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 #include <linux/memory.h> 44 #include <linux/bootmem_info.h> 45 46 #include <asm/pgalloc.h> 47 #include <asm/page.h> 48 #include <asm/prom.h> 49 #include <asm/rtas.h> 50 #include <asm/io.h> 51 #include <asm/mmu_context.h> 52 #include <asm/mmu.h> 53 #include <linux/uaccess.h> 54 #include <asm/smp.h> 55 #include <asm/machdep.h> 56 #include <asm/tlb.h> 57 #include <asm/eeh.h> 58 #include <asm/processor.h> 59 #include <asm/mmzone.h> 60 #include <asm/cputable.h> 61 #include <asm/sections.h> 62 #include <asm/iommu.h> 63 #include <asm/vdso.h> 64 #include <asm/hugetlb.h> 65 66 #include <mm/mmu_decl.h> 67 68 #ifdef CONFIG_SPARSEMEM_VMEMMAP 69 /* 70 * Given an address within the vmemmap, determine the page that 71 * represents the start of the subsection it is within. Note that we have to 72 * do this by hand as the proffered address may not be correctly aligned. 73 * Subtraction of non-aligned pointers produces undefined results. 74 */ 75 static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_addr) 76 { 77 unsigned long start_pfn; 78 unsigned long offset = vmemmap_addr - ((unsigned long)(vmemmap)); 79 80 /* Return the pfn of the start of the section. */ 81 start_pfn = (offset / sizeof(struct page)) & PAGE_SUBSECTION_MASK; 82 return pfn_to_page(start_pfn); 83 } 84 85 /* 86 * Since memory is added in sub-section chunks, before creating a new vmemmap 87 * mapping, the kernel should check whether there is an existing memmap mapping 88 * covering the new subsection added. This is needed because kernel can map 89 * vmemmap area using 16MB pages which will cover a memory range of 16G. Such 90 * a range covers multiple subsections (2M) 91 * 92 * If any subsection in the 16G range mapped by vmemmap is valid we consider the 93 * vmemmap populated (There is a page table entry already present). We can't do 94 * a page table lookup here because with the hash translation we don't keep 95 * vmemmap details in linux page table. 96 */ 97 int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size) 98 { 99 struct page *start; 100 unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size; 101 start = vmemmap_subsection_start(vmemmap_addr); 102 103 for (; (unsigned long)start < vmemmap_end; start += PAGES_PER_SUBSECTION) 104 /* 105 * pfn valid check here is intended to really check 106 * whether we have any subsection already initialized 107 * in this range. 108 */ 109 if (pfn_valid(page_to_pfn(start))) 110 return 1; 111 112 return 0; 113 } 114 115 /* 116 * vmemmap virtual address space management does not have a traditional page 117 * table to track which virtual struct pages are backed by physical mapping. 118 * The virtual to physical mappings are tracked in a simple linked list 119 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at 120 * all times where as the 'next' list maintains the available 121 * vmemmap_backing structures which have been deleted from the 122 * 'vmemmap_global' list during system runtime (memory hotplug remove 123 * operation). The freed 'vmemmap_backing' structures are reused later when 124 * new requests come in without allocating fresh memory. This pointer also 125 * tracks the allocated 'vmemmap_backing' structures as we allocate one 126 * full page memory at a time when we dont have any. 127 */ 128 struct vmemmap_backing *vmemmap_list; 129 static struct vmemmap_backing *next; 130 131 /* 132 * The same pointer 'next' tracks individual chunks inside the allocated 133 * full page during the boot time and again tracks the freed nodes during 134 * runtime. It is racy but it does not happen as they are separated by the 135 * boot process. Will create problem if some how we have memory hotplug 136 * operation during boot !! 137 */ 138 static int num_left; 139 static int num_freed; 140 141 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) 142 { 143 struct vmemmap_backing *vmem_back; 144 /* get from freed entries first */ 145 if (num_freed) { 146 num_freed--; 147 vmem_back = next; 148 next = next->list; 149 150 return vmem_back; 151 } 152 153 /* allocate a page when required and hand out chunks */ 154 if (!num_left) { 155 next = vmemmap_alloc_block(PAGE_SIZE, node); 156 if (unlikely(!next)) { 157 WARN_ON(1); 158 return NULL; 159 } 160 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); 161 } 162 163 num_left--; 164 165 return next++; 166 } 167 168 static __meminit int vmemmap_list_populate(unsigned long phys, 169 unsigned long start, 170 int node) 171 { 172 struct vmemmap_backing *vmem_back; 173 174 vmem_back = vmemmap_list_alloc(node); 175 if (unlikely(!vmem_back)) { 176 pr_debug("vmemap list allocation failed\n"); 177 return -ENOMEM; 178 } 179 180 vmem_back->phys = phys; 181 vmem_back->virt_addr = start; 182 vmem_back->list = vmemmap_list; 183 184 vmemmap_list = vmem_back; 185 return 0; 186 } 187 188 bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start, 189 unsigned long page_size) 190 { 191 unsigned long nr_pfn = page_size / sizeof(struct page); 192 unsigned long start_pfn = page_to_pfn((struct page *)start); 193 194 if ((start_pfn + nr_pfn - 1) > altmap->end_pfn) 195 return true; 196 197 if (start_pfn < altmap->base_pfn) 198 return true; 199 200 return false; 201 } 202 203 static int __meminit __vmemmap_populate(unsigned long start, unsigned long end, int node, 204 struct vmem_altmap *altmap) 205 { 206 bool altmap_alloc; 207 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 208 209 /* Align to the page size of the linear mapping. */ 210 start = ALIGN_DOWN(start, page_size); 211 212 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); 213 214 for (; start < end; start += page_size) { 215 void *p = NULL; 216 int rc; 217 218 /* 219 * This vmemmap range is backing different subsections. If any 220 * of that subsection is marked valid, that means we already 221 * have initialized a page table covering this range and hence 222 * the vmemmap range is populated. 223 */ 224 if (vmemmap_populated(start, page_size)) 225 continue; 226 227 /* 228 * Allocate from the altmap first if we have one. This may 229 * fail due to alignment issues when using 16MB hugepages, so 230 * fall back to system memory if the altmap allocation fail. 231 */ 232 if (altmap && !altmap_cross_boundary(altmap, start, page_size)) { 233 p = vmemmap_alloc_block_buf(page_size, node, altmap); 234 if (!p) 235 pr_debug("altmap block allocation failed, falling back to system memory"); 236 else 237 altmap_alloc = true; 238 } 239 if (!p) { 240 p = vmemmap_alloc_block_buf(page_size, node, NULL); 241 altmap_alloc = false; 242 } 243 if (!p) 244 return -ENOMEM; 245 246 if (vmemmap_list_populate(__pa(p), start, node)) { 247 /* 248 * If we don't populate vmemap list, we don't have 249 * the ability to free the allocated vmemmap 250 * pages in section_deactivate. Hence free them 251 * here. 252 */ 253 int nr_pfns = page_size >> PAGE_SHIFT; 254 unsigned long page_order = get_order(page_size); 255 256 if (altmap_alloc) 257 vmem_altmap_free(altmap, nr_pfns); 258 else 259 free_pages((unsigned long)p, page_order); 260 return -ENOMEM; 261 } 262 263 pr_debug(" * %016lx..%016lx allocated at %p\n", 264 start, start + page_size, p); 265 266 rc = vmemmap_create_mapping(start, page_size, __pa(p)); 267 if (rc < 0) { 268 pr_warn("%s: Unable to create vmemmap mapping: %d\n", 269 __func__, rc); 270 return -EFAULT; 271 } 272 } 273 274 return 0; 275 } 276 277 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 278 struct vmem_altmap *altmap) 279 { 280 281 #ifdef CONFIG_PPC_BOOK3S_64 282 if (radix_enabled()) 283 return radix__vmemmap_populate(start, end, node, altmap); 284 #endif 285 286 return __vmemmap_populate(start, end, node, altmap); 287 } 288 289 #ifdef CONFIG_MEMORY_HOTPLUG 290 static unsigned long vmemmap_list_free(unsigned long start) 291 { 292 struct vmemmap_backing *vmem_back, *vmem_back_prev; 293 294 vmem_back_prev = vmem_back = vmemmap_list; 295 296 /* look for it with prev pointer recorded */ 297 for (; vmem_back; vmem_back = vmem_back->list) { 298 if (vmem_back->virt_addr == start) 299 break; 300 vmem_back_prev = vmem_back; 301 } 302 303 if (unlikely(!vmem_back)) 304 return 0; 305 306 /* remove it from vmemmap_list */ 307 if (vmem_back == vmemmap_list) /* remove head */ 308 vmemmap_list = vmem_back->list; 309 else 310 vmem_back_prev->list = vmem_back->list; 311 312 /* next point to this freed entry */ 313 vmem_back->list = next; 314 next = vmem_back; 315 num_freed++; 316 317 return vmem_back->phys; 318 } 319 320 static void __ref __vmemmap_free(unsigned long start, unsigned long end, 321 struct vmem_altmap *altmap) 322 { 323 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 324 unsigned long page_order = get_order(page_size); 325 unsigned long alt_start = ~0, alt_end = ~0; 326 unsigned long base_pfn; 327 328 start = ALIGN_DOWN(start, page_size); 329 if (altmap) { 330 alt_start = altmap->base_pfn; 331 alt_end = altmap->base_pfn + altmap->reserve + altmap->free; 332 } 333 334 pr_debug("vmemmap_free %lx...%lx\n", start, end); 335 336 for (; start < end; start += page_size) { 337 unsigned long nr_pages, addr; 338 struct page *page; 339 340 /* 341 * We have already marked the subsection we are trying to remove 342 * invalid. So if we want to remove the vmemmap range, we 343 * need to make sure there is no subsection marked valid 344 * in this range. 345 */ 346 if (vmemmap_populated(start, page_size)) 347 continue; 348 349 addr = vmemmap_list_free(start); 350 if (!addr) 351 continue; 352 353 page = pfn_to_page(addr >> PAGE_SHIFT); 354 nr_pages = 1 << page_order; 355 base_pfn = PHYS_PFN(addr); 356 357 if (base_pfn >= alt_start && base_pfn < alt_end) { 358 vmem_altmap_free(altmap, nr_pages); 359 } else if (PageReserved(page)) { 360 /* allocated from bootmem */ 361 if (page_size < PAGE_SIZE) { 362 /* 363 * this shouldn't happen, but if it is 364 * the case, leave the memory there 365 */ 366 WARN_ON_ONCE(1); 367 } else { 368 while (nr_pages--) 369 free_reserved_page(page++); 370 } 371 } else { 372 free_pages((unsigned long)(__va(addr)), page_order); 373 } 374 375 vmemmap_remove_mapping(start, page_size); 376 } 377 } 378 379 void __ref vmemmap_free(unsigned long start, unsigned long end, 380 struct vmem_altmap *altmap) 381 { 382 #ifdef CONFIG_PPC_BOOK3S_64 383 if (radix_enabled()) 384 return radix__vmemmap_free(start, end, altmap); 385 #endif 386 return __vmemmap_free(start, end, altmap); 387 } 388 389 #endif 390 391 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE 392 void register_page_bootmem_memmap(unsigned long section_nr, 393 struct page *start_page, unsigned long size) 394 { 395 } 396 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */ 397 398 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 399 400 #ifdef CONFIG_PPC_BOOK3S_64 401 unsigned int mmu_lpid_bits; 402 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE 403 EXPORT_SYMBOL_GPL(mmu_lpid_bits); 404 #endif 405 unsigned int mmu_pid_bits; 406 407 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT); 408 409 static int __init parse_disable_radix(char *p) 410 { 411 bool val; 412 413 if (!p) 414 val = true; 415 else if (kstrtobool(p, &val)) 416 return -EINVAL; 417 418 disable_radix = val; 419 420 return 0; 421 } 422 early_param("disable_radix", parse_disable_radix); 423 424 /* 425 * If we're running under a hypervisor, we need to check the contents of 426 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do 427 * radix. If not, we clear the radix feature bit so we fall back to hash. 428 */ 429 static void __init early_check_vec5(void) 430 { 431 unsigned long root, chosen; 432 int size; 433 const u8 *vec5; 434 u8 mmu_supported; 435 436 root = of_get_flat_dt_root(); 437 chosen = of_get_flat_dt_subnode_by_name(root, "chosen"); 438 if (chosen == -FDT_ERR_NOTFOUND) { 439 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 440 return; 441 } 442 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size); 443 if (!vec5) { 444 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 445 return; 446 } 447 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) { 448 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 449 return; 450 } 451 452 /* Check for supported configuration */ 453 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] & 454 OV5_FEAT(OV5_MMU_SUPPORT); 455 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) { 456 /* Hypervisor only supports radix - check enabled && GTSE */ 457 if (!early_radix_enabled()) { 458 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 459 } 460 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] & 461 OV5_FEAT(OV5_RADIX_GTSE))) { 462 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE; 463 } else 464 cur_cpu_spec->mmu_features |= MMU_FTR_GTSE; 465 /* Do radix anyway - the hypervisor said we had to */ 466 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX; 467 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) { 468 /* Hypervisor only supports hash - disable radix */ 469 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 470 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE; 471 } 472 } 473 474 static int __init dt_scan_mmu_pid_width(unsigned long node, 475 const char *uname, int depth, 476 void *data) 477 { 478 int size = 0; 479 const __be32 *prop; 480 const char *type = of_get_flat_dt_prop(node, "device_type", NULL); 481 482 /* We are scanning "cpu" nodes only */ 483 if (type == NULL || strcmp(type, "cpu") != 0) 484 return 0; 485 486 /* Find MMU LPID, PID register size */ 487 prop = of_get_flat_dt_prop(node, "ibm,mmu-lpid-bits", &size); 488 if (prop && size == 4) 489 mmu_lpid_bits = be32_to_cpup(prop); 490 491 prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size); 492 if (prop && size == 4) 493 mmu_pid_bits = be32_to_cpup(prop); 494 495 if (!mmu_pid_bits && !mmu_lpid_bits) 496 return 0; 497 498 return 1; 499 } 500 501 /* 502 * Outside hotplug the kernel uses this value to map the kernel direct map 503 * with radix. To be compatible with older kernels, let's keep this value 504 * as 16M which is also SECTION_SIZE with SPARSEMEM. We can ideally map 505 * things with 1GB size in the case where we don't support hotplug. 506 */ 507 #ifndef CONFIG_MEMORY_HOTPLUG 508 #define DEFAULT_MEMORY_BLOCK_SIZE SZ_16M 509 #else 510 #define DEFAULT_MEMORY_BLOCK_SIZE MIN_MEMORY_BLOCK_SIZE 511 #endif 512 513 static void update_memory_block_size(unsigned long *block_size, unsigned long mem_size) 514 { 515 unsigned long min_memory_block_size = DEFAULT_MEMORY_BLOCK_SIZE; 516 517 for (; *block_size > min_memory_block_size; *block_size >>= 2) { 518 if ((mem_size & *block_size) == 0) 519 break; 520 } 521 } 522 523 static int __init probe_memory_block_size(unsigned long node, const char *uname, int 524 depth, void *data) 525 { 526 const char *type; 527 unsigned long *block_size = (unsigned long *)data; 528 const __be32 *reg, *endp; 529 int l; 530 531 if (depth != 1) 532 return 0; 533 /* 534 * If we have dynamic-reconfiguration-memory node, use the 535 * lmb value. 536 */ 537 if (strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0) { 538 539 const __be32 *prop; 540 541 prop = of_get_flat_dt_prop(node, "ibm,lmb-size", &l); 542 543 if (!prop || l < dt_root_size_cells * sizeof(__be32)) 544 /* 545 * Nothing in the device tree 546 */ 547 *block_size = DEFAULT_MEMORY_BLOCK_SIZE; 548 else 549 *block_size = of_read_number(prop, dt_root_size_cells); 550 /* 551 * We have found the final value. Don't probe further. 552 */ 553 return 1; 554 } 555 /* 556 * Find all the device tree nodes of memory type and make sure 557 * the area can be mapped using the memory block size value 558 * we end up using. We start with 1G value and keep reducing 559 * it such that we can map the entire area using memory_block_size. 560 * This will be used on powernv and older pseries that don't 561 * have ibm,lmb-size node. 562 * For ex: with P5 we can end up with 563 * memory@0 -> 128MB 564 * memory@128M -> 64M 565 * This will end up using 64MB memory block size value. 566 */ 567 type = of_get_flat_dt_prop(node, "device_type", NULL); 568 if (type == NULL || strcmp(type, "memory") != 0) 569 return 0; 570 571 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l); 572 if (!reg) 573 reg = of_get_flat_dt_prop(node, "reg", &l); 574 if (!reg) 575 return 0; 576 577 endp = reg + (l / sizeof(__be32)); 578 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { 579 const char *compatible; 580 u64 size; 581 582 dt_mem_next_cell(dt_root_addr_cells, ®); 583 size = dt_mem_next_cell(dt_root_size_cells, ®); 584 585 if (size) { 586 update_memory_block_size(block_size, size); 587 continue; 588 } 589 /* 590 * ibm,coherent-device-memory with linux,usable-memory = 0 591 * Force 256MiB block size. Work around for GPUs on P9 PowerNV 592 * linux,usable-memory == 0 implies driver managed memory and 593 * we can't use large memory block size due to hotplug/unplug 594 * limitations. 595 */ 596 compatible = of_get_flat_dt_prop(node, "compatible", NULL); 597 if (compatible && !strcmp(compatible, "ibm,coherent-device-memory")) { 598 if (*block_size > SZ_256M) 599 *block_size = SZ_256M; 600 /* 601 * We keep 256M as the upper limit with GPU present. 602 */ 603 return 0; 604 } 605 } 606 /* continue looking for other memory device types */ 607 return 0; 608 } 609 610 /* 611 * start with 1G memory block size. Early init will 612 * fix this with correct value. 613 */ 614 unsigned long memory_block_size __ro_after_init = 1UL << 30; 615 static void __init early_init_memory_block_size(void) 616 { 617 /* 618 * We need to do memory_block_size probe early so that 619 * radix__early_init_mmu() can use this as limit for 620 * mapping page size. 621 */ 622 of_scan_flat_dt(probe_memory_block_size, &memory_block_size); 623 } 624 625 void __init mmu_early_init_devtree(void) 626 { 627 bool hvmode = !!(mfmsr() & MSR_HV); 628 629 /* Disable radix mode based on kernel command line. */ 630 if (disable_radix) { 631 if (IS_ENABLED(CONFIG_PPC_64S_HASH_MMU)) 632 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 633 else 634 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 635 } 636 637 of_scan_flat_dt(dt_scan_mmu_pid_width, NULL); 638 if (hvmode && !mmu_lpid_bits) { 639 if (early_cpu_has_feature(CPU_FTR_ARCH_207S)) 640 mmu_lpid_bits = 12; /* POWER8-10 */ 641 else 642 mmu_lpid_bits = 10; /* POWER7 */ 643 } 644 if (!mmu_pid_bits) { 645 if (early_cpu_has_feature(CPU_FTR_ARCH_300)) 646 mmu_pid_bits = 20; /* POWER9-10 */ 647 } 648 649 /* 650 * Check /chosen/ibm,architecture-vec-5 if running as a guest. 651 * When running bare-metal, we can use radix if we like 652 * even though the ibm,architecture-vec-5 property created by 653 * skiboot doesn't have the necessary bits set. 654 */ 655 if (!hvmode) 656 early_check_vec5(); 657 658 early_init_memory_block_size(); 659 660 if (early_radix_enabled()) { 661 radix__early_init_devtree(); 662 663 /* 664 * We have finalized the translation we are going to use by now. 665 * Radix mode is not limited by RMA / VRMA addressing. 666 * Hence don't limit memblock allocations. 667 */ 668 ppc64_rma_size = ULONG_MAX; 669 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE); 670 } else 671 hash__early_init_devtree(); 672 673 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE)) 674 hugetlbpage_init_defaultsize(); 675 676 if (!(cur_cpu_spec->mmu_features & MMU_FTR_HPTE_TABLE) && 677 !(cur_cpu_spec->mmu_features & MMU_FTR_TYPE_RADIX)) 678 panic("kernel does not support any MMU type offered by platform"); 679 } 680 #endif /* CONFIG_PPC_BOOK3S_64 */ 681