1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2006 4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> 5 */ 6 7 #include <linux/bootmem.h> 8 #include <linux/pfn.h> 9 #include <linux/mm.h> 10 #include <linux/init.h> 11 #include <linux/list.h> 12 #include <linux/hugetlb.h> 13 #include <linux/slab.h> 14 #include <linux/memblock.h> 15 #include <asm/cacheflush.h> 16 #include <asm/pgalloc.h> 17 #include <asm/pgtable.h> 18 #include <asm/setup.h> 19 #include <asm/tlbflush.h> 20 #include <asm/sections.h> 21 #include <asm/set_memory.h> 22 23 static DEFINE_MUTEX(vmem_mutex); 24 25 struct memory_segment { 26 struct list_head list; 27 unsigned long start; 28 unsigned long size; 29 }; 30 31 static LIST_HEAD(mem_segs); 32 33 static void __ref *vmem_alloc_pages(unsigned int order) 34 { 35 unsigned long size = PAGE_SIZE << order; 36 37 if (slab_is_available()) 38 return (void *)__get_free_pages(GFP_KERNEL, order); 39 return (void *) memblock_alloc(size, size); 40 } 41 42 void *vmem_crst_alloc(unsigned long val) 43 { 44 unsigned long *table; 45 46 table = vmem_alloc_pages(CRST_ALLOC_ORDER); 47 if (table) 48 crst_table_init(table, val); 49 return table; 50 } 51 52 pte_t __ref *vmem_pte_alloc(void) 53 { 54 unsigned long size = PTRS_PER_PTE * sizeof(pte_t); 55 pte_t *pte; 56 57 if (slab_is_available()) 58 pte = (pte_t *) page_table_alloc(&init_mm); 59 else 60 pte = (pte_t *) memblock_alloc(size, size); 61 if (!pte) 62 return NULL; 63 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); 64 return pte; 65 } 66 67 /* 68 * Add a physical memory range to the 1:1 mapping. 69 */ 70 static int vmem_add_mem(unsigned long start, unsigned long size) 71 { 72 unsigned long pgt_prot, sgt_prot, r3_prot; 73 unsigned long pages4k, pages1m, pages2g; 74 unsigned long end = start + size; 75 unsigned long address = start; 76 pgd_t *pg_dir; 77 p4d_t *p4_dir; 78 pud_t *pu_dir; 79 pmd_t *pm_dir; 80 pte_t *pt_dir; 81 int ret = -ENOMEM; 82 83 pgt_prot = pgprot_val(PAGE_KERNEL); 84 sgt_prot = pgprot_val(SEGMENT_KERNEL); 85 r3_prot = pgprot_val(REGION3_KERNEL); 86 if (!MACHINE_HAS_NX) { 87 pgt_prot &= ~_PAGE_NOEXEC; 88 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; 89 r3_prot &= ~_REGION_ENTRY_NOEXEC; 90 } 91 pages4k = pages1m = pages2g = 0; 92 while (address < end) { 93 pg_dir = pgd_offset_k(address); 94 if (pgd_none(*pg_dir)) { 95 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 96 if (!p4_dir) 97 goto out; 98 pgd_populate(&init_mm, pg_dir, p4_dir); 99 } 100 p4_dir = p4d_offset(pg_dir, address); 101 if (p4d_none(*p4_dir)) { 102 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 103 if (!pu_dir) 104 goto out; 105 p4d_populate(&init_mm, p4_dir, pu_dir); 106 } 107 pu_dir = pud_offset(p4_dir, address); 108 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address && 109 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) && 110 !debug_pagealloc_enabled()) { 111 pud_val(*pu_dir) = address | r3_prot; 112 address += PUD_SIZE; 113 pages2g++; 114 continue; 115 } 116 if (pud_none(*pu_dir)) { 117 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 118 if (!pm_dir) 119 goto out; 120 pud_populate(&init_mm, pu_dir, pm_dir); 121 } 122 pm_dir = pmd_offset(pu_dir, address); 123 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address && 124 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) && 125 !debug_pagealloc_enabled()) { 126 pmd_val(*pm_dir) = address | sgt_prot; 127 address += PMD_SIZE; 128 pages1m++; 129 continue; 130 } 131 if (pmd_none(*pm_dir)) { 132 pt_dir = vmem_pte_alloc(); 133 if (!pt_dir) 134 goto out; 135 pmd_populate(&init_mm, pm_dir, pt_dir); 136 } 137 138 pt_dir = pte_offset_kernel(pm_dir, address); 139 pte_val(*pt_dir) = address | pgt_prot; 140 address += PAGE_SIZE; 141 pages4k++; 142 } 143 ret = 0; 144 out: 145 update_page_count(PG_DIRECT_MAP_4K, pages4k); 146 update_page_count(PG_DIRECT_MAP_1M, pages1m); 147 update_page_count(PG_DIRECT_MAP_2G, pages2g); 148 return ret; 149 } 150 151 /* 152 * Remove a physical memory range from the 1:1 mapping. 153 * Currently only invalidates page table entries. 154 */ 155 static void vmem_remove_range(unsigned long start, unsigned long size) 156 { 157 unsigned long pages4k, pages1m, pages2g; 158 unsigned long end = start + size; 159 unsigned long address = start; 160 pgd_t *pg_dir; 161 p4d_t *p4_dir; 162 pud_t *pu_dir; 163 pmd_t *pm_dir; 164 pte_t *pt_dir; 165 166 pages4k = pages1m = pages2g = 0; 167 while (address < end) { 168 pg_dir = pgd_offset_k(address); 169 if (pgd_none(*pg_dir)) { 170 address += PGDIR_SIZE; 171 continue; 172 } 173 p4_dir = p4d_offset(pg_dir, address); 174 if (p4d_none(*p4_dir)) { 175 address += P4D_SIZE; 176 continue; 177 } 178 pu_dir = pud_offset(p4_dir, address); 179 if (pud_none(*pu_dir)) { 180 address += PUD_SIZE; 181 continue; 182 } 183 if (pud_large(*pu_dir)) { 184 pud_clear(pu_dir); 185 address += PUD_SIZE; 186 pages2g++; 187 continue; 188 } 189 pm_dir = pmd_offset(pu_dir, address); 190 if (pmd_none(*pm_dir)) { 191 address += PMD_SIZE; 192 continue; 193 } 194 if (pmd_large(*pm_dir)) { 195 pmd_clear(pm_dir); 196 address += PMD_SIZE; 197 pages1m++; 198 continue; 199 } 200 pt_dir = pte_offset_kernel(pm_dir, address); 201 pte_clear(&init_mm, address, pt_dir); 202 address += PAGE_SIZE; 203 pages4k++; 204 } 205 flush_tlb_kernel_range(start, end); 206 update_page_count(PG_DIRECT_MAP_4K, -pages4k); 207 update_page_count(PG_DIRECT_MAP_1M, -pages1m); 208 update_page_count(PG_DIRECT_MAP_2G, -pages2g); 209 } 210 211 /* 212 * Add a backed mem_map array to the virtual mem_map array. 213 */ 214 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) 215 { 216 unsigned long pgt_prot, sgt_prot; 217 unsigned long address = start; 218 pgd_t *pg_dir; 219 p4d_t *p4_dir; 220 pud_t *pu_dir; 221 pmd_t *pm_dir; 222 pte_t *pt_dir; 223 int ret = -ENOMEM; 224 225 pgt_prot = pgprot_val(PAGE_KERNEL); 226 sgt_prot = pgprot_val(SEGMENT_KERNEL); 227 if (!MACHINE_HAS_NX) { 228 pgt_prot &= ~_PAGE_NOEXEC; 229 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; 230 } 231 for (address = start; address < end;) { 232 pg_dir = pgd_offset_k(address); 233 if (pgd_none(*pg_dir)) { 234 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 235 if (!p4_dir) 236 goto out; 237 pgd_populate(&init_mm, pg_dir, p4_dir); 238 } 239 240 p4_dir = p4d_offset(pg_dir, address); 241 if (p4d_none(*p4_dir)) { 242 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 243 if (!pu_dir) 244 goto out; 245 p4d_populate(&init_mm, p4_dir, pu_dir); 246 } 247 248 pu_dir = pud_offset(p4_dir, address); 249 if (pud_none(*pu_dir)) { 250 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 251 if (!pm_dir) 252 goto out; 253 pud_populate(&init_mm, pu_dir, pm_dir); 254 } 255 256 pm_dir = pmd_offset(pu_dir, address); 257 if (pmd_none(*pm_dir)) { 258 /* Use 1MB frames for vmemmap if available. We always 259 * use large frames even if they are only partially 260 * used. 261 * Otherwise we would have also page tables since 262 * vmemmap_populate gets called for each section 263 * separately. */ 264 if (MACHINE_HAS_EDAT1) { 265 void *new_page; 266 267 new_page = vmemmap_alloc_block(PMD_SIZE, node); 268 if (!new_page) 269 goto out; 270 pmd_val(*pm_dir) = __pa(new_page) | sgt_prot; 271 address = (address + PMD_SIZE) & PMD_MASK; 272 continue; 273 } 274 pt_dir = vmem_pte_alloc(); 275 if (!pt_dir) 276 goto out; 277 pmd_populate(&init_mm, pm_dir, pt_dir); 278 } else if (pmd_large(*pm_dir)) { 279 address = (address + PMD_SIZE) & PMD_MASK; 280 continue; 281 } 282 283 pt_dir = pte_offset_kernel(pm_dir, address); 284 if (pte_none(*pt_dir)) { 285 void *new_page; 286 287 new_page = vmemmap_alloc_block(PAGE_SIZE, node); 288 if (!new_page) 289 goto out; 290 pte_val(*pt_dir) = __pa(new_page) | pgt_prot; 291 } 292 address += PAGE_SIZE; 293 } 294 ret = 0; 295 out: 296 return ret; 297 } 298 299 void vmemmap_free(unsigned long start, unsigned long end) 300 { 301 } 302 303 /* 304 * Add memory segment to the segment list if it doesn't overlap with 305 * an already present segment. 306 */ 307 static int insert_memory_segment(struct memory_segment *seg) 308 { 309 struct memory_segment *tmp; 310 311 if (seg->start + seg->size > VMEM_MAX_PHYS || 312 seg->start + seg->size < seg->start) 313 return -ERANGE; 314 315 list_for_each_entry(tmp, &mem_segs, list) { 316 if (seg->start >= tmp->start + tmp->size) 317 continue; 318 if (seg->start + seg->size <= tmp->start) 319 continue; 320 return -ENOSPC; 321 } 322 list_add(&seg->list, &mem_segs); 323 return 0; 324 } 325 326 /* 327 * Remove memory segment from the segment list. 328 */ 329 static void remove_memory_segment(struct memory_segment *seg) 330 { 331 list_del(&seg->list); 332 } 333 334 static void __remove_shared_memory(struct memory_segment *seg) 335 { 336 remove_memory_segment(seg); 337 vmem_remove_range(seg->start, seg->size); 338 } 339 340 int vmem_remove_mapping(unsigned long start, unsigned long size) 341 { 342 struct memory_segment *seg; 343 int ret; 344 345 mutex_lock(&vmem_mutex); 346 347 ret = -ENOENT; 348 list_for_each_entry(seg, &mem_segs, list) { 349 if (seg->start == start && seg->size == size) 350 break; 351 } 352 353 if (seg->start != start || seg->size != size) 354 goto out; 355 356 ret = 0; 357 __remove_shared_memory(seg); 358 kfree(seg); 359 out: 360 mutex_unlock(&vmem_mutex); 361 return ret; 362 } 363 364 int vmem_add_mapping(unsigned long start, unsigned long size) 365 { 366 struct memory_segment *seg; 367 int ret; 368 369 mutex_lock(&vmem_mutex); 370 ret = -ENOMEM; 371 seg = kzalloc(sizeof(*seg), GFP_KERNEL); 372 if (!seg) 373 goto out; 374 seg->start = start; 375 seg->size = size; 376 377 ret = insert_memory_segment(seg); 378 if (ret) 379 goto out_free; 380 381 ret = vmem_add_mem(start, size); 382 if (ret) 383 goto out_remove; 384 goto out; 385 386 out_remove: 387 __remove_shared_memory(seg); 388 out_free: 389 kfree(seg); 390 out: 391 mutex_unlock(&vmem_mutex); 392 return ret; 393 } 394 395 /* 396 * map whole physical memory to virtual memory (identity mapping) 397 * we reserve enough space in the vmalloc area for vmemmap to hotplug 398 * additional memory segments. 399 */ 400 void __init vmem_map_init(void) 401 { 402 struct memblock_region *reg; 403 404 for_each_memblock(memory, reg) 405 vmem_add_mem(reg->base, reg->size); 406 __set_memory((unsigned long)_stext, 407 (unsigned long)(_etext - _stext) >> PAGE_SHIFT, 408 SET_MEMORY_RO | SET_MEMORY_X); 409 __set_memory((unsigned long)_etext, 410 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT, 411 SET_MEMORY_RO); 412 __set_memory((unsigned long)_sinittext, 413 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT, 414 SET_MEMORY_RO | SET_MEMORY_X); 415 pr_info("Write protected kernel read-only data: %luk\n", 416 (unsigned long)(__end_rodata - _stext) >> 10); 417 } 418 419 /* 420 * Convert memblock.memory to a memory segment list so there is a single 421 * list that contains all memory segments. 422 */ 423 static int __init vmem_convert_memory_chunk(void) 424 { 425 struct memblock_region *reg; 426 struct memory_segment *seg; 427 428 mutex_lock(&vmem_mutex); 429 for_each_memblock(memory, reg) { 430 seg = kzalloc(sizeof(*seg), GFP_KERNEL); 431 if (!seg) 432 panic("Out of memory...\n"); 433 seg->start = reg->base; 434 seg->size = reg->size; 435 insert_memory_segment(seg); 436 } 437 mutex_unlock(&vmem_mutex); 438 return 0; 439 } 440 441 core_initcall(vmem_convert_memory_chunk); 442