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/memblock.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 <asm/cacheflush.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 #include <asm/set_memory.h> 21 22 static DEFINE_MUTEX(vmem_mutex); 23 24 struct memory_segment { 25 struct list_head list; 26 unsigned long start; 27 unsigned long size; 28 }; 29 30 static LIST_HEAD(mem_segs); 31 32 static void __ref *vmem_alloc_pages(unsigned int order) 33 { 34 unsigned long size = PAGE_SIZE << order; 35 36 if (slab_is_available()) 37 return (void *)__get_free_pages(GFP_KERNEL, order); 38 return (void *) memblock_phys_alloc(size, size); 39 } 40 41 void *vmem_crst_alloc(unsigned long val) 42 { 43 unsigned long *table; 44 45 table = vmem_alloc_pages(CRST_ALLOC_ORDER); 46 if (table) 47 crst_table_init(table, val); 48 return table; 49 } 50 51 pte_t __ref *vmem_pte_alloc(void) 52 { 53 unsigned long size = PTRS_PER_PTE * sizeof(pte_t); 54 pte_t *pte; 55 56 if (slab_is_available()) 57 pte = (pte_t *) page_table_alloc(&init_mm); 58 else 59 pte = (pte_t *) memblock_phys_alloc(size, size); 60 if (!pte) 61 return NULL; 62 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); 63 return pte; 64 } 65 66 /* 67 * Add a physical memory range to the 1:1 mapping. 68 */ 69 static int vmem_add_mem(unsigned long start, unsigned long size) 70 { 71 unsigned long pgt_prot, sgt_prot, r3_prot; 72 unsigned long pages4k, pages1m, pages2g; 73 unsigned long end = start + size; 74 unsigned long address = start; 75 pgd_t *pg_dir; 76 p4d_t *p4_dir; 77 pud_t *pu_dir; 78 pmd_t *pm_dir; 79 pte_t *pt_dir; 80 int ret = -ENOMEM; 81 82 pgt_prot = pgprot_val(PAGE_KERNEL); 83 sgt_prot = pgprot_val(SEGMENT_KERNEL); 84 r3_prot = pgprot_val(REGION3_KERNEL); 85 if (!MACHINE_HAS_NX) { 86 pgt_prot &= ~_PAGE_NOEXEC; 87 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; 88 r3_prot &= ~_REGION_ENTRY_NOEXEC; 89 } 90 pages4k = pages1m = pages2g = 0; 91 while (address < end) { 92 pg_dir = pgd_offset_k(address); 93 if (pgd_none(*pg_dir)) { 94 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 95 if (!p4_dir) 96 goto out; 97 pgd_populate(&init_mm, pg_dir, p4_dir); 98 } 99 p4_dir = p4d_offset(pg_dir, address); 100 if (p4d_none(*p4_dir)) { 101 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 102 if (!pu_dir) 103 goto out; 104 p4d_populate(&init_mm, p4_dir, pu_dir); 105 } 106 pu_dir = pud_offset(p4_dir, address); 107 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address && 108 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) && 109 !debug_pagealloc_enabled()) { 110 pud_val(*pu_dir) = address | r3_prot; 111 address += PUD_SIZE; 112 pages2g++; 113 continue; 114 } 115 if (pud_none(*pu_dir)) { 116 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 117 if (!pm_dir) 118 goto out; 119 pud_populate(&init_mm, pu_dir, pm_dir); 120 } 121 pm_dir = pmd_offset(pu_dir, address); 122 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address && 123 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) && 124 !debug_pagealloc_enabled()) { 125 pmd_val(*pm_dir) = address | sgt_prot; 126 address += PMD_SIZE; 127 pages1m++; 128 continue; 129 } 130 if (pmd_none(*pm_dir)) { 131 pt_dir = vmem_pte_alloc(); 132 if (!pt_dir) 133 goto out; 134 pmd_populate(&init_mm, pm_dir, pt_dir); 135 } 136 137 pt_dir = pte_offset_kernel(pm_dir, address); 138 pte_val(*pt_dir) = address | pgt_prot; 139 address += PAGE_SIZE; 140 pages4k++; 141 } 142 ret = 0; 143 out: 144 update_page_count(PG_DIRECT_MAP_4K, pages4k); 145 update_page_count(PG_DIRECT_MAP_1M, pages1m); 146 update_page_count(PG_DIRECT_MAP_2G, pages2g); 147 return ret; 148 } 149 150 /* 151 * Remove a physical memory range from the 1:1 mapping. 152 * Currently only invalidates page table entries. 153 */ 154 static void vmem_remove_range(unsigned long start, unsigned long size) 155 { 156 unsigned long pages4k, pages1m, pages2g; 157 unsigned long end = start + size; 158 unsigned long address = start; 159 pgd_t *pg_dir; 160 p4d_t *p4_dir; 161 pud_t *pu_dir; 162 pmd_t *pm_dir; 163 pte_t *pt_dir; 164 165 pages4k = pages1m = pages2g = 0; 166 while (address < end) { 167 pg_dir = pgd_offset_k(address); 168 if (pgd_none(*pg_dir)) { 169 address += PGDIR_SIZE; 170 continue; 171 } 172 p4_dir = p4d_offset(pg_dir, address); 173 if (p4d_none(*p4_dir)) { 174 address += P4D_SIZE; 175 continue; 176 } 177 pu_dir = pud_offset(p4_dir, address); 178 if (pud_none(*pu_dir)) { 179 address += PUD_SIZE; 180 continue; 181 } 182 if (pud_large(*pu_dir)) { 183 pud_clear(pu_dir); 184 address += PUD_SIZE; 185 pages2g++; 186 continue; 187 } 188 pm_dir = pmd_offset(pu_dir, address); 189 if (pmd_none(*pm_dir)) { 190 address += PMD_SIZE; 191 continue; 192 } 193 if (pmd_large(*pm_dir)) { 194 pmd_clear(pm_dir); 195 address += PMD_SIZE; 196 pages1m++; 197 continue; 198 } 199 pt_dir = pte_offset_kernel(pm_dir, address); 200 pte_clear(&init_mm, address, pt_dir); 201 address += PAGE_SIZE; 202 pages4k++; 203 } 204 flush_tlb_kernel_range(start, end); 205 update_page_count(PG_DIRECT_MAP_4K, -pages4k); 206 update_page_count(PG_DIRECT_MAP_1M, -pages1m); 207 update_page_count(PG_DIRECT_MAP_2G, -pages2g); 208 } 209 210 /* 211 * Add a backed mem_map array to the virtual mem_map array. 212 */ 213 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 214 struct vmem_altmap *altmap) 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 struct vmem_altmap *altmap) 301 { 302 } 303 304 /* 305 * Add memory segment to the segment list if it doesn't overlap with 306 * an already present segment. 307 */ 308 static int insert_memory_segment(struct memory_segment *seg) 309 { 310 struct memory_segment *tmp; 311 312 if (seg->start + seg->size > VMEM_MAX_PHYS || 313 seg->start + seg->size < seg->start) 314 return -ERANGE; 315 316 list_for_each_entry(tmp, &mem_segs, list) { 317 if (seg->start >= tmp->start + tmp->size) 318 continue; 319 if (seg->start + seg->size <= tmp->start) 320 continue; 321 return -ENOSPC; 322 } 323 list_add(&seg->list, &mem_segs); 324 return 0; 325 } 326 327 /* 328 * Remove memory segment from the segment list. 329 */ 330 static void remove_memory_segment(struct memory_segment *seg) 331 { 332 list_del(&seg->list); 333 } 334 335 static void __remove_shared_memory(struct memory_segment *seg) 336 { 337 remove_memory_segment(seg); 338 vmem_remove_range(seg->start, seg->size); 339 } 340 341 int vmem_remove_mapping(unsigned long start, unsigned long size) 342 { 343 struct memory_segment *seg; 344 int ret; 345 346 mutex_lock(&vmem_mutex); 347 348 ret = -ENOENT; 349 list_for_each_entry(seg, &mem_segs, list) { 350 if (seg->start == start && seg->size == size) 351 break; 352 } 353 354 if (seg->start != start || seg->size != size) 355 goto out; 356 357 ret = 0; 358 __remove_shared_memory(seg); 359 kfree(seg); 360 out: 361 mutex_unlock(&vmem_mutex); 362 return ret; 363 } 364 365 int vmem_add_mapping(unsigned long start, unsigned long size) 366 { 367 struct memory_segment *seg; 368 int ret; 369 370 mutex_lock(&vmem_mutex); 371 ret = -ENOMEM; 372 seg = kzalloc(sizeof(*seg), GFP_KERNEL); 373 if (!seg) 374 goto out; 375 seg->start = start; 376 seg->size = size; 377 378 ret = insert_memory_segment(seg); 379 if (ret) 380 goto out_free; 381 382 ret = vmem_add_mem(start, size); 383 if (ret) 384 goto out_remove; 385 goto out; 386 387 out_remove: 388 __remove_shared_memory(seg); 389 out_free: 390 kfree(seg); 391 out: 392 mutex_unlock(&vmem_mutex); 393 return ret; 394 } 395 396 /* 397 * map whole physical memory to virtual memory (identity mapping) 398 * we reserve enough space in the vmalloc area for vmemmap to hotplug 399 * additional memory segments. 400 */ 401 void __init vmem_map_init(void) 402 { 403 struct memblock_region *reg; 404 405 for_each_memblock(memory, reg) 406 vmem_add_mem(reg->base, reg->size); 407 __set_memory((unsigned long)_stext, 408 (unsigned long)(_etext - _stext) >> PAGE_SHIFT, 409 SET_MEMORY_RO | SET_MEMORY_X); 410 __set_memory((unsigned long)_etext, 411 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT, 412 SET_MEMORY_RO); 413 __set_memory((unsigned long)_sinittext, 414 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT, 415 SET_MEMORY_RO | SET_MEMORY_X); 416 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT, 417 SET_MEMORY_RO | SET_MEMORY_X); 418 419 /* we need lowcore executable for our LPSWE instructions */ 420 set_memory_x(0, 1); 421 422 pr_info("Write protected kernel read-only data: %luk\n", 423 (unsigned long)(__end_rodata - _stext) >> 10); 424 } 425 426 /* 427 * Convert memblock.memory to a memory segment list so there is a single 428 * list that contains all memory segments. 429 */ 430 static int __init vmem_convert_memory_chunk(void) 431 { 432 struct memblock_region *reg; 433 struct memory_segment *seg; 434 435 mutex_lock(&vmem_mutex); 436 for_each_memblock(memory, reg) { 437 seg = kzalloc(sizeof(*seg), GFP_KERNEL); 438 if (!seg) 439 panic("Out of memory...\n"); 440 seg->start = reg->base; 441 seg->size = reg->size; 442 insert_memory_segment(seg); 443 } 444 mutex_unlock(&vmem_mutex); 445 return 0; 446 } 447 448 core_initcall(vmem_convert_memory_chunk); 449