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/memblock.h> 20 #include <linux/sort.h> 21 #include <linux/of.h> 22 #include <linux/of_fdt.h> 23 #include <linux/dma-direct.h> 24 #include <linux/dma-map-ops.h> 25 #include <linux/efi.h> 26 #include <linux/swiotlb.h> 27 #include <linux/vmalloc.h> 28 #include <linux/mm.h> 29 #include <linux/kexec.h> 30 #include <linux/crash_dump.h> 31 #include <linux/hugetlb.h> 32 #include <linux/acpi_iort.h> 33 #include <linux/kmemleak.h> 34 35 #include <asm/boot.h> 36 #include <asm/fixmap.h> 37 #include <asm/kasan.h> 38 #include <asm/kernel-pgtable.h> 39 #include <asm/kvm_host.h> 40 #include <asm/memory.h> 41 #include <asm/numa.h> 42 #include <asm/sections.h> 43 #include <asm/setup.h> 44 #include <linux/sizes.h> 45 #include <asm/tlb.h> 46 #include <asm/alternative.h> 47 #include <asm/xen/swiotlb-xen.h> 48 49 /* 50 * We need to be able to catch inadvertent references to memstart_addr 51 * that occur (potentially in generic code) before arm64_memblock_init() 52 * executes, which assigns it its actual value. So use a default value 53 * that cannot be mistaken for a real physical address. 54 */ 55 s64 memstart_addr __ro_after_init = -1; 56 EXPORT_SYMBOL(memstart_addr); 57 58 /* 59 * If the corresponding config options are enabled, we create both ZONE_DMA 60 * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory 61 * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4). 62 * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory, 63 * otherwise it is empty. 64 */ 65 phys_addr_t __ro_after_init arm64_dma_phys_limit; 66 67 /* 68 * To make optimal use of block mappings when laying out the linear 69 * mapping, round down the base of physical memory to a size that can 70 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE 71 * (64k granule), or a multiple that can be mapped using contiguous bits 72 * in the page tables: 32 * PMD_SIZE (16k granule) 73 */ 74 #if defined(CONFIG_ARM64_4K_PAGES) 75 #define ARM64_MEMSTART_SHIFT PUD_SHIFT 76 #elif defined(CONFIG_ARM64_16K_PAGES) 77 #define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT 78 #else 79 #define ARM64_MEMSTART_SHIFT PMD_SHIFT 80 #endif 81 82 /* 83 * sparsemem vmemmap imposes an additional requirement on the alignment of 84 * memstart_addr, due to the fact that the base of the vmemmap region 85 * has a direct correspondence, and needs to appear sufficiently aligned 86 * in the virtual address space. 87 */ 88 #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS 89 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) 90 #else 91 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) 92 #endif 93 94 static void __init arch_reserve_crashkernel(void) 95 { 96 unsigned long long low_size = 0; 97 unsigned long long crash_base, crash_size; 98 char *cmdline = boot_command_line; 99 bool high = false; 100 int ret; 101 102 if (!IS_ENABLED(CONFIG_KEXEC_CORE)) 103 return; 104 105 ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), 106 &crash_size, &crash_base, 107 &low_size, &high); 108 if (ret) 109 return; 110 111 reserve_crashkernel_generic(cmdline, crash_size, crash_base, 112 low_size, high); 113 } 114 115 /* 116 * Return the maximum physical address for a zone accessible by the given bits 117 * limit. If DRAM starts above 32-bit, expand the zone to the maximum 118 * available memory, otherwise cap it at 32-bit. 119 */ 120 static phys_addr_t __init max_zone_phys(unsigned int zone_bits) 121 { 122 phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits); 123 phys_addr_t phys_start = memblock_start_of_DRAM(); 124 125 if (phys_start > U32_MAX) 126 zone_mask = PHYS_ADDR_MAX; 127 else if (phys_start > zone_mask) 128 zone_mask = U32_MAX; 129 130 return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; 131 } 132 133 static void __init zone_sizes_init(void) 134 { 135 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; 136 unsigned int __maybe_unused acpi_zone_dma_bits; 137 unsigned int __maybe_unused dt_zone_dma_bits; 138 phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32); 139 140 #ifdef CONFIG_ZONE_DMA 141 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); 142 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL)); 143 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); 144 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits); 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(48) - _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 bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); 371 372 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC)) 373 swiotlb = true; 374 375 swiotlb_init(swiotlb, SWIOTLB_VERBOSE); 376 377 /* this will put all unused low memory onto the freelists */ 378 memblock_free_all(); 379 380 /* 381 * Check boundaries twice: Some fundamental inconsistencies can be 382 * detected at build time already. 383 */ 384 #ifdef CONFIG_COMPAT 385 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64); 386 #endif 387 388 /* 389 * Selected page table levels should match when derived from 390 * scratch using the virtual address range and page size. 391 */ 392 BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) != 393 CONFIG_PGTABLE_LEVELS); 394 395 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { 396 extern int sysctl_overcommit_memory; 397 /* 398 * On a machine this small we won't get anywhere without 399 * overcommit, so turn it on by default. 400 */ 401 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS; 402 } 403 } 404 405 void free_initmem(void) 406 { 407 free_reserved_area(lm_alias(__init_begin), 408 lm_alias(__init_end), 409 POISON_FREE_INITMEM, "unused kernel"); 410 /* 411 * Unmap the __init region but leave the VM area in place. This 412 * prevents the region from being reused for kernel modules, which 413 * is not supported by kallsyms. 414 */ 415 vunmap_range((u64)__init_begin, (u64)__init_end); 416 } 417 418 void dump_mem_limit(void) 419 { 420 if (memory_limit != PHYS_ADDR_MAX) { 421 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20); 422 } else { 423 pr_emerg("Memory Limit: none\n"); 424 } 425 } 426