm_dir))
159 continue;
160
161 if (pmd_huge(*pm_dir)) {
162 pmd_clear_kernel(pm_dir);
163 address += HPAGE_SIZE - PAGE_SIZE;
164 continue;
165 }
166
167 pt_dir = pte_offset_kernel(pm_dir, address);
168 *pt_dir = pte;
169 }
170 flush_tlb_kernel_range(start, start + size);
171 }
172
173 /*
174 * Add a backed mem_map array to the virtual mem_map array.
175 */
vmemmap_populate(struct page * start,unsigned long nr,int node)176 int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
177 {
178 unsigned long address, start_addr, end_addr;
179 pgd_t *pg_dir;
180 pud_t *pu_dir;
181 pmd_t *pm_dir;
182 pte_t *pt_dir;
183 pte_t pte;
184 int ret = -ENOMEM;
185
186 start_addr = (unsigned long) start;
187 end_addr = (unsigned long) (start + nr);
188
189 for (address = start_addr; address < end_addr; address += PAGE_SIZE) {
190 pg_dir = pgd_offset_k(address);
191 if (pgd_none(*pg_dir)) {
192 pu_dir = vmem_pud_alloc();
193 if (!pu_dir)
194 goto out;
195 pgd_populate_kernel(&init_mm, pg_dir, pu_dir);
196 }
197
198 pu_dir = pud_offset(pg_dir, address);
199 if (pud_none(*pu_dir)) {
200 pm_dir = vmem_pmd_alloc();
201 if (!pm_dir)
202 goto out;
203 pud_populate_kernel(&init_mm, pu_dir, pm_dir);
204 }
205
206 pm_dir = pmd_offset(pu_dir, address);
207 if (pmd_none(*pm_dir)) {
208 pt_dir = vmem_pte_alloc();
209 if (!pt_dir)
210 goto out;
211 pmd_populate_kernel(&init_mm, pm_dir, pt_dir);
212 }
213
214 pt_dir = pte_offset_kernel(pm_dir, address);
215 if (pte_none(*pt_dir)) {
216 unsigned long new_page;
217
218 new_page =__pa(vmem_alloc_pages(0));
219 if (!new_page)
220 goto out;
221 pte = pfn_pte(new_page >> PAGE_SHIFT, PAGE_KERNEL);
222 *pt_dir = pte;
223 }
224 }
225 memset(start, 0, nr * sizeof(struct page));
226 ret = 0;
227 out:
228 flush_tlb_kernel_range(start_addr, end_addr);
229 return ret;
230 }
231
232 /*
233 * Add memory segment to the segment list if it doesn't overlap with
234 * an already present segment.
235 */
insert_memory_segment(struct memory_segment * seg)236 static int insert_memory_segment(struct memory_segment *seg)
237 {
238 struct memory_segment *tmp;
239
240 if (seg->start + seg->size > VMEM_MAX_PHYS ||
241 seg->start + seg->size < seg->start)
242 return -ERANGE;
243
244 list_for_each_entry(tmp, &mem_segs, list) {
245 if (seg->start >= tmp->start + tmp->size)
246 continue;
247 if (seg->start + seg->size <= tmp->start)
248 continue;
249 return -ENOSPC;
250 }
251 list_add(&seg->list, &mem_segs);
252 return 0;
253 }
254
255 /*
256 * Remove memory segment from the segment list.
257 */
remove_memory_segment(struct memory_segment * seg)258 static void remove_memory_segment(struct memory_segment *seg)
259 {
260 list_del(&seg->list);
261 }
262
__remove_shared_memory(struct memory_segment * seg)263 static void __remove_shared_memory(struct memory_segment *seg)
264 {
265 remove_memory_segment(seg);
266 vmem_remove_range(seg->start, seg->size);
267 }
268
vmem_remove_mapping(unsigned long start,unsigned long size)269 int vmem_remove_mapping(unsigned long start, unsigned long size)
270 {
271 struct memory_segment *seg;
272 int ret;
273
274 mutex_lock(&vmem_mutex);
275
276 ret = -ENOENT;
277 list_for_each_entry(seg, &mem_segs, list) {
278 if (seg->start == start && seg->size == size)
279 break;
280 }
281
282 if (seg->start != start || seg->size != size)
283 goto out;
284
285 ret = 0;
286 __remove_shared_memory(seg);
287 kfree(seg);
288 out:
289 mutex_unlock(&vmem_mutex);
290 return ret;
291 }
292
vmem_add_mapping(unsigned long start,unsigned long size)293 int vmem_add_mapping(unsigned long start, unsigned long size)
294 {
295 struct memory_segment *seg;
296 int ret;
297
298 mutex_lock(&vmem_mutex);
299 ret = -ENOMEM;
300 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
301 if (!seg)
302 goto out;
303 seg->start = start;
304 seg->size = size;
305
306 ret = insert_memory_segment(seg);
307 if (ret)
308 goto out_free;
309
310 ret = vmem_add_mem(start, size, 0);
311 if (ret)
312 goto out_remove;
313 goto out;
314
315 out_remove:
316 __remove_shared_memory(seg);
317 out_free:
318 kfree(seg);
319 out:
320 mutex_unlock(&vmem_mutex);
321 return ret;
322 }
323
324 /*
325 * map whole physical memory to virtual memory (identity mapping)
326 * we reserve enough space in the vmalloc area for vmemmap to hotplug
327 * additional memory segments.
328 */
vmem_map_init(void)329 void __init vmem_map_init(void)
330 {
331 unsigned long ro_start, ro_end;
332 unsigned long start, end;
333 int i;
334
335 ro_start = ((unsigned long)&_stext) & PAGE_MASK;
336 ro_end = PFN_ALIGN((unsigned long)&_eshared);
337 for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
338 start = memory_chunk[i].addr;
339 end = memory_chunk[i].addr + memory_chunk[i].size;
340 if (start >= ro_end || end <= ro_start)
341 vmem_add_mem(start, end - start, 0);
342 else if (start >= ro_start && end <= ro_end)
343 vmem_add_mem(start, end - start, 1);
344 else if (start >= ro_start) {
345 vmem_add_mem(start, ro_end - start, 1);
346 vmem_add_mem(ro_end, end - ro_end, 0);
347 } else if (end < ro_end) {
348 vmem_add_mem(start, ro_start - start, 0);
349 vmem_add_mem(ro_start, end - ro_start, 1);
350 } else {
351 vmem_add_mem(start, ro_start - start, 0);
352 vmem_add_mem(ro_start, ro_end - ro_start, 1);
353 vmem_add_mem(ro_end, end - ro_end, 0);
354 }
355 }
356 }
357
358 /*
359 * Convert memory chunk array to a memory segment list so there is a single
360 * list that contains both r/w memory and shared memory segments.
361 */
vmem_convert_memory_chunk(void)362 static int __init vmem_convert_memory_chunk(void)
363 {
364 struct memory_segment *seg;
365 int i;
366
367 mutex_lock(&vmem_mutex);
368 for (i = 0; i < MEMORY_CHUNKS; i++) {
369 if (!memory_chunk[i].size)
370 continue;
371 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
372 if (!seg)
373 panic("Out of memory...\n");
374 seg->start = memory_chunk[i].addr;
375 seg->size = memory_chunk[i].size;
376 insert_memory_segment(seg);
377 }
378 mutex_unlock(&vmem_mutex);
379 return 0;
380 }
381
382 core_initcall(vmem_convert_memory_chunk);
383