1 // SPDX-License-Identifier: GPL-2.0-only
3 * Based on arch/arm/mm/init.c
5 * Copyright (C) 1995-2005 Russell King
6 * Copyright (C) 2012 ARM Ltd.
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>
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>
29 #include <linux/kexec.h>
30 #include <linux/crash_dump.h>
31 #include <linux/hugetlb.h>
32 #include <linux/acpi_iort.h>
35 #include <asm/fixmap.h>
36 #include <asm/kasan.h>
37 #include <asm/kernel-pgtable.h>
38 #include <asm/memory.h>
40 #include <asm/sections.h>
41 #include <asm/setup.h>
42 #include <linux/sizes.h>
44 #include <asm/alternative.h>
47 * We need to be able to catch inadvertent references to memstart_addr
48 * that occur (potentially in generic code) before arm64_memblock_init()
49 * executes, which assigns it its actual value. So use a default value
50 * that cannot be mistaken for a real physical address.
52 s64 memstart_addr __ro_after_init = -1;
53 EXPORT_SYMBOL(memstart_addr);
56 * If the corresponding config options are enabled, we create both ZONE_DMA
57 * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory
58 * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4).
59 * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory,
60 * otherwise it is empty.
62 phys_addr_t arm64_dma_phys_limit __ro_after_init;
64 #ifdef CONFIG_KEXEC_CORE
66 * reserve_crashkernel() - reserves memory for crash kernel
68 * This function reserves memory area given in "crashkernel=" kernel command
69 * line parameter. The memory reserved is used by dump capture kernel when
70 * primary kernel is crashing.
72 static void __init reserve_crashkernel(void)
74 unsigned long long crash_base, crash_size;
77 ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
78 &crash_size, &crash_base);
79 /* no crashkernel= or invalid value specified */
80 if (ret || !crash_size)
83 crash_size = PAGE_ALIGN(crash_size);
85 if (crash_base == 0) {
86 /* Current arm64 boot protocol requires 2MB alignment */
87 crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
89 if (crash_base == 0) {
90 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
95 /* User specifies base address explicitly. */
96 if (!memblock_is_region_memory(crash_base, crash_size)) {
97 pr_warn("cannot reserve crashkernel: region is not memory\n");
101 if (memblock_is_region_reserved(crash_base, crash_size)) {
102 pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
106 if (!IS_ALIGNED(crash_base, SZ_2M)) {
107 pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
111 memblock_reserve(crash_base, crash_size);
113 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
114 crash_base, crash_base + crash_size, crash_size >> 20);
116 crashk_res.start = crash_base;
117 crashk_res.end = crash_base + crash_size - 1;
120 static void __init reserve_crashkernel(void)
123 #endif /* CONFIG_KEXEC_CORE */
125 #ifdef CONFIG_CRASH_DUMP
126 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
127 const char *uname, int depth, void *data)
132 if (depth != 1 || strcmp(uname, "chosen") != 0)
135 reg = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
136 if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
139 elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, ®);
140 elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, ®);
146 * reserve_elfcorehdr() - reserves memory for elf core header
148 * This function reserves the memory occupied by an elf core header
149 * described in the device tree. This region contains all the
150 * information about primary kernel's core image and is used by a dump
151 * capture kernel to access the system memory on primary kernel.
153 static void __init reserve_elfcorehdr(void)
155 of_scan_flat_dt(early_init_dt_scan_elfcorehdr, NULL);
157 if (!elfcorehdr_size)
160 if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
161 pr_warn("elfcorehdr is overlapped\n");
165 memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
167 pr_info("Reserving %lldKB of memory at 0x%llx for elfcorehdr\n",
168 elfcorehdr_size >> 10, elfcorehdr_addr);
171 static void __init reserve_elfcorehdr(void)
174 #endif /* CONFIG_CRASH_DUMP */
177 * Return the maximum physical address for a zone accessible by the given bits
178 * limit. If DRAM starts above 32-bit, expand the zone to the maximum
179 * available memory, otherwise cap it at 32-bit.
181 static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
183 phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits);
184 phys_addr_t phys_start = memblock_start_of_DRAM();
186 if (phys_start > U32_MAX)
187 zone_mask = PHYS_ADDR_MAX;
188 else if (phys_start > zone_mask)
191 return min(zone_mask, memblock_end_of_DRAM() - 1) + 1;
194 static void __init zone_sizes_init(unsigned long min, unsigned long max)
196 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
197 unsigned int __maybe_unused acpi_zone_dma_bits;
198 unsigned int __maybe_unused dt_zone_dma_bits;
199 phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32);
201 #ifdef CONFIG_ZONE_DMA
202 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address());
203 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
204 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits);
205 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
206 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
208 #ifdef CONFIG_ZONE_DMA32
209 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit);
210 if (!arm64_dma_phys_limit)
211 arm64_dma_phys_limit = dma32_phys_limit;
213 if (!arm64_dma_phys_limit)
214 arm64_dma_phys_limit = PHYS_MASK + 1;
215 max_zone_pfns[ZONE_NORMAL] = max;
217 free_area_init(max_zone_pfns);
220 int pfn_valid(unsigned long pfn)
222 phys_addr_t addr = PFN_PHYS(pfn);
225 * Ensure the upper PAGE_SHIFT bits are clear in the
226 * pfn. Else it might lead to false positives when
227 * some of the upper bits are set, but the lower bits
230 if (PHYS_PFN(addr) != pfn)
233 #ifdef CONFIG_SPARSEMEM
235 struct mem_section *ms;
237 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
240 ms = __pfn_to_section(pfn);
241 if (!valid_section(ms))
245 * ZONE_DEVICE memory does not have the memblock entries.
246 * memblock_is_map_memory() check for ZONE_DEVICE based
247 * addresses will always fail. Even the normal hotplugged
248 * memory will never have MEMBLOCK_NOMAP flag set in their
249 * memblock entries. Skip memblock search for all non early
250 * memory sections covering all of hotplug memory including
251 * both normal and ZONE_DEVICE based.
253 if (!early_section(ms))
254 return pfn_section_valid(ms, pfn);
257 return memblock_is_map_memory(addr);
259 EXPORT_SYMBOL(pfn_valid);
261 static phys_addr_t memory_limit = PHYS_ADDR_MAX;
264 * Limit the memory size that was specified via FDT.
266 static int __init early_mem(char *p)
271 memory_limit = memparse(p, &p) & PAGE_MASK;
272 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20);
276 early_param("mem", early_mem);
278 static int __init early_init_dt_scan_usablemem(unsigned long node,
279 const char *uname, int depth, void *data)
281 struct memblock_region *usablemem = data;
285 if (depth != 1 || strcmp(uname, "chosen") != 0)
288 reg = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
289 if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
292 usablemem->base = dt_mem_next_cell(dt_root_addr_cells, ®);
293 usablemem->size = dt_mem_next_cell(dt_root_size_cells, ®);
298 static void __init fdt_enforce_memory_region(void)
300 struct memblock_region reg = {
304 of_scan_flat_dt(early_init_dt_scan_usablemem, ®);
307 memblock_cap_memory_range(reg.base, reg.size);
310 void __init arm64_memblock_init(void)
312 const s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual);
314 /* Handle linux,usable-memory-range property */
315 fdt_enforce_memory_region();
317 /* Remove memory above our supported physical address size */
318 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);
321 * Select a suitable value for the base of physical memory.
323 memstart_addr = round_down(memblock_start_of_DRAM(),
324 ARM64_MEMSTART_ALIGN);
326 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size)
327 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n");
330 * Remove the memory that we will not be able to cover with the
331 * linear mapping. Take care not to clip the kernel which may be
334 memblock_remove(max_t(u64, memstart_addr + linear_region_size,
335 __pa_symbol(_end)), ULLONG_MAX);
336 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {
337 /* ensure that memstart_addr remains sufficiently aligned */
338 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size,
339 ARM64_MEMSTART_ALIGN);
340 memblock_remove(0, memstart_addr);
344 * If we are running with a 52-bit kernel VA config on a system that
345 * does not support it, we have to place the available physical
346 * memory in the 48-bit addressable part of the linear region, i.e.,
347 * we have to move it upward. Since memstart_addr represents the
348 * physical address of PAGE_OFFSET, we have to *subtract* from it.
350 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52))
351 memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52);
354 * Apply the memory limit if it was set. Since the kernel may be loaded
355 * high up in memory, add back the kernel region that must be accessible
356 * via the linear mapping.
358 if (memory_limit != PHYS_ADDR_MAX) {
359 memblock_mem_limit_remove_map(memory_limit);
360 memblock_add(__pa_symbol(_text), (u64)(_end - _text));
363 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
365 * Add back the memory we just removed if it results in the
366 * initrd to become inaccessible via the linear mapping.
367 * Otherwise, this is a no-op
369 u64 base = phys_initrd_start & PAGE_MASK;
370 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
373 * We can only add back the initrd memory if we don't end up
374 * with more memory than we can address via the linear mapping.
375 * It is up to the bootloader to position the kernel and the
376 * initrd reasonably close to each other (i.e., within 32 GB of
377 * each other) so that all granule/#levels combinations can
378 * always access both.
380 if (WARN(base < memblock_start_of_DRAM() ||
381 base + size > memblock_start_of_DRAM() +
383 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
384 phys_initrd_size = 0;
386 memblock_remove(base, size); /* clear MEMBLOCK_ flags */
387 memblock_add(base, size);
388 memblock_reserve(base, size);
392 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
393 extern u16 memstart_offset_seed;
394 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
395 int parange = cpuid_feature_extract_unsigned_field(
396 mmfr0, ID_AA64MMFR0_PARANGE_SHIFT);
397 s64 range = linear_region_size -
398 BIT(id_aa64mmfr0_parange_to_phys_shift(parange));
401 * If the size of the linear region exceeds, by a sufficient
402 * margin, the size of the region that the physical memory can
403 * span, randomize the linear region as well.
405 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) {
406 range /= ARM64_MEMSTART_ALIGN;
407 memstart_addr -= ARM64_MEMSTART_ALIGN *
408 ((range * memstart_offset_seed) >> 16);
413 * Register the kernel text, kernel data, initrd, and initial
414 * pagetables with memblock.
416 memblock_reserve(__pa_symbol(_stext), _end - _stext);
417 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
418 /* the generic initrd code expects virtual addresses */
419 initrd_start = __phys_to_virt(phys_initrd_start);
420 initrd_end = initrd_start + phys_initrd_size;
423 early_init_fdt_scan_reserved_mem();
425 reserve_elfcorehdr();
427 high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
430 void __init bootmem_init(void)
432 unsigned long min, max;
434 min = PFN_UP(memblock_start_of_DRAM());
435 max = PFN_DOWN(memblock_end_of_DRAM());
437 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
439 max_pfn = max_low_pfn = max;
445 * must be done after arch_numa_init() which calls numa_init() to
446 * initialize node_online_map that gets used in hugetlb_cma_reserve()
447 * while allocating required CMA size across online nodes.
449 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
450 arm64_hugetlb_cma_reserve();
453 dma_pernuma_cma_reserve();
456 * sparse_init() tries to allocate memory from memblock, so must be
457 * done after the fixed reservations
460 zone_sizes_init(min, max);
463 * Reserve the CMA area after arm64_dma_phys_limit was initialised.
465 dma_contiguous_reserve(arm64_dma_phys_limit);
468 * request_standard_resources() depends on crashkernel's memory being
469 * reserved, so do it here.
471 reserve_crashkernel();
477 * mem_init() marks the free areas in the mem_map and tells us how much memory
478 * is free. This is done after various parts of the system have claimed their
479 * memory after the kernel image.
481 void __init mem_init(void)
483 if (swiotlb_force == SWIOTLB_FORCE ||
484 max_pfn > PFN_DOWN(arm64_dma_phys_limit))
487 swiotlb_force = SWIOTLB_NO_FORCE;
489 set_max_mapnr(max_pfn - PHYS_PFN_OFFSET);
491 /* this will put all unused low memory onto the freelists */
494 mem_init_print_info(NULL);
497 * Check boundaries twice: Some fundamental inconsistencies can be
498 * detected at build time already.
501 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64);
504 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
505 extern int sysctl_overcommit_memory;
507 * On a machine this small we won't get anywhere without
508 * overcommit, so turn it on by default.
510 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
514 void free_initmem(void)
516 free_reserved_area(lm_alias(__init_begin),
517 lm_alias(__init_end),
518 POISON_FREE_INITMEM, "unused kernel");
520 * Unmap the __init region but leave the VM area in place. This
521 * prevents the region from being reused for kernel modules, which
522 * is not supported by kallsyms.
524 unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
527 void dump_mem_limit(void)
529 if (memory_limit != PHYS_ADDR_MAX) {
530 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20);
532 pr_emerg("Memory Limit: none\n");