1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/mm/init.c 4 * 5 * Copyright (C) 1995-2005 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/export.h> 11 #include <linux/errno.h> 12 #include <linux/swap.h> 13 #include <linux/init.h> 14 #include <linux/cache.h> 15 #include <linux/mman.h> 16 #include <linux/nodemask.h> 17 #include <linux/initrd.h> 18 #include <linux/gfp.h> 19 #include <linux/math.h> 20 #include <linux/memblock.h> 21 #include <linux/sort.h> 22 #include <linux/of.h> 23 #include <linux/of_fdt.h> 24 #include <linux/dma-direct.h> 25 #include <linux/dma-map-ops.h> 26 #include <linux/efi.h> 27 #include <linux/swiotlb.h> 28 #include <linux/vmalloc.h> 29 #include <linux/mm.h> 30 #include <linux/kexec.h> 31 #include <linux/crash_dump.h> 32 #include <linux/hugetlb.h> 33 #include <linux/acpi_iort.h> 34 #include <linux/kmemleak.h> 35 #include <linux/execmem.h> 36 37 #include <asm/boot.h> 38 #include <asm/fixmap.h> 39 #include <asm/kasan.h> 40 #include <asm/kernel-pgtable.h> 41 #include <asm/kvm_host.h> 42 #include <asm/memory.h> 43 #include <asm/numa.h> 44 #include <asm/rsi.h> 45 #include <asm/sections.h> 46 #include <asm/setup.h> 47 #include <linux/sizes.h> 48 #include <asm/tlb.h> 49 #include <asm/alternative.h> 50 #include <asm/xen/swiotlb-xen.h> 51 52 /* 53 * We need to be able to catch inadvertent references to memstart_addr 54 * that occur (potentially in generic code) before arm64_memblock_init() 55 * executes, which assigns it its actual value. So use a default value 56 * that cannot be mistaken for a real physical address. 57 */ 58 s64 memstart_addr __ro_after_init = -1; 59 EXPORT_SYMBOL(memstart_addr); 60 61 /* 62 * If the corresponding config options are enabled, we create both ZONE_DMA 63 * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory 64 * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4). 65 * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory, 66 * otherwise it is empty. 67 */ 68 phys_addr_t __ro_after_init arm64_dma_phys_limit; 69 70 /* 71 * To make optimal use of block mappings when laying out the linear 72 * mapping, round down the base of physical memory to a size that can 73 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE 74 * (64k granule), or a multiple that can be mapped using contiguous bits 75 * in the page tables: 32 * PMD_SIZE (16k granule) 76 */ 77 #if defined(CONFIG_ARM64_4K_PAGES) 78 #define ARM64_MEMSTART_SHIFT PUD_SHIFT 79 #elif defined(CONFIG_ARM64_16K_PAGES) 80 #define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT 81 #else 82 #define ARM64_MEMSTART_SHIFT PMD_SHIFT 83 #endif 84 85 /* 86 * sparsemem vmemmap imposes an additional requirement on the alignment of 87 * memstart_addr, due to the fact that the base of the vmemmap region 88 * has a direct correspondence, and needs to appear sufficiently aligned 89 * in the virtual address space. 90 */ 91 #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS 92 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) 93 #else 94 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) 95 #endif 96 97 static void __init arch_reserve_crashkernel(void) 98 { 99 unsigned long long low_size = 0; 100 unsigned long long crash_base, crash_size; 101 char *cmdline = boot_command_line; 102 bool high = false; 103 int ret; 104 105 if (!IS_ENABLED(CONFIG_CRASH_RESERVE)) 106 return; 107 108 ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), 109 &crash_size, &crash_base, 110 &low_size, &high); 111 if (ret) 112 return; 113 114 reserve_crashkernel_generic(cmdline, crash_size, crash_base, 115 low_size, high); 116 } 117 118 static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit) 119 { 120 /** 121 * Information we get from firmware (e.g. DT dma-ranges) describe DMA 122 * bus constraints. Devices using DMA might have their own limitations. 123 * Some of them rely on DMA zone in low 32-bit memory. Keep low RAM 124 * DMA zone on platforms that have RAM there. 125 */ 126 if (memblock_start_of_DRAM() < U32_MAX) 127 zone_limit = min(zone_limit, U32_MAX); 128 129 return min(zone_limit, memblock_end_of_DRAM() - 1) + 1; 130 } 131 132 static void __init zone_sizes_init(void) 133 { 134 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; 135 phys_addr_t __maybe_unused acpi_zone_dma_limit; 136 phys_addr_t __maybe_unused dt_zone_dma_limit; 137 phys_addr_t __maybe_unused dma32_phys_limit = 138 max_zone_phys(DMA_BIT_MASK(32)); 139 140 #ifdef CONFIG_ZONE_DMA 141 acpi_zone_dma_limit = acpi_iort_dma_get_max_cpu_address(); 142 dt_zone_dma_limit = of_dma_get_max_cpu_address(NULL); 143 zone_dma_limit = min(dt_zone_dma_limit, acpi_zone_dma_limit); 144 arm64_dma_phys_limit = max_zone_phys(zone_dma_limit); 145 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit); 146 #endif 147 #ifdef CONFIG_ZONE_DMA32 148 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); 149 if (!arm64_dma_phys_limit) 150 arm64_dma_phys_limit = dma32_phys_limit; 151 #endif 152 if (!arm64_dma_phys_limit) 153 arm64_dma_phys_limit = PHYS_MASK + 1; 154 max_zone_pfns[ZONE_NORMAL] = max_pfn; 155 156 free_area_init(max_zone_pfns); 157 } 158 159 int pfn_is_map_memory(unsigned long pfn) 160 { 161 phys_addr_t addr = PFN_PHYS(pfn); 162 163 /* avoid false positives for bogus PFNs, see comment in pfn_valid() */ 164 if (PHYS_PFN(addr) != pfn) 165 return 0; 166 167 return memblock_is_map_memory(addr); 168 } 169 EXPORT_SYMBOL(pfn_is_map_memory); 170 171 static phys_addr_t memory_limit __ro_after_init = PHYS_ADDR_MAX; 172 173 /* 174 * Limit the memory size that was specified via FDT. 175 */ 176 static int __init early_mem(char *p) 177 { 178 if (!p) 179 return 1; 180 181 memory_limit = memparse(p, &p) & PAGE_MASK; 182 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); 183 184 return 0; 185 } 186 early_param("mem", early_mem); 187 188 void __init arm64_memblock_init(void) 189 { 190 s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); 191 192 /* 193 * Corner case: 52-bit VA capable systems running KVM in nVHE mode may 194 * be limited in their ability to support a linear map that exceeds 51 195 * bits of VA space, depending on the placement of the ID map. Given 196 * that the placement of the ID map may be randomized, let's simply 197 * limit the kernel's linear map to 51 bits as well if we detect this 198 * configuration. 199 */ 200 if (IS_ENABLED(CONFIG_KVM) && vabits_actual == 52 && 201 is_hyp_mode_available() && !is_kernel_in_hyp_mode()) { 202 pr_info("Capping linear region to 51 bits for KVM in nVHE mode on LVA capable hardware.\n"); 203 linear_region_size = min_t(u64, linear_region_size, BIT(51)); 204 } 205 206 /* Remove memory above our supported physical address size */ 207 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX); 208 209 /* 210 * Select a suitable value for the base of physical memory. 211 */ 212 memstart_addr = round_down(memblock_start_of_DRAM(), 213 ARM64_MEMSTART_ALIGN); 214 215 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size) 216 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n"); 217 218 /* 219 * Remove the memory that we will not be able to cover with the 220 * linear mapping. Take care not to clip the kernel which may be 221 * high in memory. 222 */ 223 memblock_remove(max_t(u64, memstart_addr + linear_region_size, 224 __pa_symbol(_end)), ULLONG_MAX); 225 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) { 226 /* ensure that memstart_addr remains sufficiently aligned */ 227 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size, 228 ARM64_MEMSTART_ALIGN); 229 memblock_remove(0, memstart_addr); 230 } 231 232 /* 233 * If we are running with a 52-bit kernel VA config on a system that 234 * does not support it, we have to place the available physical 235 * memory in the 48-bit addressable part of the linear region, i.e., 236 * we have to move it upward. Since memstart_addr represents the 237 * physical address of PAGE_OFFSET, we have to *subtract* from it. 238 */ 239 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52)) 240 memstart_addr -= _PAGE_OFFSET(vabits_actual) - _PAGE_OFFSET(52); 241 242 /* 243 * Apply the memory limit if it was set. Since the kernel may be loaded 244 * high up in memory, add back the kernel region that must be accessible 245 * via the linear mapping. 246 */ 247 if (memory_limit != PHYS_ADDR_MAX) { 248 memblock_mem_limit_remove_map(memory_limit); 249 memblock_add(__pa_symbol(_text), (u64)(_end - _text)); 250 } 251 252 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { 253 /* 254 * Add back the memory we just removed if it results in the 255 * initrd to become inaccessible via the linear mapping. 256 * Otherwise, this is a no-op 257 */ 258 u64 base = phys_initrd_start & PAGE_MASK; 259 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base; 260 261 /* 262 * We can only add back the initrd memory if we don't end up 263 * with more memory than we can address via the linear mapping. 264 * It is up to the bootloader to position the kernel and the 265 * initrd reasonably close to each other (i.e., within 32 GB of 266 * each other) so that all granule/#levels combinations can 267 * always access both. 268 */ 269 if (WARN(base < memblock_start_of_DRAM() || 270 base + size > memblock_start_of_DRAM() + 271 linear_region_size, 272 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) { 273 phys_initrd_size = 0; 274 } else { 275 memblock_add(base, size); 276 memblock_clear_nomap(base, size); 277 memblock_reserve(base, size); 278 } 279 } 280 281 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 282 extern u16 memstart_offset_seed; 283 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); 284 int parange = cpuid_feature_extract_unsigned_field( 285 mmfr0, ID_AA64MMFR0_EL1_PARANGE_SHIFT); 286 s64 range = linear_region_size - 287 BIT(id_aa64mmfr0_parange_to_phys_shift(parange)); 288 289 /* 290 * If the size of the linear region exceeds, by a sufficient 291 * margin, the size of the region that the physical memory can 292 * span, randomize the linear region as well. 293 */ 294 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) { 295 range /= ARM64_MEMSTART_ALIGN; 296 memstart_addr -= ARM64_MEMSTART_ALIGN * 297 ((range * memstart_offset_seed) >> 16); 298 } 299 } 300 301 /* 302 * Register the kernel text, kernel data, initrd, and initial 303 * pagetables with memblock. 304 */ 305 memblock_reserve(__pa_symbol(_stext), _end - _stext); 306 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { 307 /* the generic initrd code expects virtual addresses */ 308 initrd_start = __phys_to_virt(phys_initrd_start); 309 initrd_end = initrd_start + phys_initrd_size; 310 } 311 312 early_init_fdt_scan_reserved_mem(); 313 314 high_memory = __va(memblock_end_of_DRAM() - 1) + 1; 315 } 316 317 void __init bootmem_init(void) 318 { 319 unsigned long min, max; 320 321 min = PFN_UP(memblock_start_of_DRAM()); 322 max = PFN_DOWN(memblock_end_of_DRAM()); 323 324 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT); 325 326 max_pfn = max_low_pfn = max; 327 min_low_pfn = min; 328 329 arch_numa_init(); 330 331 /* 332 * must be done after arch_numa_init() which calls numa_init() to 333 * initialize node_online_map that gets used in hugetlb_cma_reserve() 334 * while allocating required CMA size across online nodes. 335 */ 336 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA) 337 arm64_hugetlb_cma_reserve(); 338 #endif 339 340 kvm_hyp_reserve(); 341 342 /* 343 * sparse_init() tries to allocate memory from memblock, so must be 344 * done after the fixed reservations 345 */ 346 sparse_init(); 347 zone_sizes_init(); 348 349 /* 350 * Reserve the CMA area after arm64_dma_phys_limit was initialised. 351 */ 352 dma_contiguous_reserve(arm64_dma_phys_limit); 353 354 /* 355 * request_standard_resources() depends on crashkernel's memory being 356 * reserved, so do it here. 357 */ 358 arch_reserve_crashkernel(); 359 360 memblock_dump_all(); 361 } 362 363 /* 364 * mem_init() marks the free areas in the mem_map and tells us how much memory 365 * is free. This is done after various parts of the system have claimed their 366 * memory after the kernel image. 367 */ 368 void __init mem_init(void) 369 { 370 unsigned int flags = SWIOTLB_VERBOSE; 371 bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); 372 373 if (is_realm_world()) { 374 swiotlb = true; 375 flags |= SWIOTLB_FORCE; 376 } 377 378 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) { 379 /* 380 * If no bouncing needed for ZONE_DMA, reduce the swiotlb 381 * buffer for kmalloc() bouncing to 1MB per 1GB of RAM. 382 */ 383 unsigned long size = 384 DIV_ROUND_UP(memblock_phys_mem_size(), 1024); 385 swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); 386 swiotlb = true; 387 } 388 389 swiotlb_init(swiotlb, flags); 390 swiotlb_update_mem_attributes(); 391 392 /* this will put all unused low memory onto the freelists */ 393 memblock_free_all(); 394 395 /* 396 * Check boundaries twice: Some fundamental inconsistencies can be 397 * detected at build time already. 398 */ 399 #ifdef CONFIG_COMPAT 400 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64); 401 #endif 402 403 /* 404 * Selected page table levels should match when derived from 405 * scratch using the virtual address range and page size. 406 */ 407 BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) != 408 CONFIG_PGTABLE_LEVELS); 409 410 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { 411 extern int sysctl_overcommit_memory; 412 /* 413 * On a machine this small we won't get anywhere without 414 * overcommit, so turn it on by default. 415 */ 416 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS; 417 } 418 } 419 420 void free_initmem(void) 421 { 422 void *lm_init_begin = lm_alias(__init_begin); 423 void *lm_init_end = lm_alias(__init_end); 424 425 WARN_ON(!IS_ALIGNED((unsigned long)lm_init_begin, PAGE_SIZE)); 426 WARN_ON(!IS_ALIGNED((unsigned long)lm_init_end, PAGE_SIZE)); 427 428 /* Delete __init region from memblock.reserved. */ 429 memblock_free(lm_init_begin, lm_init_end - lm_init_begin); 430 431 free_reserved_area(lm_init_begin, lm_init_end, 432 POISON_FREE_INITMEM, "unused kernel"); 433 /* 434 * Unmap the __init region but leave the VM area in place. This 435 * prevents the region from being reused for kernel modules, which 436 * is not supported by kallsyms. 437 */ 438 vunmap_range((u64)__init_begin, (u64)__init_end); 439 } 440 441 void dump_mem_limit(void) 442 { 443 if (memory_limit != PHYS_ADDR_MAX) { 444 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20); 445 } else { 446 pr_emerg("Memory Limit: none\n"); 447 } 448 } 449 450 #ifdef CONFIG_EXECMEM 451 static u64 module_direct_base __ro_after_init = 0; 452 static u64 module_plt_base __ro_after_init = 0; 453 454 /* 455 * Choose a random page-aligned base address for a window of 'size' bytes which 456 * entirely contains the interval [start, end - 1]. 457 */ 458 static u64 __init random_bounding_box(u64 size, u64 start, u64 end) 459 { 460 u64 max_pgoff, pgoff; 461 462 if ((end - start) >= size) 463 return 0; 464 465 max_pgoff = (size - (end - start)) / PAGE_SIZE; 466 pgoff = get_random_u32_inclusive(0, max_pgoff); 467 468 return start - pgoff * PAGE_SIZE; 469 } 470 471 /* 472 * Modules may directly reference data and text anywhere within the kernel 473 * image and other modules. References using PREL32 relocations have a +/-2G 474 * range, and so we need to ensure that the entire kernel image and all modules 475 * fall within a 2G window such that these are always within range. 476 * 477 * Modules may directly branch to functions and code within the kernel text, 478 * and to functions and code within other modules. These branches will use 479 * CALL26/JUMP26 relocations with a +/-128M range. Without PLTs, we must ensure 480 * that the entire kernel text and all module text falls within a 128M window 481 * such that these are always within range. With PLTs, we can expand this to a 482 * 2G window. 483 * 484 * We chose the 128M region to surround the entire kernel image (rather than 485 * just the text) as using the same bounds for the 128M and 2G regions ensures 486 * by construction that we never select a 128M region that is not a subset of 487 * the 2G region. For very large and unusual kernel configurations this means 488 * we may fall back to PLTs where they could have been avoided, but this keeps 489 * the logic significantly simpler. 490 */ 491 static int __init module_init_limits(void) 492 { 493 u64 kernel_end = (u64)_end; 494 u64 kernel_start = (u64)_text; 495 u64 kernel_size = kernel_end - kernel_start; 496 497 /* 498 * The default modules region is placed immediately below the kernel 499 * image, and is large enough to use the full 2G relocation range. 500 */ 501 BUILD_BUG_ON(KIMAGE_VADDR != MODULES_END); 502 BUILD_BUG_ON(MODULES_VSIZE < SZ_2G); 503 504 if (!kaslr_enabled()) { 505 if (kernel_size < SZ_128M) 506 module_direct_base = kernel_end - SZ_128M; 507 if (kernel_size < SZ_2G) 508 module_plt_base = kernel_end - SZ_2G; 509 } else { 510 u64 min = kernel_start; 511 u64 max = kernel_end; 512 513 if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) { 514 pr_info("2G module region forced by RANDOMIZE_MODULE_REGION_FULL\n"); 515 } else { 516 module_direct_base = random_bounding_box(SZ_128M, min, max); 517 if (module_direct_base) { 518 min = module_direct_base; 519 max = module_direct_base + SZ_128M; 520 } 521 } 522 523 module_plt_base = random_bounding_box(SZ_2G, min, max); 524 } 525 526 pr_info("%llu pages in range for non-PLT usage", 527 module_direct_base ? (SZ_128M - kernel_size) / PAGE_SIZE : 0); 528 pr_info("%llu pages in range for PLT usage", 529 module_plt_base ? (SZ_2G - kernel_size) / PAGE_SIZE : 0); 530 531 return 0; 532 } 533 534 static struct execmem_info execmem_info __ro_after_init; 535 536 struct execmem_info __init *execmem_arch_setup(void) 537 { 538 unsigned long fallback_start = 0, fallback_end = 0; 539 unsigned long start = 0, end = 0; 540 541 module_init_limits(); 542 543 /* 544 * Where possible, prefer to allocate within direct branch range of the 545 * kernel such that no PLTs are necessary. 546 */ 547 if (module_direct_base) { 548 start = module_direct_base; 549 end = module_direct_base + SZ_128M; 550 551 if (module_plt_base) { 552 fallback_start = module_plt_base; 553 fallback_end = module_plt_base + SZ_2G; 554 } 555 } else if (module_plt_base) { 556 start = module_plt_base; 557 end = module_plt_base + SZ_2G; 558 } 559 560 execmem_info = (struct execmem_info){ 561 .ranges = { 562 [EXECMEM_DEFAULT] = { 563 .start = start, 564 .end = end, 565 .pgprot = PAGE_KERNEL, 566 .alignment = 1, 567 .fallback_start = fallback_start, 568 .fallback_end = fallback_end, 569 }, 570 [EXECMEM_KPROBES] = { 571 .start = VMALLOC_START, 572 .end = VMALLOC_END, 573 .pgprot = PAGE_KERNEL_ROX, 574 .alignment = 1, 575 }, 576 [EXECMEM_BPF] = { 577 .start = VMALLOC_START, 578 .end = VMALLOC_END, 579 .pgprot = PAGE_KERNEL, 580 .alignment = 1, 581 }, 582 }, 583 }; 584 585 return &execmem_info; 586 } 587 #endif /* CONFIG_EXECMEM */ 588