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Linux/arch/s390/mm/vmem.c

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  1 /*
  2  *    Copyright IBM Corp. 2006
  3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
  4  */
  5 
  6 #include <linux/bootmem.h>
  7 #include <linux/pfn.h>
  8 #include <linux/mm.h>
  9 #include <linux/module.h>
 10 #include <linux/list.h>
 11 #include <linux/hugetlb.h>
 12 #include <linux/slab.h>
 13 #include <asm/pgalloc.h>
 14 #include <asm/pgtable.h>
 15 #include <asm/setup.h>
 16 #include <asm/tlbflush.h>
 17 #include <asm/sections.h>
 18 
 19 static DEFINE_MUTEX(vmem_mutex);
 20 
 21 struct memory_segment {
 22         struct list_head list;
 23         unsigned long start;
 24         unsigned long size;
 25 };
 26 
 27 static LIST_HEAD(mem_segs);
 28 
 29 static void __ref *vmem_alloc_pages(unsigned int order)
 30 {
 31         if (slab_is_available())
 32                 return (void *)__get_free_pages(GFP_KERNEL, order);
 33         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
 34 }
 35 
 36 static inline pud_t *vmem_pud_alloc(void)
 37 {
 38         pud_t *pud = NULL;
 39 
 40 #ifdef CONFIG_64BIT
 41         pud = vmem_alloc_pages(2);
 42         if (!pud)
 43                 return NULL;
 44         clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
 45 #endif
 46         return pud;
 47 }
 48 
 49 static inline pmd_t *vmem_pmd_alloc(void)
 50 {
 51         pmd_t *pmd = NULL;
 52 
 53 #ifdef CONFIG_64BIT
 54         pmd = vmem_alloc_pages(2);
 55         if (!pmd)
 56                 return NULL;
 57         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
 58 #endif
 59         return pmd;
 60 }
 61 
 62 static pte_t __ref *vmem_pte_alloc(unsigned long address)
 63 {
 64         pte_t *pte;
 65 
 66         if (slab_is_available())
 67                 pte = (pte_t *) page_table_alloc(&init_mm, address);
 68         else
 69                 pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
 70         if (!pte)
 71                 return NULL;
 72         clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY,
 73                     PTRS_PER_PTE * sizeof(pte_t));
 74         return pte;
 75 }
 76 
 77 /*
 78  * Add a physical memory range to the 1:1 mapping.
 79  */
 80 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
 81 {
 82         unsigned long end = start + size;
 83         unsigned long address = start;
 84         pgd_t *pg_dir;
 85         pud_t *pu_dir;
 86         pmd_t *pm_dir;
 87         pte_t *pt_dir;
 88         int ret = -ENOMEM;
 89 
 90         while (address < end) {
 91                 pg_dir = pgd_offset_k(address);
 92                 if (pgd_none(*pg_dir)) {
 93                         pu_dir = vmem_pud_alloc();
 94                         if (!pu_dir)
 95                                 goto out;
 96                         pgd_populate(&init_mm, pg_dir, pu_dir);
 97                 }
 98                 pu_dir = pud_offset(pg_dir, address);
 99 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
100                 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
101                     !(address & ~PUD_MASK) && (address + PUD_SIZE <= end)) {
102                         pud_val(*pu_dir) = __pa(address) |
103                                 _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE |
104                                 (ro ? _REGION_ENTRY_RO : 0);
105                         address += PUD_SIZE;
106                         continue;
107                 }
108 #endif
109                 if (pud_none(*pu_dir)) {
110                         pm_dir = vmem_pmd_alloc();
111                         if (!pm_dir)
112                                 goto out;
113                         pud_populate(&init_mm, pu_dir, pm_dir);
114                 }
115                 pm_dir = pmd_offset(pu_dir, address);
116 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
117                 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
118                     !(address & ~PMD_MASK) && (address + PMD_SIZE <= end)) {
119                         pmd_val(*pm_dir) = __pa(address) |
120                                 _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
121                                 (ro ? _SEGMENT_ENTRY_RO : 0);
122                         address += PMD_SIZE;
123                         continue;
124                 }
125 #endif
126                 if (pmd_none(*pm_dir)) {
127                         pt_dir = vmem_pte_alloc(address);
128                         if (!pt_dir)
129                                 goto out;
130                         pmd_populate(&init_mm, pm_dir, pt_dir);
131                 }
132 
133                 pt_dir = pte_offset_kernel(pm_dir, address);
134                 pte_val(*pt_dir) = __pa(address) | (ro ? _PAGE_RO : 0);
135                 address += PAGE_SIZE;
136         }
137         ret = 0;
138 out:
139         flush_tlb_kernel_range(start, end);
140         return ret;
141 }
142 
143 /*
144  * Remove a physical memory range from the 1:1 mapping.
145  * Currently only invalidates page table entries.
146  */
147 static void vmem_remove_range(unsigned long start, unsigned long size)
148 {
149         unsigned long end = start + size;
150         unsigned long address = start;
151         pgd_t *pg_dir;
152         pud_t *pu_dir;
153         pmd_t *pm_dir;
154         pte_t *pt_dir;
155         pte_t  pte;
156 
157         pte_val(pte) = _PAGE_TYPE_EMPTY;
158         while (address < end) {
159                 pg_dir = pgd_offset_k(address);
160                 if (pgd_none(*pg_dir)) {
161                         address += PGDIR_SIZE;
162                         continue;
163                 }
164                 pu_dir = pud_offset(pg_dir, address);
165                 if (pud_none(*pu_dir)) {
166                         address += PUD_SIZE;
167                         continue;
168                 }
169                 if (pud_large(*pu_dir)) {
170                         pud_clear(pu_dir);
171                         address += PUD_SIZE;
172                         continue;
173                 }
174                 pm_dir = pmd_offset(pu_dir, address);
175                 if (pmd_none(*pm_dir)) {
176                         address += PMD_SIZE;
177                         continue;
178                 }
179                 if (pmd_large(*pm_dir)) {
180                         pmd_clear(pm_dir);
181                         address += PMD_SIZE;
182                         continue;
183                 }
184                 pt_dir = pte_offset_kernel(pm_dir, address);
185                 *pt_dir = pte;
186                 address += PAGE_SIZE;
187         }
188         flush_tlb_kernel_range(start, end);
189 }
190 
191 /*
192  * Add a backed mem_map array to the virtual mem_map array.
193  */
194 int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
195 {
196         unsigned long address, start_addr, end_addr;
197         pgd_t *pg_dir;
198         pud_t *pu_dir;
199         pmd_t *pm_dir;
200         pte_t *pt_dir;
201         int ret = -ENOMEM;
202 
203         start_addr = (unsigned long) start;
204         end_addr = (unsigned long) (start + nr);
205 
206         for (address = start_addr; address < end_addr;) {
207                 pg_dir = pgd_offset_k(address);
208                 if (pgd_none(*pg_dir)) {
209                         pu_dir = vmem_pud_alloc();
210                         if (!pu_dir)
211                                 goto out;
212                         pgd_populate(&init_mm, pg_dir, pu_dir);
213                 }
214 
215                 pu_dir = pud_offset(pg_dir, address);
216                 if (pud_none(*pu_dir)) {
217                         pm_dir = vmem_pmd_alloc();
218                         if (!pm_dir)
219                                 goto out;
220                         pud_populate(&init_mm, pu_dir, pm_dir);
221                 }
222 
223                 pm_dir = pmd_offset(pu_dir, address);
224                 if (pmd_none(*pm_dir)) {
225 #ifdef CONFIG_64BIT
226                         /* Use 1MB frames for vmemmap if available. We always
227                          * use large frames even if they are only partially
228                          * used.
229                          * Otherwise we would have also page tables since
230                          * vmemmap_populate gets called for each section
231                          * separately. */
232                         if (MACHINE_HAS_EDAT1) {
233                                 void *new_page;
234 
235                                 new_page = vmemmap_alloc_block(PMD_SIZE, node);
236                                 if (!new_page)
237                                         goto out;
238                                 pmd_val(*pm_dir) = __pa(new_page) |
239                                         _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
240                                         _SEGMENT_ENTRY_CO;
241                                 address = (address + PMD_SIZE) & PMD_MASK;
242                                 continue;
243                         }
244 #endif
245                         pt_dir = vmem_pte_alloc(address);
246                         if (!pt_dir)
247                                 goto out;
248                         pmd_populate(&init_mm, pm_dir, pt_dir);
249                 } else if (pmd_large(*pm_dir)) {
250                         address = (address + PMD_SIZE) & PMD_MASK;
251                         continue;
252                 }
253 
254                 pt_dir = pte_offset_kernel(pm_dir, address);
255                 if (pte_none(*pt_dir)) {
256                         unsigned long new_page;
257 
258                         new_page =__pa(vmem_alloc_pages(0));
259                         if (!new_page)
260                                 goto out;
261                         pte_val(*pt_dir) = __pa(new_page);
262                 }
263                 address += PAGE_SIZE;
264         }
265         memset(start, 0, nr * sizeof(struct page));
266         ret = 0;
267 out:
268         flush_tlb_kernel_range(start_addr, end_addr);
269         return ret;
270 }
271 
272 void vmemmap_free(struct page *memmap, unsigned long nr_pages)
273 {
274 }
275 
276 /*
277  * Add memory segment to the segment list if it doesn't overlap with
278  * an already present segment.
279  */
280 static int insert_memory_segment(struct memory_segment *seg)
281 {
282         struct memory_segment *tmp;
283 
284         if (seg->start + seg->size > VMEM_MAX_PHYS ||
285             seg->start + seg->size < seg->start)
286                 return -ERANGE;
287 
288         list_for_each_entry(tmp, &mem_segs, list) {
289                 if (seg->start >= tmp->start + tmp->size)
290                         continue;
291                 if (seg->start + seg->size <= tmp->start)
292                         continue;
293                 return -ENOSPC;
294         }
295         list_add(&seg->list, &mem_segs);
296         return 0;
297 }
298 
299 /*
300  * Remove memory segment from the segment list.
301  */
302 static void remove_memory_segment(struct memory_segment *seg)
303 {
304         list_del(&seg->list);
305 }
306 
307 static void __remove_shared_memory(struct memory_segment *seg)
308 {
309         remove_memory_segment(seg);
310         vmem_remove_range(seg->start, seg->size);
311 }
312 
313 int vmem_remove_mapping(unsigned long start, unsigned long size)
314 {
315         struct memory_segment *seg;
316         int ret;
317 
318         mutex_lock(&vmem_mutex);
319 
320         ret = -ENOENT;
321         list_for_each_entry(seg, &mem_segs, list) {
322                 if (seg->start == start && seg->size == size)
323                         break;
324         }
325 
326         if (seg->start != start || seg->size != size)
327                 goto out;
328 
329         ret = 0;
330         __remove_shared_memory(seg);
331         kfree(seg);
332 out:
333         mutex_unlock(&vmem_mutex);
334         return ret;
335 }
336 
337 int vmem_add_mapping(unsigned long start, unsigned long size)
338 {
339         struct memory_segment *seg;
340         int ret;
341 
342         mutex_lock(&vmem_mutex);
343         ret = -ENOMEM;
344         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
345         if (!seg)
346                 goto out;
347         seg->start = start;
348         seg->size = size;
349 
350         ret = insert_memory_segment(seg);
351         if (ret)
352                 goto out_free;
353 
354         ret = vmem_add_mem(start, size, 0);
355         if (ret)
356                 goto out_remove;
357         goto out;
358 
359 out_remove:
360         __remove_shared_memory(seg);
361 out_free:
362         kfree(seg);
363 out:
364         mutex_unlock(&vmem_mutex);
365         return ret;
366 }
367 
368 /*
369  * map whole physical memory to virtual memory (identity mapping)
370  * we reserve enough space in the vmalloc area for vmemmap to hotplug
371  * additional memory segments.
372  */
373 void __init vmem_map_init(void)
374 {
375         unsigned long ro_start, ro_end;
376         unsigned long start, end;
377         int i;
378 
379         ro_start = PFN_ALIGN((unsigned long)&_stext);
380         ro_end = (unsigned long)&_eshared & PAGE_MASK;
381         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
382                 if (memory_chunk[i].type == CHUNK_CRASHK ||
383                     memory_chunk[i].type == CHUNK_OLDMEM)
384                         continue;
385                 start = memory_chunk[i].addr;
386                 end = memory_chunk[i].addr + memory_chunk[i].size;
387                 if (start >= ro_end || end <= ro_start)
388                         vmem_add_mem(start, end - start, 0);
389                 else if (start >= ro_start && end <= ro_end)
390                         vmem_add_mem(start, end - start, 1);
391                 else if (start >= ro_start) {
392                         vmem_add_mem(start, ro_end - start, 1);
393                         vmem_add_mem(ro_end, end - ro_end, 0);
394                 } else if (end < ro_end) {
395                         vmem_add_mem(start, ro_start - start, 0);
396                         vmem_add_mem(ro_start, end - ro_start, 1);
397                 } else {
398                         vmem_add_mem(start, ro_start - start, 0);
399                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
400                         vmem_add_mem(ro_end, end - ro_end, 0);
401                 }
402         }
403 }
404 
405 /*
406  * Convert memory chunk array to a memory segment list so there is a single
407  * list that contains both r/w memory and shared memory segments.
408  */
409 static int __init vmem_convert_memory_chunk(void)
410 {
411         struct memory_segment *seg;
412         int i;
413 
414         mutex_lock(&vmem_mutex);
415         for (i = 0; i < MEMORY_CHUNKS; i++) {
416                 if (!memory_chunk[i].size)
417                         continue;
418                 if (memory_chunk[i].type == CHUNK_CRASHK ||
419                     memory_chunk[i].type == CHUNK_OLDMEM)
420                         continue;
421                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
422                 if (!seg)
423                         panic("Out of memory...\n");
424                 seg->start = memory_chunk[i].addr;
425                 seg->size = memory_chunk[i].size;
426                 insert_memory_segment(seg);
427         }
428         mutex_unlock(&vmem_mutex);
429         return 0;
430 }
431 
432 core_initcall(vmem_convert_memory_chunk);
433 

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