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 * We create both ZONE_DMA and ZONE_DMA32. ZONE_DMA covers the first 1G of
57 * memory as some devices, namely the Raspberry Pi 4, have peripherals with
58 * this limited view of the memory. ZONE_DMA32 will cover the rest of the 32
59 * bit addressable memory area.
61 phys_addr_t arm64_dma_phys_limit __ro_after_init;
62 static phys_addr_t arm64_dma32_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_dma32_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;
200 #ifdef CONFIG_ZONE_DMA
201 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address());
202 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
203 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits);
204 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
205 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
207 #ifdef CONFIG_ZONE_DMA32
208 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(arm64_dma32_phys_limit);
210 max_zone_pfns[ZONE_NORMAL] = max;
212 free_area_init(max_zone_pfns);
215 int pfn_valid(unsigned long pfn)
217 phys_addr_t addr = pfn << PAGE_SHIFT;
219 if ((addr >> PAGE_SHIFT) != pfn)
222 #ifdef CONFIG_SPARSEMEM
223 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
226 if (!valid_section(__pfn_to_section(pfn)))
229 return memblock_is_map_memory(addr);
231 EXPORT_SYMBOL(pfn_valid);
233 static phys_addr_t memory_limit = PHYS_ADDR_MAX;
236 * Limit the memory size that was specified via FDT.
238 static int __init early_mem(char *p)
243 memory_limit = memparse(p, &p) & PAGE_MASK;
244 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20);
248 early_param("mem", early_mem);
250 static int __init early_init_dt_scan_usablemem(unsigned long node,
251 const char *uname, int depth, void *data)
253 struct memblock_region *usablemem = data;
257 if (depth != 1 || strcmp(uname, "chosen") != 0)
260 reg = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
261 if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
264 usablemem->base = dt_mem_next_cell(dt_root_addr_cells, ®);
265 usablemem->size = dt_mem_next_cell(dt_root_size_cells, ®);
270 static void __init fdt_enforce_memory_region(void)
272 struct memblock_region reg = {
276 of_scan_flat_dt(early_init_dt_scan_usablemem, ®);
279 memblock_cap_memory_range(reg.base, reg.size);
282 void __init arm64_memblock_init(void)
284 const s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual);
286 /* Handle linux,usable-memory-range property */
287 fdt_enforce_memory_region();
289 /* Remove memory above our supported physical address size */
290 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);
293 * Select a suitable value for the base of physical memory.
295 memstart_addr = round_down(memblock_start_of_DRAM(),
296 ARM64_MEMSTART_ALIGN);
298 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size)
299 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n");
302 * Remove the memory that we will not be able to cover with the
303 * linear mapping. Take care not to clip the kernel which may be
306 memblock_remove(max_t(u64, memstart_addr + linear_region_size,
307 __pa_symbol(_end)), ULLONG_MAX);
308 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {
309 /* ensure that memstart_addr remains sufficiently aligned */
310 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size,
311 ARM64_MEMSTART_ALIGN);
312 memblock_remove(0, memstart_addr);
316 * If we are running with a 52-bit kernel VA config on a system that
317 * does not support it, we have to place the available physical
318 * memory in the 48-bit addressable part of the linear region, i.e.,
319 * we have to move it upward. Since memstart_addr represents the
320 * physical address of PAGE_OFFSET, we have to *subtract* from it.
322 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52))
323 memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52);
326 * Apply the memory limit if it was set. Since the kernel may be loaded
327 * high up in memory, add back the kernel region that must be accessible
328 * via the linear mapping.
330 if (memory_limit != PHYS_ADDR_MAX) {
331 memblock_mem_limit_remove_map(memory_limit);
332 memblock_add(__pa_symbol(_text), (u64)(_end - _text));
335 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
337 * Add back the memory we just removed if it results in the
338 * initrd to become inaccessible via the linear mapping.
339 * Otherwise, this is a no-op
341 u64 base = phys_initrd_start & PAGE_MASK;
342 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
345 * We can only add back the initrd memory if we don't end up
346 * with more memory than we can address via the linear mapping.
347 * It is up to the bootloader to position the kernel and the
348 * initrd reasonably close to each other (i.e., within 32 GB of
349 * each other) so that all granule/#levels combinations can
350 * always access both.
352 if (WARN(base < memblock_start_of_DRAM() ||
353 base + size > memblock_start_of_DRAM() +
355 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
356 phys_initrd_size = 0;
358 memblock_remove(base, size); /* clear MEMBLOCK_ flags */
359 memblock_add(base, size);
360 memblock_reserve(base, size);
364 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
365 extern u16 memstart_offset_seed;
366 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
367 int parange = cpuid_feature_extract_unsigned_field(
368 mmfr0, ID_AA64MMFR0_PARANGE_SHIFT);
369 s64 range = linear_region_size -
370 BIT(id_aa64mmfr0_parange_to_phys_shift(parange));
373 * If the size of the linear region exceeds, by a sufficient
374 * margin, the size of the region that the physical memory can
375 * span, randomize the linear region as well.
377 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) {
378 range /= ARM64_MEMSTART_ALIGN;
379 memstart_addr -= ARM64_MEMSTART_ALIGN *
380 ((range * memstart_offset_seed) >> 16);
385 * Register the kernel text, kernel data, initrd, and initial
386 * pagetables with memblock.
388 memblock_reserve(__pa_symbol(_stext), _end - _stext);
389 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
390 /* the generic initrd code expects virtual addresses */
391 initrd_start = __phys_to_virt(phys_initrd_start);
392 initrd_end = initrd_start + phys_initrd_size;
395 early_init_fdt_scan_reserved_mem();
397 if (IS_ENABLED(CONFIG_ZONE_DMA32))
398 arm64_dma32_phys_limit = max_zone_phys(32);
400 arm64_dma32_phys_limit = PHYS_MASK + 1;
402 reserve_elfcorehdr();
404 high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
406 dma_contiguous_reserve(arm64_dma32_phys_limit);
409 void __init bootmem_init(void)
411 unsigned long min, max;
413 min = PFN_UP(memblock_start_of_DRAM());
414 max = PFN_DOWN(memblock_end_of_DRAM());
416 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
418 max_pfn = max_low_pfn = max;
424 * must be done after arm64_numa_init() which calls numa_init() to
425 * initialize node_online_map that gets used in hugetlb_cma_reserve()
426 * while allocating required CMA size across online nodes.
428 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
429 arm64_hugetlb_cma_reserve();
432 dma_pernuma_cma_reserve();
435 * sparse_init() tries to allocate memory from memblock, so must be
436 * done after the fixed reservations
439 zone_sizes_init(min, max);
442 * request_standard_resources() depends on crashkernel's memory being
443 * reserved, so do it here.
445 reserve_crashkernel();
451 * mem_init() marks the free areas in the mem_map and tells us how much memory
452 * is free. This is done after various parts of the system have claimed their
453 * memory after the kernel image.
455 void __init mem_init(void)
457 if (swiotlb_force == SWIOTLB_FORCE ||
458 max_pfn > PFN_DOWN(arm64_dma_phys_limit ? : arm64_dma32_phys_limit))
461 swiotlb_force = SWIOTLB_NO_FORCE;
463 set_max_mapnr(max_pfn - PHYS_PFN_OFFSET);
465 /* this will put all unused low memory onto the freelists */
468 mem_init_print_info(NULL);
471 * Check boundaries twice: Some fundamental inconsistencies can be
472 * detected at build time already.
475 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64);
478 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
479 extern int sysctl_overcommit_memory;
481 * On a machine this small we won't get anywhere without
482 * overcommit, so turn it on by default.
484 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
488 void free_initmem(void)
490 free_reserved_area(lm_alias(__init_begin),
491 lm_alias(__init_end),
492 POISON_FREE_INITMEM, "unused kernel");
494 * Unmap the __init region but leave the VM area in place. This
495 * prevents the region from being reused for kernel modules, which
496 * is not supported by kallsyms.
498 unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
501 void dump_mem_limit(void)
503 if (memory_limit != PHYS_ADDR_MAX) {
504 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20);
506 pr_emerg("Memory Limit: none\n");