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 /* Current arm64 boot protocol requires 2MB alignment */
68 #define CRASH_ALIGN SZ_2M
69
70 #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
71 #define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
72 #define CRASH_HIGH_SEARCH_BASE SZ_4G
73
74 #define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
75
76 /*
77 * To make optimal use of block mappings when laying out the linear
78 * mapping, round down the base of physical memory to a size that can
79 * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE
80 * (64k granule), or a multiple that can be mapped using contiguous bits
81 * in the page tables: 32 * PMD_SIZE (16k granule)
82 */
83 #if defined(CONFIG_ARM64_4K_PAGES)
84 #define ARM64_MEMSTART_SHIFT PUD_SHIFT
85 #elif defined(CONFIG_ARM64_16K_PAGES)
86 #define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT
87 #else
88 #define ARM64_MEMSTART_SHIFT PMD_SHIFT
89 #endif
90
91 /*
92 * sparsemem vmemmap imposes an additional requirement on the alignment of
93 * memstart_addr, due to the fact that the base of the vmemmap region
94 * has a direct correspondence, and needs to appear sufficiently aligned
95 * in the virtual address space.
96 */
97 #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
98 #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS)
99 #else
100 #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT)
101 #endif
102
reserve_crashkernel_low(unsigned long long low_size)103 static int __init reserve_crashkernel_low(unsigned long long low_size)
104 {
105 unsigned long long low_base;
106
107 low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
108 if (!low_base) {
109 pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
110 return -ENOMEM;
111 }
112
113 pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
114 low_base, low_base + low_size, low_size >> 20);
115
116 crashk_low_res.start = low_base;
117 crashk_low_res.end = low_base + low_size - 1;
118 insert_resource(&iomem_resource, &crashk_low_res);
119
120 return 0;
121 }
122
123 /*
124 * reserve_crashkernel() - reserves memory for crash kernel
125 *
126 * This function reserves memory area given in "crashkernel=" kernel command
127 * line parameter. The memory reserved is used by dump capture kernel when
128 * primary kernel is crashing.
129 */
reserve_crashkernel(void)130 static void __init reserve_crashkernel(void)
131 {
132 unsigned long long crash_low_size = 0, search_base = 0;
133 unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
134 unsigned long long crash_base, crash_size;
135 char *cmdline = boot_command_line;
136 bool fixed_base = false;
137 bool high = false;
138 int ret;
139
140 if (!IS_ENABLED(CONFIG_KEXEC_CORE))
141 return;
142
143 /* crashkernel=X[@offset] */
144 ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
145 &crash_size, &crash_base);
146 if (ret == -ENOENT) {
147 ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
148 if (ret || !crash_size)
149 return;
150
151 /*
152 * crashkernel=Y,low can be specified or not, but invalid value
153 * is not allowed.
154 */
155 ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
156 if (ret == -ENOENT)
157 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
158 else if (ret)
159 return;
160
161 search_base = CRASH_HIGH_SEARCH_BASE;
162 crash_max = CRASH_ADDR_HIGH_MAX;
163 high = true;
164 } else if (ret || !crash_size) {
165 /* The specified value is invalid */
166 return;
167 }
168
169 crash_size = PAGE_ALIGN(crash_size);
170
171 /* User specifies base address explicitly. */
172 if (crash_base) {
173 fixed_base = true;
174 search_base = crash_base;
175 crash_max = crash_base + crash_size;
176 }
177
178 retry:
179 crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
180 search_base, crash_max);
181 if (!crash_base) {
182 /*
183 * For crashkernel=size[KMG]@offset[KMG], print out failure
184 * message if can't reserve the specified region.
185 */
186 if (fixed_base) {
187 pr_warn("crashkernel reservation failed - memory is in use.\n");
188 return;
189 }
190
191 /*
192 * For crashkernel=size[KMG], if the first attempt was for
193 * low memory, fall back to high memory, the minimum required
194 * low memory will be reserved later.
195 */
196 if (!high && crash_max == CRASH_ADDR_LOW_MAX) {
197 crash_max = CRASH_ADDR_HIGH_MAX;
198 search_base = CRASH_ADDR_LOW_MAX;
199 crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
200 goto retry;
201 }
202
203 /*
204 * For crashkernel=size[KMG],high, if the first attempt was
205 * for high memory, fall back to low memory.
206 */
207 if (high && crash_max == CRASH_ADDR_HIGH_MAX) {
208 crash_max = CRASH_ADDR_LOW_MAX;
209 search_base = 0;
210 goto retry;
211 }
212 pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
213 crash_size);
214 return;
215 }
216
217 if ((crash_base >= CRASH_ADDR_LOW_MAX) && crash_low_size &&
218 reserve_crashkernel_low(crash_low_size)) {
219 memblock_phys_free(crash_base, crash_size);
220 return;
221 }
222
223 pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
224 crash_base, crash_base + crash_size, crash_size >> 20);
225
226 /*
227 * The crashkernel memory will be removed from the kernel linear
228 * map. Inform kmemleak so that it won't try to access it.
229 */
230 kmemleak_ignore_phys(crash_base);
231 if (crashk_low_res.end)
232 kmemleak_ignore_phys(crashk_low_res.start);
233
234 crashk_res.start = crash_base;
235 crashk_res.end = crash_base + crash_size - 1;
236 insert_resource(&iomem_resource, &crashk_res);
237 }
238
239 /*
240 * Return the maximum physical address for a zone accessible by the given bits
241 * limit. If DRAM starts above 32-bit, expand the zone to the maximum
242 * available memory, otherwise cap it at 32-bit.
243 */
max_zone_phys(unsigned int zone_bits)244 static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
245 {
246 phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits);
247 phys_addr_t phys_start = memblock_start_of_DRAM();
248
249 if (phys_start > U32_MAX)
250 zone_mask = PHYS_ADDR_MAX;
251 else if (phys_start > zone_mask)
252 zone_mask = U32_MAX;
253
254 return min(zone_mask, memblock_end_of_DRAM() - 1) + 1;
255 }
256
zone_sizes_init(void)257 static void __init zone_sizes_init(void)
258 {
259 unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
260 unsigned int __maybe_unused acpi_zone_dma_bits;
261 unsigned int __maybe_unused dt_zone_dma_bits;
262 phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32);
263
264 #ifdef CONFIG_ZONE_DMA
265 acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address());
266 dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
267 zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits);
268 arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
269 max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
270 #endif
271 #ifdef CONFIG_ZONE_DMA32
272 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit);
273 if (!arm64_dma_phys_limit)
274 arm64_dma_phys_limit = dma32_phys_limit;
275 #endif
276 if (!arm64_dma_phys_limit)
277 arm64_dma_phys_limit = PHYS_MASK + 1;
278 max_zone_pfns[ZONE_NORMAL] = max_pfn;
279
280 free_area_init(max_zone_pfns);
281 }
282
pfn_is_map_memory(unsigned long pfn)283 int pfn_is_map_memory(unsigned long pfn)
284 {
285 phys_addr_t addr = PFN_PHYS(pfn);
286
287 /* avoid false positives for bogus PFNs, see comment in pfn_valid() */
288 if (PHYS_PFN(addr) != pfn)
289 return 0;
290
291 return memblock_is_map_memory(addr);
292 }
293 EXPORT_SYMBOL(pfn_is_map_memory);
294
295 static phys_addr_t memory_limit __ro_after_init = PHYS_ADDR_MAX;
296
297 /*
298 * Limit the memory size that was specified via FDT.
299 */
early_mem(char * p)300 static int __init early_mem(char *p)
301 {
302 if (!p)
303 return 1;
304
305 memory_limit = memparse(p, &p) & PAGE_MASK;
306 pr_notice("Memory limited to %lldMB\n", memory_limit >> 20);
307
308 return 0;
309 }
310 early_param("mem", early_mem);
311
arm64_memblock_init(void)312 void __init arm64_memblock_init(void)
313 {
314 s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual);
315
316 /*
317 * Corner case: 52-bit VA capable systems running KVM in nVHE mode may
318 * be limited in their ability to support a linear map that exceeds 51
319 * bits of VA space, depending on the placement of the ID map. Given
320 * that the placement of the ID map may be randomized, let's simply
321 * limit the kernel's linear map to 51 bits as well if we detect this
322 * configuration.
323 */
324 if (IS_ENABLED(CONFIG_KVM) && vabits_actual == 52 &&
325 is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
326 pr_info("Capping linear region to 51 bits for KVM in nVHE mode on LVA capable hardware.\n");
327 linear_region_size = min_t(u64, linear_region_size, BIT(51));
328 }
329
330 /* Remove memory above our supported physical address size */
331 memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);
332
333 /*
334 * Select a suitable value for the base of physical memory.
335 */
336 memstart_addr = round_down(memblock_start_of_DRAM(),
337 ARM64_MEMSTART_ALIGN);
338
339 if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size)
340 pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n");
341
342 /*
343 * Remove the memory that we will not be able to cover with the
344 * linear mapping. Take care not to clip the kernel which may be
345 * high in memory.
346 */
347 memblock_remove(max_t(u64, memstart_addr + linear_region_size,
348 __pa_symbol(_end)), ULLONG_MAX);
349 if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) {
350 /* ensure that memstart_addr remains sufficiently aligned */
351 memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size,
352 ARM64_MEMSTART_ALIGN);
353 memblock_remove(0, memstart_addr);
354 }
355
356 /*
357 * If we are running with a 52-bit kernel VA config on a system that
358 * does not support it, we have to place the available physical
359 * memory in the 48-bit addressable part of the linear region, i.e.,
360 * we have to move it upward. Since memstart_addr represents the
361 * physical address of PAGE_OFFSET, we have to *subtract* from it.
362 */
363 if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52))
364 memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52);
365
366 /*
367 * Apply the memory limit if it was set. Since the kernel may be loaded
368 * high up in memory, add back the kernel region that must be accessible
369 * via the linear mapping.
370 */
371 if (memory_limit != PHYS_ADDR_MAX) {
372 memblock_mem_limit_remove_map(memory_limit);
373 memblock_add(__pa_symbol(_text), (u64)(_end - _text));
374 }
375
376 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
377 /*
378 * Add back the memory we just removed if it results in the
379 * initrd to become inaccessible via the linear mapping.
380 * Otherwise, this is a no-op
381 */
382 u64 base = phys_initrd_start & PAGE_MASK;
383 u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
384
385 /*
386 * We can only add back the initrd memory if we don't end up
387 * with more memory than we can address via the linear mapping.
388 * It is up to the bootloader to position the kernel and the
389 * initrd reasonably close to each other (i.e., within 32 GB of
390 * each other) so that all granule/#levels combinations can
391 * always access both.
392 */
393 if (WARN(base < memblock_start_of_DRAM() ||
394 base + size > memblock_start_of_DRAM() +
395 linear_region_size,
396 "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
397 phys_initrd_size = 0;
398 } else {
399 memblock_add(base, size);
400 memblock_clear_nomap(base, size);
401 memblock_reserve(base, size);
402 }
403 }
404
405 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
406 extern u16 memstart_offset_seed;
407 u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
408 int parange = cpuid_feature_extract_unsigned_field(
409 mmfr0, ID_AA64MMFR0_EL1_PARANGE_SHIFT);
410 s64 range = linear_region_size -
411 BIT(id_aa64mmfr0_parange_to_phys_shift(parange));
412
413 /*
414 * If the size of the linear region exceeds, by a sufficient
415 * margin, the size of the region that the physical memory can
416 * span, randomize the linear region as well.
417 */
418 if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) {
419 range /= ARM64_MEMSTART_ALIGN;
420 memstart_addr -= ARM64_MEMSTART_ALIGN *
421 ((range * memstart_offset_seed) >> 16);
422 }
423 }
424
425 /*
426 * Register the kernel text, kernel data, initrd, and initial
427 * pagetables with memblock.
428 */
429 memblock_reserve(__pa_symbol(_stext), _end - _stext);
430 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
431 /* the generic initrd code expects virtual addresses */
432 initrd_start = __phys_to_virt(phys_initrd_start);
433 initrd_end = initrd_start + phys_initrd_size;
434 }
435
436 early_init_fdt_scan_reserved_mem();
437
438 high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
439 }
440
bootmem_init(void)441 void __init bootmem_init(void)
442 {
443 unsigned long min, max;
444
445 min = PFN_UP(memblock_start_of_DRAM());
446 max = PFN_DOWN(memblock_end_of_DRAM());
447
448 early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
449
450 max_pfn = max_low_pfn = max;
451 min_low_pfn = min;
452
453 arch_numa_init();
454
455 /*
456 * must be done after arch_numa_init() which calls numa_init() to
457 * initialize node_online_map that gets used in hugetlb_cma_reserve()
458 * while allocating required CMA size across online nodes.
459 */
460 #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
461 arm64_hugetlb_cma_reserve();
462 #endif
463
464 kvm_hyp_reserve();
465
466 /*
467 * sparse_init() tries to allocate memory from memblock, so must be
468 * done after the fixed reservations
469 */
470 sparse_init();
471 zone_sizes_init();
472
473 /*
474 * Reserve the CMA area after arm64_dma_phys_limit was initialised.
475 */
476 dma_contiguous_reserve(arm64_dma_phys_limit);
477
478 /*
479 * request_standard_resources() depends on crashkernel's memory being
480 * reserved, so do it here.
481 */
482 reserve_crashkernel();
483
484 memblock_dump_all();
485 }
486
487 /*
488 * mem_init() marks the free areas in the mem_map and tells us how much memory
489 * is free. This is done after various parts of the system have claimed their
490 * memory after the kernel image.
491 */
mem_init(void)492 void __init mem_init(void)
493 {
494 bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit);
495
496 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC))
497 swiotlb = true;
498
499 swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
500
501 /* this will put all unused low memory onto the freelists */
502 memblock_free_all();
503
504 /*
505 * Check boundaries twice: Some fundamental inconsistencies can be
506 * detected at build time already.
507 */
508 #ifdef CONFIG_COMPAT
509 BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64);
510 #endif
511
512 /*
513 * Selected page table levels should match when derived from
514 * scratch using the virtual address range and page size.
515 */
516 BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) !=
517 CONFIG_PGTABLE_LEVELS);
518
519 if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
520 extern int sysctl_overcommit_memory;
521 /*
522 * On a machine this small we won't get anywhere without
523 * overcommit, so turn it on by default.
524 */
525 sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
526 }
527 }
528
free_initmem(void)529 void free_initmem(void)
530 {
531 free_reserved_area(lm_alias(__init_begin),
532 lm_alias(__init_end),
533 POISON_FREE_INITMEM, "unused kernel");
534 /*
535 * Unmap the __init region but leave the VM area in place. This
536 * prevents the region from being reused for kernel modules, which
537 * is not supported by kallsyms.
538 */
539 vunmap_range((u64)__init_begin, (u64)__init_end);
540 }
541
dump_mem_limit(void)542 void dump_mem_limit(void)
543 {
544 if (memory_limit != PHYS_ADDR_MAX) {
545 pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20);
546 } else {
547 pr_emerg("Memory Limit: none\n");
548 }
549 }
550