1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 7 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 8 * Copyright (C) 1996 Paul Mackerras 9 * 10 * Derived from "arch/i386/mm/init.c" 11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 12 * 13 * Dave Engebretsen <engebret@us.ibm.com> 14 * Rework for PPC64 port. 15 */ 16 17 #undef DEBUG 18 19 #include <linux/signal.h> 20 #include <linux/sched.h> 21 #include <linux/kernel.h> 22 #include <linux/errno.h> 23 #include <linux/string.h> 24 #include <linux/types.h> 25 #include <linux/mman.h> 26 #include <linux/mm.h> 27 #include <linux/swap.h> 28 #include <linux/stddef.h> 29 #include <linux/vmalloc.h> 30 #include <linux/init.h> 31 #include <linux/delay.h> 32 #include <linux/highmem.h> 33 #include <linux/idr.h> 34 #include <linux/nodemask.h> 35 #include <linux/module.h> 36 #include <linux/poison.h> 37 #include <linux/memblock.h> 38 #include <linux/hugetlb.h> 39 #include <linux/slab.h> 40 #include <linux/of_fdt.h> 41 #include <linux/libfdt.h> 42 #include <linux/memremap.h> 43 44 #include <asm/pgalloc.h> 45 #include <asm/page.h> 46 #include <asm/prom.h> 47 #include <asm/rtas.h> 48 #include <asm/io.h> 49 #include <asm/mmu_context.h> 50 #include <asm/mmu.h> 51 #include <linux/uaccess.h> 52 #include <asm/smp.h> 53 #include <asm/machdep.h> 54 #include <asm/tlb.h> 55 #include <asm/eeh.h> 56 #include <asm/processor.h> 57 #include <asm/mmzone.h> 58 #include <asm/cputable.h> 59 #include <asm/sections.h> 60 #include <asm/iommu.h> 61 #include <asm/vdso.h> 62 #include <asm/hugetlb.h> 63 64 #include <mm/mmu_decl.h> 65 66 #ifdef CONFIG_SPARSEMEM_VMEMMAP 67 /* 68 * Given an address within the vmemmap, determine the page that 69 * represents the start of the subsection it is within. Note that we have to 70 * do this by hand as the proffered address may not be correctly aligned. 71 * Subtraction of non-aligned pointers produces undefined results. 72 */ 73 static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_addr) 74 { 75 unsigned long start_pfn; 76 unsigned long offset = vmemmap_addr - ((unsigned long)(vmemmap)); 77 78 /* Return the pfn of the start of the section. */ 79 start_pfn = (offset / sizeof(struct page)) & PAGE_SUBSECTION_MASK; 80 return pfn_to_page(start_pfn); 81 } 82 83 /* 84 * Since memory is added in sub-section chunks, before creating a new vmemmap 85 * mapping, the kernel should check whether there is an existing memmap mapping 86 * covering the new subsection added. This is needed because kernel can map 87 * vmemmap area using 16MB pages which will cover a memory range of 16G. Such 88 * a range covers multiple subsections (2M) 89 * 90 * If any subsection in the 16G range mapped by vmemmap is valid we consider the 91 * vmemmap populated (There is a page table entry already present). We can't do 92 * a page table lookup here because with the hash translation we don't keep 93 * vmemmap details in linux page table. 94 */ 95 static int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size) 96 { 97 struct page *start; 98 unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size; 99 start = vmemmap_subsection_start(vmemmap_addr); 100 101 for (; (unsigned long)start < vmemmap_end; start += PAGES_PER_SUBSECTION) 102 /* 103 * pfn valid check here is intended to really check 104 * whether we have any subsection already initialized 105 * in this range. 106 */ 107 if (pfn_valid(page_to_pfn(start))) 108 return 1; 109 110 return 0; 111 } 112 113 /* 114 * vmemmap virtual address space management does not have a traditional page 115 * table to track which virtual struct pages are backed by physical mapping. 116 * The virtual to physical mappings are tracked in a simple linked list 117 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at 118 * all times where as the 'next' list maintains the available 119 * vmemmap_backing structures which have been deleted from the 120 * 'vmemmap_global' list during system runtime (memory hotplug remove 121 * operation). The freed 'vmemmap_backing' structures are reused later when 122 * new requests come in without allocating fresh memory. This pointer also 123 * tracks the allocated 'vmemmap_backing' structures as we allocate one 124 * full page memory at a time when we dont have any. 125 */ 126 struct vmemmap_backing *vmemmap_list; 127 static struct vmemmap_backing *next; 128 129 /* 130 * The same pointer 'next' tracks individual chunks inside the allocated 131 * full page during the boot time and again tracks the freed nodes during 132 * runtime. It is racy but it does not happen as they are separated by the 133 * boot process. Will create problem if some how we have memory hotplug 134 * operation during boot !! 135 */ 136 static int num_left; 137 static int num_freed; 138 139 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) 140 { 141 struct vmemmap_backing *vmem_back; 142 /* get from freed entries first */ 143 if (num_freed) { 144 num_freed--; 145 vmem_back = next; 146 next = next->list; 147 148 return vmem_back; 149 } 150 151 /* allocate a page when required and hand out chunks */ 152 if (!num_left) { 153 next = vmemmap_alloc_block(PAGE_SIZE, node); 154 if (unlikely(!next)) { 155 WARN_ON(1); 156 return NULL; 157 } 158 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); 159 } 160 161 num_left--; 162 163 return next++; 164 } 165 166 static __meminit int vmemmap_list_populate(unsigned long phys, 167 unsigned long start, 168 int node) 169 { 170 struct vmemmap_backing *vmem_back; 171 172 vmem_back = vmemmap_list_alloc(node); 173 if (unlikely(!vmem_back)) { 174 pr_debug("vmemap list allocation failed\n"); 175 return -ENOMEM; 176 } 177 178 vmem_back->phys = phys; 179 vmem_back->virt_addr = start; 180 vmem_back->list = vmemmap_list; 181 182 vmemmap_list = vmem_back; 183 return 0; 184 } 185 186 static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start, 187 unsigned long page_size) 188 { 189 unsigned long nr_pfn = page_size / sizeof(struct page); 190 unsigned long start_pfn = page_to_pfn((struct page *)start); 191 192 if ((start_pfn + nr_pfn - 1) > altmap->end_pfn) 193 return true; 194 195 if (start_pfn < altmap->base_pfn) 196 return true; 197 198 return false; 199 } 200 201 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 202 struct vmem_altmap *altmap) 203 { 204 bool altmap_alloc; 205 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 206 207 /* Align to the page size of the linear mapping. */ 208 start = ALIGN_DOWN(start, page_size); 209 210 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); 211 212 for (; start < end; start += page_size) { 213 void *p = NULL; 214 int rc; 215 216 /* 217 * This vmemmap range is backing different subsections. If any 218 * of that subsection is marked valid, that means we already 219 * have initialized a page table covering this range and hence 220 * the vmemmap range is populated. 221 */ 222 if (vmemmap_populated(start, page_size)) 223 continue; 224 225 /* 226 * Allocate from the altmap first if we have one. This may 227 * fail due to alignment issues when using 16MB hugepages, so 228 * fall back to system memory if the altmap allocation fail. 229 */ 230 if (altmap && !altmap_cross_boundary(altmap, start, page_size)) { 231 p = vmemmap_alloc_block_buf(page_size, node, altmap); 232 if (!p) 233 pr_debug("altmap block allocation failed, falling back to system memory"); 234 else 235 altmap_alloc = true; 236 } 237 if (!p) { 238 p = vmemmap_alloc_block_buf(page_size, node, NULL); 239 altmap_alloc = false; 240 } 241 if (!p) 242 return -ENOMEM; 243 244 if (vmemmap_list_populate(__pa(p), start, node)) { 245 /* 246 * If we don't populate vmemap list, we don't have 247 * the ability to free the allocated vmemmap 248 * pages in section_deactivate. Hence free them 249 * here. 250 */ 251 int nr_pfns = page_size >> PAGE_SHIFT; 252 unsigned long page_order = get_order(page_size); 253 254 if (altmap_alloc) 255 vmem_altmap_free(altmap, nr_pfns); 256 else 257 free_pages((unsigned long)p, page_order); 258 return -ENOMEM; 259 } 260 261 pr_debug(" * %016lx..%016lx allocated at %p\n", 262 start, start + page_size, p); 263 264 rc = vmemmap_create_mapping(start, page_size, __pa(p)); 265 if (rc < 0) { 266 pr_warn("%s: Unable to create vmemmap mapping: %d\n", 267 __func__, rc); 268 return -EFAULT; 269 } 270 } 271 272 return 0; 273 } 274 275 #ifdef CONFIG_MEMORY_HOTPLUG 276 static unsigned long vmemmap_list_free(unsigned long start) 277 { 278 struct vmemmap_backing *vmem_back, *vmem_back_prev; 279 280 vmem_back_prev = vmem_back = vmemmap_list; 281 282 /* look for it with prev pointer recorded */ 283 for (; vmem_back; vmem_back = vmem_back->list) { 284 if (vmem_back->virt_addr == start) 285 break; 286 vmem_back_prev = vmem_back; 287 } 288 289 if (unlikely(!vmem_back)) 290 return 0; 291 292 /* remove it from vmemmap_list */ 293 if (vmem_back == vmemmap_list) /* remove head */ 294 vmemmap_list = vmem_back->list; 295 else 296 vmem_back_prev->list = vmem_back->list; 297 298 /* next point to this freed entry */ 299 vmem_back->list = next; 300 next = vmem_back; 301 num_freed++; 302 303 return vmem_back->phys; 304 } 305 306 void __ref vmemmap_free(unsigned long start, unsigned long end, 307 struct vmem_altmap *altmap) 308 { 309 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 310 unsigned long page_order = get_order(page_size); 311 unsigned long alt_start = ~0, alt_end = ~0; 312 unsigned long base_pfn; 313 314 start = ALIGN_DOWN(start, page_size); 315 if (altmap) { 316 alt_start = altmap->base_pfn; 317 alt_end = altmap->base_pfn + altmap->reserve + altmap->free; 318 } 319 320 pr_debug("vmemmap_free %lx...%lx\n", start, end); 321 322 for (; start < end; start += page_size) { 323 unsigned long nr_pages, addr; 324 struct page *page; 325 326 /* 327 * We have already marked the subsection we are trying to remove 328 * invalid. So if we want to remove the vmemmap range, we 329 * need to make sure there is no subsection marked valid 330 * in this range. 331 */ 332 if (vmemmap_populated(start, page_size)) 333 continue; 334 335 addr = vmemmap_list_free(start); 336 if (!addr) 337 continue; 338 339 page = pfn_to_page(addr >> PAGE_SHIFT); 340 nr_pages = 1 << page_order; 341 base_pfn = PHYS_PFN(addr); 342 343 if (base_pfn >= alt_start && base_pfn < alt_end) { 344 vmem_altmap_free(altmap, nr_pages); 345 } else if (PageReserved(page)) { 346 /* allocated from bootmem */ 347 if (page_size < PAGE_SIZE) { 348 /* 349 * this shouldn't happen, but if it is 350 * the case, leave the memory there 351 */ 352 WARN_ON_ONCE(1); 353 } else { 354 while (nr_pages--) 355 free_reserved_page(page++); 356 } 357 } else { 358 free_pages((unsigned long)(__va(addr)), page_order); 359 } 360 361 vmemmap_remove_mapping(start, page_size); 362 } 363 } 364 #endif 365 void register_page_bootmem_memmap(unsigned long section_nr, 366 struct page *start_page, unsigned long size) 367 { 368 } 369 370 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 371 372 #ifdef CONFIG_PPC_BOOK3S_64 373 unsigned int mmu_lpid_bits; 374 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE 375 EXPORT_SYMBOL_GPL(mmu_lpid_bits); 376 #endif 377 unsigned int mmu_pid_bits; 378 379 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT); 380 381 static int __init parse_disable_radix(char *p) 382 { 383 bool val; 384 385 if (!p) 386 val = true; 387 else if (kstrtobool(p, &val)) 388 return -EINVAL; 389 390 disable_radix = val; 391 392 return 0; 393 } 394 early_param("disable_radix", parse_disable_radix); 395 396 /* 397 * If we're running under a hypervisor, we need to check the contents of 398 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do 399 * radix. If not, we clear the radix feature bit so we fall back to hash. 400 */ 401 static void __init early_check_vec5(void) 402 { 403 unsigned long root, chosen; 404 int size; 405 const u8 *vec5; 406 u8 mmu_supported; 407 408 root = of_get_flat_dt_root(); 409 chosen = of_get_flat_dt_subnode_by_name(root, "chosen"); 410 if (chosen == -FDT_ERR_NOTFOUND) { 411 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 412 return; 413 } 414 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size); 415 if (!vec5) { 416 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 417 return; 418 } 419 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) { 420 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 421 return; 422 } 423 424 /* Check for supported configuration */ 425 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] & 426 OV5_FEAT(OV5_MMU_SUPPORT); 427 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) { 428 /* Hypervisor only supports radix - check enabled && GTSE */ 429 if (!early_radix_enabled()) { 430 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 431 } 432 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] & 433 OV5_FEAT(OV5_RADIX_GTSE))) { 434 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE; 435 } else 436 cur_cpu_spec->mmu_features |= MMU_FTR_GTSE; 437 /* Do radix anyway - the hypervisor said we had to */ 438 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX; 439 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) { 440 /* Hypervisor only supports hash - disable radix */ 441 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 442 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE; 443 } 444 } 445 446 static int __init dt_scan_mmu_pid_width(unsigned long node, 447 const char *uname, int depth, 448 void *data) 449 { 450 int size = 0; 451 const __be32 *prop; 452 const char *type = of_get_flat_dt_prop(node, "device_type", NULL); 453 454 /* We are scanning "cpu" nodes only */ 455 if (type == NULL || strcmp(type, "cpu") != 0) 456 return 0; 457 458 /* Find MMU LPID, PID register size */ 459 prop = of_get_flat_dt_prop(node, "ibm,mmu-lpid-bits", &size); 460 if (prop && size == 4) 461 mmu_lpid_bits = be32_to_cpup(prop); 462 463 prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size); 464 if (prop && size == 4) 465 mmu_pid_bits = be32_to_cpup(prop); 466 467 if (!mmu_pid_bits && !mmu_lpid_bits) 468 return 0; 469 470 return 1; 471 } 472 473 void __init mmu_early_init_devtree(void) 474 { 475 bool hvmode = !!(mfmsr() & MSR_HV); 476 477 /* Disable radix mode based on kernel command line. */ 478 if (disable_radix) { 479 if (IS_ENABLED(CONFIG_PPC_64S_HASH_MMU)) 480 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 481 else 482 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 483 } 484 485 of_scan_flat_dt(dt_scan_mmu_pid_width, NULL); 486 if (hvmode && !mmu_lpid_bits) { 487 if (early_cpu_has_feature(CPU_FTR_ARCH_207S)) 488 mmu_lpid_bits = 12; /* POWER8-10 */ 489 else 490 mmu_lpid_bits = 10; /* POWER7 */ 491 } 492 if (!mmu_pid_bits) { 493 if (early_cpu_has_feature(CPU_FTR_ARCH_300)) 494 mmu_pid_bits = 20; /* POWER9-10 */ 495 } 496 497 /* 498 * Check /chosen/ibm,architecture-vec-5 if running as a guest. 499 * When running bare-metal, we can use radix if we like 500 * even though the ibm,architecture-vec-5 property created by 501 * skiboot doesn't have the necessary bits set. 502 */ 503 if (!hvmode) 504 early_check_vec5(); 505 506 if (early_radix_enabled()) { 507 radix__early_init_devtree(); 508 509 /* 510 * We have finalized the translation we are going to use by now. 511 * Radix mode is not limited by RMA / VRMA addressing. 512 * Hence don't limit memblock allocations. 513 */ 514 ppc64_rma_size = ULONG_MAX; 515 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE); 516 } else 517 hash__early_init_devtree(); 518 519 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE)) 520 hugetlbpage_init_defaultsize(); 521 522 if (!(cur_cpu_spec->mmu_features & MMU_FTR_HPTE_TABLE) && 523 !(cur_cpu_spec->mmu_features & MMU_FTR_TYPE_RADIX)) 524 panic("kernel does not support any MMU type offered by platform"); 525 } 526 #endif /* CONFIG_PPC_BOOK3S_64 */ 527