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/kvm_host.h>
39 #include <asm/memory.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
43 #include <linux/sizes.h>
45 #include <asm/alternative.h>
46 #include <asm/xen/swiotlb-xen.h>
49 * We need to be able to catch inadvertent references to memstart_addr
50 * that occur (potentially in generic code) before arm64_memblock_init()
51 * executes, which assigns it its actual value. So use a default value
52 * that cannot be mistaken for a real physical address.
54 s64 memstart_addr __ro_after_init = -1;
55 EXPORT_SYMBOL(memstart_addr);
58 * If the corresponding config options are enabled, we create both ZONE_DMA
59 * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory
60 * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4).
61 * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory,
62 * otherwise it is empty.
64 phys_addr_t arm64_dma_phys_limit __ro_after_init;
66 #ifdef CONFIG_KEXEC_CORE
68 * reserve_crashkernel() - reserves memory for crash kernel
70 * This function reserves memory area given in "crashkernel=" kernel command
71 * line parameter. The memory reserved is used by dump capture kernel when
72 * primary kernel is crashing.
74 static void __init reserve_crashkernel(void)
76 unsigned long long crash_base, crash_size;
79 ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
80 &crash_size, &crash_base);
81 /* no crashkernel= or invalid value specified */
82 if (ret || !crash_size)
85 crash_size = PAGE_ALIGN(crash_size);
87 if (crash_base == 0) {
88 /* Current arm64 boot protocol requires 2MB alignment */
89 crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
91 if (crash_base == 0) {
92 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
97 /* User specifies base address explicitly. */
98 if (!memblock_is_region_memory(crash_base, crash_size)) {
99 pr_warn("cannot reserve crashkernel: region is not memory\n");
103 if (memblock_is_region_reserved(crash_base, crash_size)) {
104 pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
108 if (!IS_ALIGNED(crash_base, SZ_2M)) {
109 pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
113 memblock_reserve(crash_base, crash_size);
115 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
116 crash_base, crash_base + crash_size, crash_size >> 20);
118 crashk_res.start = crash_base;
119 crashk_res.end = crash_base + crash_size - 1;
122 static void __init reserve_crashkernel(void)
125 #endif /* CONFIG_KEXEC_CORE */
128 * Return the maximum physical address for a zone accessible by the given bits
129 * limit. If DRAM starts above 32-bit, expand the zone to the maximum
130 * available memory, otherwise cap it at 32-bit.
132 static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
134 phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits);
135 phys_addr_t phys_start = memblock_start_of_DRAM();
137 if (phys_start > U32_MAX)
138 zone_mask = PHYS_ADDR_MAX;
139 else if (phys_start > zone_mask)
142 return min(zone_mask, memblock_end_of_DRAM() - 1) + 1;
145 static void __init zone_sizes_init(unsigned long min, unsigned long max)
147 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
148 unsigned int __maybe_unused acpi_zone_dma_bits;
149 unsigned int __maybe_unused dt_zone_dma_bits;
150 phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32);
152 #ifdef CONFIG_ZONE_DMA
153 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address());
154 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
155 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits);
156 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
157 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
159 #ifdef CONFIG_ZONE_DMA32
160 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit);
161 if (!arm64_dma_phys_limit)
162 arm64_dma_phys_limit = dma32_phys_limit;
164 if (!arm64_dma_phys_limit)
165 arm64_dma_phys_limit = PHYS_MASK + 1;
166 max_zone_pfns[ZONE_NORMAL] = max;
168 free_area_init(max_zone_pfns);
171 int pfn_valid(unsigned long pfn)
173 phys_addr_t addr = PFN_PHYS(pfn);
174 struct mem_section *ms;
177 * Ensure the upper PAGE_SHIFT bits are clear in the
178 * pfn. Else it might lead to false positives when
179 * some of the upper bits are set, but the lower bits
182 if (PHYS_PFN(addr) != pfn)
185 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
188 ms = __pfn_to_section(pfn);
189 if (!valid_section(ms))
193 * ZONE_DEVICE memory does not have the memblock entries.
194 * memblock_is_map_memory() check for ZONE_DEVICE based
195 * addresses will always fail. Even the normal hotplugged
196 * memory will never have MEMBLOCK_NOMAP flag set in their
197 * memblock entries. Skip memblock search for all non early
198 * memory sections covering all of hotplug memory including
199 * both normal and ZONE_DEVICE based.
201 if (!early_section(ms))
202 return pfn_section_valid(ms, pfn);
204 return memblock_is_memory(addr);
206 EXPORT_SYMBOL(pfn_valid);
208 int pfn_is_map_memory(unsigned long pfn)
210 phys_addr_t addr = PFN_PHYS(pfn);
212 /* avoid false positives for bogus PFNs, see comment in pfn_valid() */
213 if (PHYS_PFN(addr) != pfn)
216 return memblock_is_map_memory(addr);
218 EXPORT_SYMBOL(pfn_is_map_memory);
220 static phys_addr_t memory_limit = PHYS_ADDR_MAX;
223 * Limit the memory size that was specified via FDT.
225 static int __init early_mem(char *p)
230 memory_limit = memparse(p, &p) & PAGE_MASK;
231 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20);
235 early_param("mem", early_mem);
237 void __init arm64_memblock_init(void)
239 const s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual);
241 /* Remove memory above our supported physical address size */
242 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);
245 * Select a suitable value for the base of physical memory.
247 memstart_addr = round_down(memblock_start_of_DRAM(),
248 ARM64_MEMSTART_ALIGN);
250 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size)
251 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n");
254 * Remove the memory that we will not be able to cover with the
255 * linear mapping. Take care not to clip the kernel which may be
258 memblock_remove(max_t(u64, memstart_addr + linear_region_size,
259 __pa_symbol(_end)), ULLONG_MAX);
260 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {
261 /* ensure that memstart_addr remains sufficiently aligned */
262 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size,
263 ARM64_MEMSTART_ALIGN);
264 memblock_remove(0, memstart_addr);
268 * If we are running with a 52-bit kernel VA config on a system that
269 * does not support it, we have to place the available physical
270 * memory in the 48-bit addressable part of the linear region, i.e.,
271 * we have to move it upward. Since memstart_addr represents the
272 * physical address of PAGE_OFFSET, we have to *subtract* from it.
274 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52))
275 memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52);
278 * Apply the memory limit if it was set. Since the kernel may be loaded
279 * high up in memory, add back the kernel region that must be accessible
280 * via the linear mapping.
282 if (memory_limit != PHYS_ADDR_MAX) {
283 memblock_mem_limit_remove_map(memory_limit);
284 memblock_add(__pa_symbol(_text), (u64)(_end - _text));
287 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
289 * Add back the memory we just removed if it results in the
290 * initrd to become inaccessible via the linear mapping.
291 * Otherwise, this is a no-op
293 u64 base = phys_initrd_start & PAGE_MASK;
294 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
297 * We can only add back the initrd memory if we don't end up
298 * with more memory than we can address via the linear mapping.
299 * It is up to the bootloader to position the kernel and the
300 * initrd reasonably close to each other (i.e., within 32 GB of
301 * each other) so that all granule/#levels combinations can
302 * always access both.
304 if (WARN(base < memblock_start_of_DRAM() ||
305 base + size > memblock_start_of_DRAM() +
307 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
308 phys_initrd_size = 0;
310 memblock_remove(base, size); /* clear MEMBLOCK_ flags */
311 memblock_add(base, size);
312 memblock_reserve(base, size);
316 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
317 extern u16 memstart_offset_seed;
318 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
319 int parange = cpuid_feature_extract_unsigned_field(
320 mmfr0, ID_AA64MMFR0_PARANGE_SHIFT);
321 s64 range = linear_region_size -
322 BIT(id_aa64mmfr0_parange_to_phys_shift(parange));
325 * If the size of the linear region exceeds, by a sufficient
326 * margin, the size of the region that the physical memory can
327 * span, randomize the linear region as well.
329 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) {
330 range /= ARM64_MEMSTART_ALIGN;
331 memstart_addr -= ARM64_MEMSTART_ALIGN *
332 ((range * memstart_offset_seed) >> 16);
337 * Register the kernel text, kernel data, initrd, and initial
338 * pagetables with memblock.
340 memblock_reserve(__pa_symbol(_stext), _end - _stext);
341 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
342 /* the generic initrd code expects virtual addresses */
343 initrd_start = __phys_to_virt(phys_initrd_start);
344 initrd_end = initrd_start + phys_initrd_size;
347 early_init_fdt_scan_reserved_mem();
349 high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
352 void __init bootmem_init(void)
354 unsigned long min, max;
356 min = PFN_UP(memblock_start_of_DRAM());
357 max = PFN_DOWN(memblock_end_of_DRAM());
359 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
361 max_pfn = max_low_pfn = max;
367 * must be done after arch_numa_init() which calls numa_init() to
368 * initialize node_online_map that gets used in hugetlb_cma_reserve()
369 * while allocating required CMA size across online nodes.
371 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
372 arm64_hugetlb_cma_reserve();
375 dma_pernuma_cma_reserve();
380 * sparse_init() tries to allocate memory from memblock, so must be
381 * done after the fixed reservations
384 zone_sizes_init(min, max);
387 * Reserve the CMA area after arm64_dma_phys_limit was initialised.
389 dma_contiguous_reserve(arm64_dma_phys_limit);
392 * request_standard_resources() depends on crashkernel's memory being
393 * reserved, so do it here.
395 reserve_crashkernel();
401 * mem_init() marks the free areas in the mem_map and tells us how much memory
402 * is free. This is done after various parts of the system have claimed their
403 * memory after the kernel image.
405 void __init mem_init(void)
407 if (swiotlb_force == SWIOTLB_FORCE ||
408 max_pfn > PFN_DOWN(arm64_dma_phys_limit))
410 else if (!xen_swiotlb_detect())
411 swiotlb_force = SWIOTLB_NO_FORCE;
413 set_max_mapnr(max_pfn - PHYS_PFN_OFFSET);
415 /* this will put all unused low memory onto the freelists */
419 * Check boundaries twice: Some fundamental inconsistencies can be
420 * detected at build time already.
423 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64);
427 * Selected page table levels should match when derived from
428 * scratch using the virtual address range and page size.
430 BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) !=
431 CONFIG_PGTABLE_LEVELS);
433 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
434 extern int sysctl_overcommit_memory;
436 * On a machine this small we won't get anywhere without
437 * overcommit, so turn it on by default.
439 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
443 void free_initmem(void)
445 free_reserved_area(lm_alias(__init_begin),
446 lm_alias(__init_end),
447 POISON_FREE_INITMEM, "unused kernel");
449 * Unmap the __init region but leave the VM area in place. This
450 * prevents the region from being reused for kernel modules, which
451 * is not supported by kallsyms.
453 vunmap_range((u64)__init_begin, (u64)__init_end);
456 void dump_mem_limit(void)
458 if (memory_limit != PHYS_ADDR_MAX) {
459 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20);
461 pr_emerg("Memory Limit: none\n");