1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * PowerPC version
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 *
6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
7 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
8 * Copyright (C) 1996 Paul Mackerras
9 *
10 * Derived from "arch/i386/mm/init.c"
11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
12 *
13 * Dave Engebretsen <engebret@us.ibm.com>
14 * Rework for PPC64 port.
15 */
16
17 #undef DEBUG
18
19 #include <linux/signal.h>
20 #include <linux/sched.h>
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/string.h>
24 #include <linux/types.h>
25 #include <linux/mman.h>
26 #include <linux/mm.h>
27 #include <linux/swap.h>
28 #include <linux/stddef.h>
29 #include <linux/vmalloc.h>
30 #include <linux/init.h>
31 #include <linux/delay.h>
32 #include <linux/highmem.h>
33 #include <linux/idr.h>
34 #include <linux/nodemask.h>
35 #include <linux/module.h>
36 #include <linux/poison.h>
37 #include <linux/memblock.h>
38 #include <linux/hugetlb.h>
39 #include <linux/slab.h>
40 #include <linux/of_fdt.h>
41 #include <linux/libfdt.h>
42 #include <linux/memremap.h>
43 #include <linux/memory.h>
44
45 #include <asm/pgalloc.h>
46 #include <asm/page.h>
47 #include <asm/prom.h>
48 #include <asm/rtas.h>
49 #include <asm/io.h>
50 #include <asm/mmu_context.h>
51 #include <asm/mmu.h>
52 #include <linux/uaccess.h>
53 #include <asm/smp.h>
54 #include <asm/machdep.h>
55 #include <asm/tlb.h>
56 #include <asm/eeh.h>
57 #include <asm/processor.h>
58 #include <asm/mmzone.h>
59 #include <asm/cputable.h>
60 #include <asm/sections.h>
61 #include <asm/iommu.h>
62 #include <asm/vdso.h>
63 #include <asm/hugetlb.h>
64
65 #include <mm/mmu_decl.h>
66
67 #ifdef CONFIG_SPARSEMEM_VMEMMAP
68 /*
69 * Given an address within the vmemmap, determine the page that
70 * represents the start of the subsection it is within. Note that we have to
71 * do this by hand as the proffered address may not be correctly aligned.
72 * Subtraction of non-aligned pointers produces undefined results.
73 */
74 static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_addr)
75 {
76 unsigned long start_pfn;
77 unsigned long offset = vmemmap_addr - ((unsigned long)(vmemmap));
78
79 /* Return the pfn of the start of the section. */
80 start_pfn = (offset / sizeof(struct page)) & PAGE_SUBSECTION_MASK;
81 return pfn_to_page(start_pfn);
82 }
83
84 /*
85 * Since memory is added in sub-section chunks, before creating a new vmemmap
86 * mapping, the kernel should check whether there is an existing memmap mapping
87 * covering the new subsection added. This is needed because kernel can map
88 * vmemmap area using 16MB pages which will cover a memory range of 16G. Such
89 * a range covers multiple subsections (2M)
90 *
91 * If any subsection in the 16G range mapped by vmemmap is valid we consider the
92 * vmemmap populated (There is a page table entry already present). We can't do
93 * a page table lookup here because with the hash translation we don't keep
94 * vmemmap details in linux page table.
95 */
96 int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size)
97 {
98 struct page *start;
99 unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size;
100 start = vmemmap_subsection_start(vmemmap_addr);
101
102 for (; (unsigned long)start < vmemmap_end; start += PAGES_PER_SUBSECTION)
103 /*
104 * pfn valid check here is intended to really check
105 * whether we have any subsection already initialized
106 * in this range.
107 */
108 if (pfn_valid(page_to_pfn(start)))
109 return 1;
110
111 return 0;
112 }
113
114 /*
115 * vmemmap virtual address space management does not have a traditional page
116 * table to track which virtual struct pages are backed by physical mapping.
117 * The virtual to physical mappings are tracked in a simple linked list
118 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at
119 * all times where as the 'next' list maintains the available
120 * vmemmap_backing structures which have been deleted from the
121 * 'vmemmap_global' list during system runtime (memory hotplug remove
122 * operation). The freed 'vmemmap_backing' structures are reused later when
123 * new requests come in without allocating fresh memory. This pointer also
124 * tracks the allocated 'vmemmap_backing' structures as we allocate one
125 * full page memory at a time when we dont have any.
126 */
127 struct vmemmap_backing *vmemmap_list;
128 static struct vmemmap_backing *next;
129
130 /*
131 * The same pointer 'next' tracks individual chunks inside the allocated
132 * full page during the boot time and again tracks the freed nodes during
133 * runtime. It is racy but it does not happen as they are separated by the
134 * boot process. Will create problem if some how we have memory hotplug
135 * operation during boot !!
136 */
137 static int num_left;
138 static int num_freed;
139
140 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
141 {
142 struct vmemmap_backing *vmem_back;
143 /* get from freed entries first */
144 if (num_freed) {
145 num_freed--;
146 vmem_back = next;
147 next = next->list;
148
149 return vmem_back;
150 }
151
152 /* allocate a page when required and hand out chunks */
153 if (!num_left) {
154 next = vmemmap_alloc_block(PAGE_SIZE, node);
155 if (unlikely(!next)) {
156 WARN_ON(1);
157 return NULL;
158 }
159 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
160 }
161
162 num_left--;
163
164 return next++;
165 }
166
167 static __meminit int vmemmap_list_populate(unsigned long phys,
168 unsigned long start,
169 int node)
170 {
171 struct vmemmap_backing *vmem_back;
172
173 vmem_back = vmemmap_list_alloc(node);
174 if (unlikely(!vmem_back)) {
175 pr_debug("vmemap list allocation failed\n");
176 return -ENOMEM;
177 }
178
179 vmem_back->phys = phys;
180 vmem_back->virt_addr = start;
181 vmem_back->list = vmemmap_list;
182
183 vmemmap_list = vmem_back;
184 return 0;
185 }
186
187 bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
188 unsigned long page_size)
189 {
190 unsigned long nr_pfn = page_size / sizeof(struct page);
191 unsigned long start_pfn = page_to_pfn((struct page *)start);
192
193 if ((start_pfn + nr_pfn - 1) > altmap->end_pfn)
194 return true;
195
196 if (start_pfn < altmap->base_pfn)
197 return true;
198
199 return false;
200 }
201
202 static int __meminit __vmemmap_populate(unsigned long start, unsigned long end, int node,
203 struct vmem_altmap *altmap)
204 {
205 bool altmap_alloc;
206 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
207
208 /* Align to the page size of the linear mapping. */
209 start = ALIGN_DOWN(start, page_size);
210
211 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
212
213 for (; start < end; start += page_size) {
214 void *p = NULL;
215 int rc;
216
217 /*
218 * This vmemmap range is backing different subsections. If any
219 * of that subsection is marked valid, that means we already
220 * have initialized a page table covering this range and hence
221 * the vmemmap range is populated.
222 */
223 if (vmemmap_populated(start, page_size))
224 continue;
225
226 /*
227 * Allocate from the altmap first if we have one. This may
228 * fail due to alignment issues when using 16MB hugepages, so
229 * fall back to system memory if the altmap allocation fail.
230 */
231 if (altmap && !altmap_cross_boundary(altmap, start, page_size)) {
232 p = vmemmap_alloc_block_buf(page_size, node, altmap);
233 if (!p)
234 pr_debug("altmap block allocation failed, falling back to system memory");
235 else
236 altmap_alloc = true;
237 }
238 if (!p) {
239 p = vmemmap_alloc_block_buf(page_size, node, NULL);
240 altmap_alloc = false;
241 }
242 if (!p)
243 return -ENOMEM;
244
245 if (vmemmap_list_populate(__pa(p), start, node)) {
246 /*
247 * If we don't populate vmemap list, we don't have
248 * the ability to free the allocated vmemmap
249 * pages in section_deactivate. Hence free them
250 * here.
251 */
252 int nr_pfns = page_size >> PAGE_SHIFT;
253 unsigned long page_order = get_order(page_size);
254
255 if (altmap_alloc)
256 vmem_altmap_free(altmap, nr_pfns);
257 else
258 free_pages((unsigned long)p, page_order);
259 return -ENOMEM;
260 }
261
262 pr_debug(" * %016lx..%016lx allocated at %p\n",
263 start, start + page_size, p);
264
265 rc = vmemmap_create_mapping(start, page_size, __pa(p));
266 if (rc < 0) {
267 pr_warn("%s: Unable to create vmemmap mapping: %d\n",
268 __func__, rc);
269 return -EFAULT;
270 }
271 }
272
273 return 0;
274 }
275
276 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
277 struct vmem_altmap *altmap)
278 {
279
280 #ifdef CONFIG_PPC_BOOK3S_64
281 if (radix_enabled())
282 return radix__vmemmap_populate(start, end, node, altmap);
283 #endif
284
285 return __vmemmap_populate(start, end, node, altmap);
286 }
287
288 #ifdef CONFIG_MEMORY_HOTPLUG
289 static unsigned long vmemmap_list_free(unsigned long start)
290 {
291 struct vmemmap_backing *vmem_back, *vmem_back_prev;
292
293 vmem_back_prev = vmem_back = vmemmap_list;
294
295 /* look for it with prev pointer recorded */
296 for (; vmem_back; vmem_back = vmem_back->list) {
297 if (vmem_back->virt_addr == start)
298 break;
299 vmem_back_prev = vmem_back;
300 }
301
302 if (unlikely(!vmem_back))
303 return 0;
304
305 /* remove it from vmemmap_list */
306 if (vmem_back == vmemmap_list) /* remove head */
307 vmemmap_list = vmem_back->list;
308 else
309 vmem_back_prev->list = vmem_back->list;
310
311 /* next point to this freed entry */
312 vmem_back->list = next;
313 next = vmem_back;
314 num_freed++;
315
316 return vmem_back->phys;
317 }
318
319 static void __ref __vmemmap_free(unsigned long start, unsigned long end,
320 struct vmem_altmap *altmap)
321 {
322 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
323 unsigned long page_order = get_order(page_size);
324 unsigned long alt_start = ~0, alt_end = ~0;
325 unsigned long base_pfn;
326
327 start = ALIGN_DOWN(start, page_size);
328 if (altmap) {
329 alt_start = altmap->base_pfn;
330 alt_end = altmap->base_pfn + altmap->reserve + altmap->free;
331 }
332
333 pr_debug("vmemmap_free %lx...%lx\n", start, end);
334
335 for (; start < end; start += page_size) {
336 unsigned long nr_pages, addr;
337 struct page *page;
338
339 /*
340 * We have already marked the subsection we are trying to remove
341 * invalid. So if we want to remove the vmemmap range, we
342 * need to make sure there is no subsection marked valid
343 * in this range.
344 */
345 if (vmemmap_populated(start, page_size))
346 continue;
347
348 addr = vmemmap_list_free(start);
349 if (!addr)
350 continue;
351
352 page = pfn_to_page(addr >> PAGE_SHIFT);
353 nr_pages = 1 << page_order;
354 base_pfn = PHYS_PFN(addr);
355
356 if (base_pfn >= alt_start && base_pfn < alt_end) {
357 vmem_altmap_free(altmap, nr_pages);
358 } else if (PageReserved(page)) {
359 /* allocated from bootmem */
360 if (page_size < PAGE_SIZE) {
361 /*
362 * this shouldn't happen, but if it is
363 * the case, leave the memory there
364 */
365 WARN_ON_ONCE(1);
366 } else {
367 while (nr_pages--)
368 free_reserved_page(page++);
369 }
370 } else {
371 free_pages((unsigned long)(__va(addr)), page_order);
372 }
373
374 vmemmap_remove_mapping(start, page_size);
375 }
376 }
377
378 void __ref vmemmap_free(unsigned long start, unsigned long end,
379 struct vmem_altmap *altmap)
380 {
381 #ifdef CONFIG_PPC_BOOK3S_64
382 if (radix_enabled())
383 return radix__vmemmap_free(start, end, altmap);
384 #endif
385 return __vmemmap_free(start, end, altmap);
386 }
387
388 #endif
389 void register_page_bootmem_memmap(unsigned long section_nr,
390 struct page *start_page, unsigned long size)
391 {
392 }
393
394 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
395
396 #ifdef CONFIG_PPC_BOOK3S_64
397 unsigned int mmu_lpid_bits;
398 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
399 EXPORT_SYMBOL_GPL(mmu_lpid_bits);
400 #endif
401 unsigned int mmu_pid_bits;
402
403 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT);
404
405 static int __init parse_disable_radix(char *p)
406 {
407 bool val;
408
409 if (!p)
410 val = true;
411 else if (kstrtobool(p, &val))
412 return -EINVAL;
413
414 disable_radix = val;
415
416 return 0;
417 }
418 early_param("disable_radix", parse_disable_radix);
419
420 /*
421 * If we're running under a hypervisor, we need to check the contents of
422 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do
423 * radix. If not, we clear the radix feature bit so we fall back to hash.
424 */
425 static void __init early_check_vec5(void)
426 {
427 unsigned long root, chosen;
428 int size;
429 const u8 *vec5;
430 u8 mmu_supported;
431
432 root = of_get_flat_dt_root();
433 chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
434 if (chosen == -FDT_ERR_NOTFOUND) {
435 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
436 return;
437 }
438 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
439 if (!vec5) {
440 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
441 return;
442 }
443 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) {
444 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
445 return;
446 }
447
448 /* Check for supported configuration */
449 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] &
450 OV5_FEAT(OV5_MMU_SUPPORT);
451 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) {
452 /* Hypervisor only supports radix - check enabled && GTSE */
453 if (!early_radix_enabled()) {
454 pr_warn("WARNING: Ignoring cmdline option disable_radix\n");
455 }
456 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] &
457 OV5_FEAT(OV5_RADIX_GTSE))) {
458 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE;
459 } else
460 cur_cpu_spec->mmu_features |= MMU_FTR_GTSE;
461 /* Do radix anyway - the hypervisor said we had to */
462 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX;
463 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) {
464 /* Hypervisor only supports hash - disable radix */
465 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
466 cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE;
467 }
468 }
469
470 static int __init dt_scan_mmu_pid_width(unsigned long node,
471 const char *uname, int depth,
472 void *data)
473 {
474 int size = 0;
475 const __be32 *prop;
476 const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
477
478 /* We are scanning "cpu" nodes only */
479 if (type == NULL || strcmp(type, "cpu") != 0)
480 return 0;
481
482 /* Find MMU LPID, PID register size */
483 prop = of_get_flat_dt_prop(node, "ibm,mmu-lpid-bits", &size);
484 if (prop && size == 4)
485 mmu_lpid_bits = be32_to_cpup(prop);
486
487 prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
488 if (prop && size == 4)
489 mmu_pid_bits = be32_to_cpup(prop);
490
491 if (!mmu_pid_bits && !mmu_lpid_bits)
492 return 0;
493
494 return 1;
495 }
496
497 /*
498 * Outside hotplug the kernel uses this value to map the kernel direct map
499 * with radix. To be compatible with older kernels, let's keep this value
500 * as 16M which is also SECTION_SIZE with SPARSEMEM. We can ideally map
501 * things with 1GB size in the case where we don't support hotplug.
502 */
503 #ifndef CONFIG_MEMORY_HOTPLUG
504 #define DEFAULT_MEMORY_BLOCK_SIZE SZ_16M
505 #else
506 #define DEFAULT_MEMORY_BLOCK_SIZE MIN_MEMORY_BLOCK_SIZE
507 #endif
508
509 static void update_memory_block_size(unsigned long *block_size, unsigned long mem_size)
510 {
511 unsigned long min_memory_block_size = DEFAULT_MEMORY_BLOCK_SIZE;
512
513 for (; *block_size > min_memory_block_size; *block_size >>= 2) {
514 if ((mem_size & *block_size) == 0)
515 break;
516 }
517 }
518
519 static int __init probe_memory_block_size(unsigned long node, const char *uname, int
520 depth, void *data)
521 {
522 const char *type;
523 unsigned long *block_size = (unsigned long *)data;
524 const __be32 *reg, *endp;
525 int l;
526
527 if (depth != 1)
528 return 0;
529 /*
530 * If we have dynamic-reconfiguration-memory node, use the
531 * lmb value.
532 */
533 if (strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0) {
534
535 const __be32 *prop;
536
537 prop = of_get_flat_dt_prop(node, "ibm,lmb-size", &l);
538
539 if (!prop || l < dt_root_size_cells * sizeof(__be32))
540 /*
541 * Nothing in the device tree
542 */
543 *block_size = DEFAULT_MEMORY_BLOCK_SIZE;
544 else
545 *block_size = of_read_number(prop, dt_root_size_cells);
546 /*
547 * We have found the final value. Don't probe further.
548 */
549 return 1;
550 }
551 /*
552 * Find all the device tree nodes of memory type and make sure
553 * the area can be mapped using the memory block size value
554 * we end up using. We start with 1G value and keep reducing
555 * it such that we can map the entire area using memory_block_size.
556 * This will be used on powernv and older pseries that don't
557 * have ibm,lmb-size node.
558 * For ex: with P5 we can end up with
559 * memory@0 -> 128MB
560 * memory@128M -> 64M
561 * This will end up using 64MB memory block size value.
562 */
563 type = of_get_flat_dt_prop(node, "device_type", NULL);
564 if (type == NULL || strcmp(type, "memory") != 0)
565 return 0;
566
567 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
568 if (!reg)
569 reg = of_get_flat_dt_prop(node, "reg", &l);
570 if (!reg)
571 return 0;
572
573 endp = reg + (l / sizeof(__be32));
574 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
575 const char *compatible;
576 u64 size;
577
578 dt_mem_next_cell(dt_root_addr_cells, ®);
579 size = dt_mem_next_cell(dt_root_size_cells, ®);
580
581 if (size) {
582 update_memory_block_size(block_size, size);
583 continue;
584 }
585 /*
586 * ibm,coherent-device-memory with linux,usable-memory = 0
587 * Force 256MiB block size. Work around for GPUs on P9 PowerNV
588 * linux,usable-memory == 0 implies driver managed memory and
589 * we can't use large memory block size due to hotplug/unplug
590 * limitations.
591 */
592 compatible = of_get_flat_dt_prop(node, "compatible", NULL);
593 if (compatible && !strcmp(compatible, "ibm,coherent-device-memory")) {
594 if (*block_size > SZ_256M)
595 *block_size = SZ_256M;
596 /*
597 * We keep 256M as the upper limit with GPU present.
598 */
599 return 0;
600 }
601 }
602 /* continue looking for other memory device types */
603 return 0;
604 }
605
606 /*
607 * start with 1G memory block size. Early init will
608 * fix this with correct value.
609 */
610 unsigned long memory_block_size __ro_after_init = 1UL << 30;
611 static void __init early_init_memory_block_size(void)
612 {
613 /*
614 * We need to do memory_block_size probe early so that
615 * radix__early_init_mmu() can use this as limit for
616 * mapping page size.
617 */
618 of_scan_flat_dt(probe_memory_block_size, &memory_block_size);
619 }
620
621 void __init mmu_early_init_devtree(void)
622 {
623 bool hvmode = !!(mfmsr() & MSR_HV);
624
625 /* Disable radix mode based on kernel command line. */
626 if (disable_radix) {
627 if (IS_ENABLED(CONFIG_PPC_64S_HASH_MMU))
628 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
629 else
630 pr_warn("WARNING: Ignoring cmdline option disable_radix\n");
631 }
632
633 of_scan_flat_dt(dt_scan_mmu_pid_width, NULL);
634 if (hvmode && !mmu_lpid_bits) {
635 if (early_cpu_has_feature(CPU_FTR_ARCH_207S))
636 mmu_lpid_bits = 12; /* POWER8-10 */
637 else
638 mmu_lpid_bits = 10; /* POWER7 */
639 }
640 if (!mmu_pid_bits) {
641 if (early_cpu_has_feature(CPU_FTR_ARCH_300))
642 mmu_pid_bits = 20; /* POWER9-10 */
643 }
644
645 /*
646 * Check /chosen/ibm,architecture-vec-5 if running as a guest.
647 * When running bare-metal, we can use radix if we like
648 * even though the ibm,architecture-vec-5 property created by
649 * skiboot doesn't have the necessary bits set.
650 */
651 if (!hvmode)
652 early_check_vec5();
653
654 early_init_memory_block_size();
655
656 if (early_radix_enabled()) {
657 radix__early_init_devtree();
658
659 /*
660 * We have finalized the translation we are going to use by now.
661 * Radix mode is not limited by RMA / VRMA addressing.
662 * Hence don't limit memblock allocations.
663 */
664 ppc64_rma_size = ULONG_MAX;
665 memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
666 } else
667 hash__early_init_devtree();
668
669 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
670 hugetlbpage_init_defaultsize();
671
672 if (!(cur_cpu_spec->mmu_features & MMU_FTR_HPTE_TABLE) &&
673 !(cur_cpu_spec->mmu_features & MMU_FTR_TYPE_RADIX))
674 panic("kernel does not support any MMU type offered by platform");
675 }
676 #endif /* CONFIG_PPC_BOOK3S_64 */
677
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