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 36 #include <asm/boot.h> 37 #include <asm/fixmap.h> 38 #include <asm/kasan.h> 39 #include <asm/kernel-pgtable.h> 40 #include <asm/kvm_host.h> 41 #include <asm/memory.h> 42 #include <asm/numa.h> 43 #include <asm/sections.h> 44 #include <asm/setup.h> 45 #include <linux/sizes.h> 46 #include <asm/tlb.h> 47 #include <asm/alternative.h> 48 #include <asm/xen/swiotlb-xen.h> 49 50 /* 51 * We need to be able to catch inadvertent references to memstart_addr 52 * that occur (potentially in generic code) before arm64_memblock_init() 53 * executes, which assigns it its actual value. So use a default value 54 * that cannot be mistaken for a real physical address. 55 */ 56 s64 memstart_addr __ro_after_init = -1; 57 EXPORT_SYMBOL(memstart_addr); 58 59 /* 60 * If the corresponding config options are enabled, we create both ZONE_DMA 61 * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory 62 * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4). 63 * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory, 64 * otherwise it is empty. 65 */ 66 phys_addr_t __ro_after_init arm64_dma_phys_limit; 67 68 /* 69 * To make optimal use of block mappings when laying out the linear 70 * mapping, round down the base of physical memory to a size that can 71 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE 72 * (64k granule), or a multiple that can be mapped using contiguous bits 73 * in the page tables: 32 * PMD_SIZE (16k granule) 74 */ 75 #if defined(CONFIG_ARM64_4K_PAGES) 76 #define ARM64_MEMSTART_SHIFT PUD_SHIFT 77 #elif defined(CONFIG_ARM64_16K_PAGES) 78 #define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT 79 #else 80 #define ARM64_MEMSTART_SHIFT PMD_SHIFT 81 #endif 82 83 /* 84 * sparsemem vmemmap imposes an additional requirement on the alignment of 85 * memstart_addr, due to the fact that the base of the vmemmap region 86 * has a direct correspondence, and needs to appear sufficiently aligned 87 * in the virtual address space. 88 */ 89 #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS 90 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) 91 #else 92 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) 93 #endif 94 95 static void __init arch_reserve_crashkernel(void) 96 { 97 unsigned long long low_size = 0; 98 unsigned long long crash_base, crash_size; 99 char *cmdline = boot_command_line; 100 bool high = false; 101 int ret; 102 103 if (!IS_ENABLED(CONFIG_CRASH_RESERVE)) 104 return; 105 106 ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), 107 &crash_size, &crash_base, 108 &low_size, &high); 109 if (ret) 110 return; 111 112 reserve_crashkernel_generic(cmdline, crash_size, crash_base, 113 low_size, high); 114 } 115 116 /* 117 * Return the maximum physical address for a zone accessible by the given bits 118 * limit. If DRAM starts above 32-bit, expand the zone to the maximum 119 * available memory, otherwise cap it at 32-bit. 120 */ 121 static phys_addr_t __init max_zone_phys(unsigned int zone_bits) 122 { 123 phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits); 124 phys_addr_t phys_start = memblock_start_of_DRAM(); 125 126 if (phys_start > U32_MAX) 127 zone_mask = PHYS_ADDR_MAX; 128 else if (phys_start > zone_mask) 129 zone_mask = U32_MAX; 130 131 return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; 132 } 133 134 static void __init zone_sizes_init(void) 135 { 136 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; 137 unsigned int __maybe_unused acpi_zone_dma_bits; 138 unsigned int __maybe_unused dt_zone_dma_bits; 139 phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32); 140 141 #ifdef CONFIG_ZONE_DMA 142 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); 143 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL)); 144 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); 145 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits); 146 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit); 147 #endif 148 #ifdef CONFIG_ZONE_DMA32 149 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); 150 if (!arm64_dma_phys_limit) 151 arm64_dma_phys_limit = dma32_phys_limit; 152 #endif 153 if (!arm64_dma_phys_limit) 154 arm64_dma_phys_limit = PHYS_MASK + 1; 155 max_zone_pfns[ZONE_NORMAL] = max_pfn; 156 157 free_area_init(max_zone_pfns); 158 } 159 160 int pfn_is_map_memory(unsigned long pfn) 161 { 162 phys_addr_t addr = PFN_PHYS(pfn); 163 164 /* avoid false positives for bogus PFNs, see comment in pfn_valid() */ 165 if (PHYS_PFN(addr) != pfn) 166 return 0; 167 168 return memblock_is_map_memory(addr); 169 } 170 EXPORT_SYMBOL(pfn_is_map_memory); 171 172 static phys_addr_t memory_limit __ro_after_init = PHYS_ADDR_MAX; 173 174 /* 175 * Limit the memory size that was specified via FDT. 176 */ 177 static int __init early_mem(char *p) 178 { 179 if (!p) 180 return 1; 181 182 memory_limit = memparse(p, &p) & PAGE_MASK; 183 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); 184 185 return 0; 186 } 187 early_param("mem", early_mem); 188 189 void __init arm64_memblock_init(void) 190 { 191 s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); 192 193 /* 194 * Corner case: 52-bit VA capable systems running KVM in nVHE mode may 195 * be limited in their ability to support a linear map that exceeds 51 196 * bits of VA space, depending on the placement of the ID map. Given 197 * that the placement of the ID map may be randomized, let's simply 198 * limit the kernel's linear map to 51 bits as well if we detect this 199 * configuration. 200 */ 201 if (IS_ENABLED(CONFIG_KVM) && vabits_actual == 52 && 202 is_hyp_mode_available() && !is_kernel_in_hyp_mode()) { 203 pr_info("Capping linear region to 51 bits for KVM in nVHE mode on LVA capable hardware.\n"); 204 linear_region_size = min_t(u64, linear_region_size, BIT(51)); 205 } 206 207 /* Remove memory above our supported physical address size */ 208 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX); 209 210 /* 211 * Select a suitable value for the base of physical memory. 212 */ 213 memstart_addr = round_down(memblock_start_of_DRAM(), 214 ARM64_MEMSTART_ALIGN); 215 216 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size) 217 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n"); 218 219 /* 220 * Remove the memory that we will not be able to cover with the 221 * linear mapping. Take care not to clip the kernel which may be 222 * high in memory. 223 */ 224 memblock_remove(max_t(u64, memstart_addr + linear_region_size, 225 __pa_symbol(_end)), ULLONG_MAX); 226 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) { 227 /* ensure that memstart_addr remains sufficiently aligned */ 228 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size, 229 ARM64_MEMSTART_ALIGN); 230 memblock_remove(0, memstart_addr); 231 } 232 233 /* 234 * If we are running with a 52-bit kernel VA config on a system that 235 * does not support it, we have to place the available physical 236 * memory in the 48-bit addressable part of the linear region, i.e., 237 * we have to move it upward. Since memstart_addr represents the 238 * physical address of PAGE_OFFSET, we have to *subtract* from it. 239 */ 240 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52)) 241 memstart_addr -= _PAGE_OFFSET(vabits_actual) - _PAGE_OFFSET(52); 242 243 /* 244 * Apply the memory limit if it was set. Since the kernel may be loaded 245 * high up in memory, add back the kernel region that must be accessible 246 * via the linear mapping. 247 */ 248 if (memory_limit != PHYS_ADDR_MAX) { 249 memblock_mem_limit_remove_map(memory_limit); 250 memblock_add(__pa_symbol(_text), (u64)(_end - _text)); 251 } 252 253 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { 254 /* 255 * Add back the memory we just removed if it results in the 256 * initrd to become inaccessible via the linear mapping. 257 * Otherwise, this is a no-op 258 */ 259 u64 base = phys_initrd_start & PAGE_MASK; 260 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base; 261 262 /* 263 * We can only add back the initrd memory if we don't end up 264 * with more memory than we can address via the linear mapping. 265 * It is up to the bootloader to position the kernel and the 266 * initrd reasonably close to each other (i.e., within 32 GB of 267 * each other) so that all granule/#levels combinations can 268 * always access both. 269 */ 270 if (WARN(base < memblock_start_of_DRAM() || 271 base + size > memblock_start_of_DRAM() + 272 linear_region_size, 273 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) { 274 phys_initrd_size = 0; 275 } else { 276 memblock_add(base, size); 277 memblock_clear_nomap(base, size); 278 memblock_reserve(base, size); 279 } 280 } 281 282 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 283 extern u16 memstart_offset_seed; 284 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); 285 int parange = cpuid_feature_extract_unsigned_field( 286 mmfr0, ID_AA64MMFR0_EL1_PARANGE_SHIFT); 287 s64 range = linear_region_size - 288 BIT(id_aa64mmfr0_parange_to_phys_shift(parange)); 289 290 /* 291 * If the size of the linear region exceeds, by a sufficient 292 * margin, the size of the region that the physical memory can 293 * span, randomize the linear region as well. 294 */ 295 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) { 296 range /= ARM64_MEMSTART_ALIGN; 297 memstart_addr -= ARM64_MEMSTART_ALIGN * 298 ((range * memstart_offset_seed) >> 16); 299 } 300 } 301 302 /* 303 * Register the kernel text, kernel data, initrd, and initial 304 * pagetables with memblock. 305 */ 306 memblock_reserve(__pa_symbol(_stext), _end - _stext); 307 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { 308 /* the generic initrd code expects virtual addresses */ 309 initrd_start = __phys_to_virt(phys_initrd_start); 310 initrd_end = initrd_start + phys_initrd_size; 311 } 312 313 early_init_fdt_scan_reserved_mem(); 314 315 high_memory = __va(memblock_end_of_DRAM() - 1) + 1; 316 } 317 318 void __init bootmem_init(void) 319 { 320 unsigned long min, max; 321 322 min = PFN_UP(memblock_start_of_DRAM()); 323 max = PFN_DOWN(memblock_end_of_DRAM()); 324 325 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT); 326 327 max_pfn = max_low_pfn = max; 328 min_low_pfn = min; 329 330 arch_numa_init(); 331 332 /* 333 * must be done after arch_numa_init() which calls numa_init() to 334 * initialize node_online_map that gets used in hugetlb_cma_reserve() 335 * while allocating required CMA size across online nodes. 336 */ 337 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA) 338 arm64_hugetlb_cma_reserve(); 339 #endif 340 341 kvm_hyp_reserve(); 342 343 /* 344 * sparse_init() tries to allocate memory from memblock, so must be 345 * done after the fixed reservations 346 */ 347 sparse_init(); 348 zone_sizes_init(); 349 350 /* 351 * Reserve the CMA area after arm64_dma_phys_limit was initialised. 352 */ 353 dma_contiguous_reserve(arm64_dma_phys_limit); 354 355 /* 356 * request_standard_resources() depends on crashkernel's memory being 357 * reserved, so do it here. 358 */ 359 arch_reserve_crashkernel(); 360 361 memblock_dump_all(); 362 } 363 364 /* 365 * mem_init() marks the free areas in the mem_map and tells us how much memory 366 * is free. This is done after various parts of the system have claimed their 367 * memory after the kernel image. 368 */ 369 void __init mem_init(void) 370 { 371 bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); 372 373 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) { 374 /* 375 * If no bouncing needed for ZONE_DMA, reduce the swiotlb 376 * buffer for kmalloc() bouncing to 1MB per 1GB of RAM. 377 */ 378 unsigned long size = 379 DIV_ROUND_UP(memblock_phys_mem_size(), 1024); 380 swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); 381 swiotlb = true; 382 } 383 384 swiotlb_init(swiotlb, SWIOTLB_VERBOSE); 385 386 /* this will put all unused low memory onto the freelists */ 387 memblock_free_all(); 388 389 /* 390 * Check boundaries twice: Some fundamental inconsistencies can be 391 * detected at build time already. 392 */ 393 #ifdef CONFIG_COMPAT 394 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64); 395 #endif 396 397 /* 398 * Selected page table levels should match when derived from 399 * scratch using the virtual address range and page size. 400 */ 401 BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) != 402 CONFIG_PGTABLE_LEVELS); 403 404 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { 405 extern int sysctl_overcommit_memory; 406 /* 407 * On a machine this small we won't get anywhere without 408 * overcommit, so turn it on by default. 409 */ 410 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS; 411 } 412 } 413 414 void free_initmem(void) 415 { 416 free_reserved_area(lm_alias(__init_begin), 417 lm_alias(__init_end), 418 POISON_FREE_INITMEM, "unused kernel"); 419 /* 420 * Unmap the __init region but leave the VM area in place. This 421 * prevents the region from being reused for kernel modules, which 422 * is not supported by kallsyms. 423 */ 424 vunmap_range((u64)__init_begin, (u64)__init_end); 425 } 426 427 void dump_mem_limit(void) 428 { 429 if (memory_limit != PHYS_ADDR_MAX) { 430 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20); 431 } else { 432 pr_emerg("Memory Limit: none\n"); 433 } 434 } 435