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/setup.h> 17 #include <asm/tlbflush.h> 18 #include <asm/sections.h> 19 #include <asm/set_memory.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 31 static void __ref *vmem_alloc_pages(unsigned int order) 32 { 33 unsigned long size = PAGE_SIZE << order; 34 35 if (slab_is_available()) 36 return (void *)__get_free_pages(GFP_KERNEL, order); 37 return (void *) memblock_phys_alloc(size, size); 38 } 39 40 void *vmem_crst_alloc(unsigned long val) 41 { 42 unsigned long *table; 43 44 table = vmem_alloc_pages(CRST_ALLOC_ORDER); 45 if (table) 46 crst_table_init(table, val); 47 return table; 48 } 49 50 pte_t __ref *vmem_pte_alloc(void) 51 { 52 unsigned long size = PTRS_PER_PTE * sizeof(pte_t); 53 pte_t *pte; 54 55 if (slab_is_available()) 56 pte = (pte_t *) page_table_alloc(&init_mm); 57 else 58 pte = (pte_t *) memblock_phys_alloc(size, size); 59 if (!pte) 60 return NULL; 61 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); 62 return pte; 63 } 64 65 /* 66 * Add a physical memory range to the 1:1 mapping. 67 */ 68 static int vmem_add_mem(unsigned long start, unsigned long size) 69 { 70 unsigned long pgt_prot, sgt_prot, r3_prot; 71 unsigned long pages4k, pages1m, pages2g; 72 unsigned long end = start + size; 73 unsigned long address = start; 74 pgd_t *pg_dir; 75 p4d_t *p4_dir; 76 pud_t *pu_dir; 77 pmd_t *pm_dir; 78 pte_t *pt_dir; 79 int ret = -ENOMEM; 80 81 pgt_prot = pgprot_val(PAGE_KERNEL); 82 sgt_prot = pgprot_val(SEGMENT_KERNEL); 83 r3_prot = pgprot_val(REGION3_KERNEL); 84 if (!MACHINE_HAS_NX) { 85 pgt_prot &= ~_PAGE_NOEXEC; 86 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; 87 r3_prot &= ~_REGION_ENTRY_NOEXEC; 88 } 89 pages4k = pages1m = pages2g = 0; 90 while (address < end) { 91 pg_dir = pgd_offset_k(address); 92 if (pgd_none(*pg_dir)) { 93 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 94 if (!p4_dir) 95 goto out; 96 pgd_populate(&init_mm, pg_dir, p4_dir); 97 } 98 p4_dir = p4d_offset(pg_dir, address); 99 if (p4d_none(*p4_dir)) { 100 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 101 if (!pu_dir) 102 goto out; 103 p4d_populate(&init_mm, p4_dir, pu_dir); 104 } 105 pu_dir = pud_offset(p4_dir, address); 106 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address && 107 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) && 108 !debug_pagealloc_enabled()) { 109 pud_val(*pu_dir) = address | r3_prot; 110 address += PUD_SIZE; 111 pages2g++; 112 continue; 113 } 114 if (pud_none(*pu_dir)) { 115 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 116 if (!pm_dir) 117 goto out; 118 pud_populate(&init_mm, pu_dir, pm_dir); 119 } 120 pm_dir = pmd_offset(pu_dir, address); 121 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address && 122 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) && 123 !debug_pagealloc_enabled()) { 124 pmd_val(*pm_dir) = address | sgt_prot; 125 address += PMD_SIZE; 126 pages1m++; 127 continue; 128 } 129 if (pmd_none(*pm_dir)) { 130 pt_dir = vmem_pte_alloc(); 131 if (!pt_dir) 132 goto out; 133 pmd_populate(&init_mm, pm_dir, pt_dir); 134 } 135 136 pt_dir = pte_offset_kernel(pm_dir, address); 137 pte_val(*pt_dir) = address | pgt_prot; 138 address += PAGE_SIZE; 139 pages4k++; 140 } 141 ret = 0; 142 out: 143 update_page_count(PG_DIRECT_MAP_4K, pages4k); 144 update_page_count(PG_DIRECT_MAP_1M, pages1m); 145 update_page_count(PG_DIRECT_MAP_2G, pages2g); 146 return ret; 147 } 148 149 /* 150 * Remove a physical memory range from the 1:1 mapping. 151 * Currently only invalidates page table entries. 152 */ 153 static void vmem_remove_range(unsigned long start, unsigned long size) 154 { 155 unsigned long pages4k, pages1m, pages2g; 156 unsigned long end = start + size; 157 unsigned long address = start; 158 pgd_t *pg_dir; 159 p4d_t *p4_dir; 160 pud_t *pu_dir; 161 pmd_t *pm_dir; 162 pte_t *pt_dir; 163 164 pages4k = pages1m = pages2g = 0; 165 while (address < end) { 166 pg_dir = pgd_offset_k(address); 167 if (pgd_none(*pg_dir)) { 168 address += PGDIR_SIZE; 169 continue; 170 } 171 p4_dir = p4d_offset(pg_dir, address); 172 if (p4d_none(*p4_dir)) { 173 address += P4D_SIZE; 174 continue; 175 } 176 pu_dir = pud_offset(p4_dir, address); 177 if (pud_none(*pu_dir)) { 178 address += PUD_SIZE; 179 continue; 180 } 181 if (pud_large(*pu_dir)) { 182 pud_clear(pu_dir); 183 address += PUD_SIZE; 184 pages2g++; 185 continue; 186 } 187 pm_dir = pmd_offset(pu_dir, address); 188 if (pmd_none(*pm_dir)) { 189 address += PMD_SIZE; 190 continue; 191 } 192 if (pmd_large(*pm_dir)) { 193 pmd_clear(pm_dir); 194 address += PMD_SIZE; 195 pages1m++; 196 continue; 197 } 198 pt_dir = pte_offset_kernel(pm_dir, address); 199 pte_clear(&init_mm, address, pt_dir); 200 address += PAGE_SIZE; 201 pages4k++; 202 } 203 flush_tlb_kernel_range(start, end); 204 update_page_count(PG_DIRECT_MAP_4K, -pages4k); 205 update_page_count(PG_DIRECT_MAP_1M, -pages1m); 206 update_page_count(PG_DIRECT_MAP_2G, -pages2g); 207 } 208 209 /* 210 * Add a backed mem_map array to the virtual mem_map array. 211 */ 212 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 213 struct vmem_altmap *altmap) 214 { 215 unsigned long pgt_prot, sgt_prot; 216 unsigned long address = start; 217 pgd_t *pg_dir; 218 p4d_t *p4_dir; 219 pud_t *pu_dir; 220 pmd_t *pm_dir; 221 pte_t *pt_dir; 222 int ret = -ENOMEM; 223 224 pgt_prot = pgprot_val(PAGE_KERNEL); 225 sgt_prot = pgprot_val(SEGMENT_KERNEL); 226 if (!MACHINE_HAS_NX) { 227 pgt_prot &= ~_PAGE_NOEXEC; 228 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; 229 } 230 for (address = start; address < end;) { 231 pg_dir = pgd_offset_k(address); 232 if (pgd_none(*pg_dir)) { 233 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY); 234 if (!p4_dir) 235 goto out; 236 pgd_populate(&init_mm, pg_dir, p4_dir); 237 } 238 239 p4_dir = p4d_offset(pg_dir, address); 240 if (p4d_none(*p4_dir)) { 241 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY); 242 if (!pu_dir) 243 goto out; 244 p4d_populate(&init_mm, p4_dir, pu_dir); 245 } 246 247 pu_dir = pud_offset(p4_dir, address); 248 if (pud_none(*pu_dir)) { 249 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY); 250 if (!pm_dir) 251 goto out; 252 pud_populate(&init_mm, pu_dir, pm_dir); 253 } 254 255 pm_dir = pmd_offset(pu_dir, address); 256 if (pmd_none(*pm_dir)) { 257 /* Use 1MB frames for vmemmap if available. We always 258 * use large frames even if they are only partially 259 * used. 260 * Otherwise we would have also page tables since 261 * vmemmap_populate gets called for each section 262 * separately. */ 263 if (MACHINE_HAS_EDAT1) { 264 void *new_page; 265 266 new_page = vmemmap_alloc_block(PMD_SIZE, node); 267 if (!new_page) 268 goto out; 269 pmd_val(*pm_dir) = __pa(new_page) | sgt_prot; 270 address = (address + PMD_SIZE) & PMD_MASK; 271 continue; 272 } 273 pt_dir = vmem_pte_alloc(); 274 if (!pt_dir) 275 goto out; 276 pmd_populate(&init_mm, pm_dir, pt_dir); 277 } else if (pmd_large(*pm_dir)) { 278 address = (address + PMD_SIZE) & PMD_MASK; 279 continue; 280 } 281 282 pt_dir = pte_offset_kernel(pm_dir, address); 283 if (pte_none(*pt_dir)) { 284 void *new_page; 285 286 new_page = vmemmap_alloc_block(PAGE_SIZE, node); 287 if (!new_page) 288 goto out; 289 pte_val(*pt_dir) = __pa(new_page) | pgt_prot; 290 } 291 address += PAGE_SIZE; 292 } 293 ret = 0; 294 out: 295 return ret; 296 } 297 298 void vmemmap_free(unsigned long start, unsigned long end, 299 struct vmem_altmap *altmap) 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 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT, 416 SET_MEMORY_RO | SET_MEMORY_X); 417 418 /* we need lowcore executable for our LPSWE instructions */ 419 set_memory_x(0, 1); 420 421 pr_info("Write protected kernel read-only data: %luk\n", 422 (unsigned long)(__end_rodata - _stext) >> 10); 423 } 424 425 /* 426 * Convert memblock.memory to a memory segment list so there is a single 427 * list that contains all memory segments. 428 */ 429 static int __init vmem_convert_memory_chunk(void) 430 { 431 struct memblock_region *reg; 432 struct memory_segment *seg; 433 434 mutex_lock(&vmem_mutex); 435 for_each_memblock(memory, reg) { 436 seg = kzalloc(sizeof(*seg), GFP_KERNEL); 437 if (!seg) 438 panic("Out of memory...\n"); 439 seg->start = reg->base; 440 seg->size = reg->size; 441 insert_memory_segment(seg); 442 } 443 mutex_unlock(&vmem_mutex); 444 return 0; 445 } 446 447 core_initcall(vmem_convert_memory_chunk); 448