xref: /openbmc/linux/arch/powerpc/mm/init_64.c (revision e8f6f3b4)
1 /*
2  *  PowerPC version
3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4  *
5  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
6  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
7  *    Copyright (C) 1996 Paul Mackerras
8  *
9  *  Derived from "arch/i386/mm/init.c"
10  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
11  *
12  *  Dave Engebretsen <engebret@us.ibm.com>
13  *      Rework for PPC64 port.
14  *
15  *  This program is free software; you can redistribute it and/or
16  *  modify it under the terms of the GNU General Public License
17  *  as published by the Free Software Foundation; either version
18  *  2 of the License, or (at your option) any later version.
19  *
20  */
21 
22 #undef DEBUG
23 
24 #include <linux/signal.h>
25 #include <linux/sched.h>
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/string.h>
29 #include <linux/types.h>
30 #include <linux/mman.h>
31 #include <linux/mm.h>
32 #include <linux/swap.h>
33 #include <linux/stddef.h>
34 #include <linux/vmalloc.h>
35 #include <linux/init.h>
36 #include <linux/delay.h>
37 #include <linux/highmem.h>
38 #include <linux/idr.h>
39 #include <linux/nodemask.h>
40 #include <linux/module.h>
41 #include <linux/poison.h>
42 #include <linux/memblock.h>
43 #include <linux/hugetlb.h>
44 #include <linux/slab.h>
45 
46 #include <asm/pgalloc.h>
47 #include <asm/page.h>
48 #include <asm/prom.h>
49 #include <asm/rtas.h>
50 #include <asm/io.h>
51 #include <asm/mmu_context.h>
52 #include <asm/pgtable.h>
53 #include <asm/mmu.h>
54 #include <asm/uaccess.h>
55 #include <asm/smp.h>
56 #include <asm/machdep.h>
57 #include <asm/tlb.h>
58 #include <asm/eeh.h>
59 #include <asm/processor.h>
60 #include <asm/mmzone.h>
61 #include <asm/cputable.h>
62 #include <asm/sections.h>
63 #include <asm/iommu.h>
64 #include <asm/vdso.h>
65 
66 #include "mmu_decl.h"
67 
68 #ifdef CONFIG_PPC_STD_MMU_64
69 #if PGTABLE_RANGE > USER_VSID_RANGE
70 #warning Limited user VSID range means pagetable space is wasted
71 #endif
72 
73 #if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
74 #warning TASK_SIZE is smaller than it needs to be.
75 #endif
76 #endif /* CONFIG_PPC_STD_MMU_64 */
77 
78 phys_addr_t memstart_addr = ~0;
79 EXPORT_SYMBOL_GPL(memstart_addr);
80 phys_addr_t kernstart_addr;
81 EXPORT_SYMBOL_GPL(kernstart_addr);
82 
83 static void pgd_ctor(void *addr)
84 {
85 	memset(addr, 0, PGD_TABLE_SIZE);
86 }
87 
88 static void pmd_ctor(void *addr)
89 {
90 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
91 	memset(addr, 0, PMD_TABLE_SIZE * 2);
92 #else
93 	memset(addr, 0, PMD_TABLE_SIZE);
94 #endif
95 }
96 
97 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
98 
99 /*
100  * Create a kmem_cache() for pagetables.  This is not used for PTE
101  * pages - they're linked to struct page, come from the normal free
102  * pages pool and have a different entry size (see real_pte_t) to
103  * everything else.  Caches created by this function are used for all
104  * the higher level pagetables, and for hugepage pagetables.
105  */
106 void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
107 {
108 	char *name;
109 	unsigned long table_size = sizeof(void *) << shift;
110 	unsigned long align = table_size;
111 
112 	/* When batching pgtable pointers for RCU freeing, we store
113 	 * the index size in the low bits.  Table alignment must be
114 	 * big enough to fit it.
115 	 *
116 	 * Likewise, hugeapge pagetable pointers contain a (different)
117 	 * shift value in the low bits.  All tables must be aligned so
118 	 * as to leave enough 0 bits in the address to contain it. */
119 	unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
120 				     HUGEPD_SHIFT_MASK + 1);
121 	struct kmem_cache *new;
122 
123 	/* It would be nice if this was a BUILD_BUG_ON(), but at the
124 	 * moment, gcc doesn't seem to recognize is_power_of_2 as a
125 	 * constant expression, so so much for that. */
126 	BUG_ON(!is_power_of_2(minalign));
127 	BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
128 
129 	if (PGT_CACHE(shift))
130 		return; /* Already have a cache of this size */
131 
132 	align = max_t(unsigned long, align, minalign);
133 	name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
134 	new = kmem_cache_create(name, table_size, align, 0, ctor);
135 	pgtable_cache[shift - 1] = new;
136 	pr_debug("Allocated pgtable cache for order %d\n", shift);
137 }
138 
139 
140 void pgtable_cache_init(void)
141 {
142 	pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
143 	pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
144 	if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_CACHE_INDEX))
145 		panic("Couldn't allocate pgtable caches");
146 	/* In all current configs, when the PUD index exists it's the
147 	 * same size as either the pgd or pmd index.  Verify that the
148 	 * initialization above has also created a PUD cache.  This
149 	 * will need re-examiniation if we add new possibilities for
150 	 * the pagetable layout. */
151 	BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
152 }
153 
154 #ifdef CONFIG_SPARSEMEM_VMEMMAP
155 /*
156  * Given an address within the vmemmap, determine the pfn of the page that
157  * represents the start of the section it is within.  Note that we have to
158  * do this by hand as the proffered address may not be correctly aligned.
159  * Subtraction of non-aligned pointers produces undefined results.
160  */
161 static unsigned long __meminit vmemmap_section_start(unsigned long page)
162 {
163 	unsigned long offset = page - ((unsigned long)(vmemmap));
164 
165 	/* Return the pfn of the start of the section. */
166 	return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
167 }
168 
169 /*
170  * Check if this vmemmap page is already initialised.  If any section
171  * which overlaps this vmemmap page is initialised then this page is
172  * initialised already.
173  */
174 static int __meminit vmemmap_populated(unsigned long start, int page_size)
175 {
176 	unsigned long end = start + page_size;
177 	start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
178 
179 	for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
180 		if (pfn_valid(page_to_pfn((struct page *)start)))
181 			return 1;
182 
183 	return 0;
184 }
185 
186 /* On hash-based CPUs, the vmemmap is bolted in the hash table.
187  *
188  * On Book3E CPUs, the vmemmap is currently mapped in the top half of
189  * the vmalloc space using normal page tables, though the size of
190  * pages encoded in the PTEs can be different
191  */
192 
193 #ifdef CONFIG_PPC_BOOK3E
194 static void __meminit vmemmap_create_mapping(unsigned long start,
195 					     unsigned long page_size,
196 					     unsigned long phys)
197 {
198 	/* Create a PTE encoding without page size */
199 	unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
200 		_PAGE_KERNEL_RW;
201 
202 	/* PTEs only contain page size encodings up to 32M */
203 	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
204 
205 	/* Encode the size in the PTE */
206 	flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
207 
208 	/* For each PTE for that area, map things. Note that we don't
209 	 * increment phys because all PTEs are of the large size and
210 	 * thus must have the low bits clear
211 	 */
212 	for (i = 0; i < page_size; i += PAGE_SIZE)
213 		BUG_ON(map_kernel_page(start + i, phys, flags));
214 }
215 
216 #ifdef CONFIG_MEMORY_HOTPLUG
217 static void vmemmap_remove_mapping(unsigned long start,
218 				   unsigned long page_size)
219 {
220 }
221 #endif
222 #else /* CONFIG_PPC_BOOK3E */
223 static void __meminit vmemmap_create_mapping(unsigned long start,
224 					     unsigned long page_size,
225 					     unsigned long phys)
226 {
227 	int  mapped = htab_bolt_mapping(start, start + page_size, phys,
228 					pgprot_val(PAGE_KERNEL),
229 					mmu_vmemmap_psize,
230 					mmu_kernel_ssize);
231 	BUG_ON(mapped < 0);
232 }
233 
234 #ifdef CONFIG_MEMORY_HOTPLUG
235 static void vmemmap_remove_mapping(unsigned long start,
236 				   unsigned long page_size)
237 {
238 	int mapped = htab_remove_mapping(start, start + page_size,
239 					 mmu_vmemmap_psize,
240 					 mmu_kernel_ssize);
241 	BUG_ON(mapped < 0);
242 }
243 #endif
244 
245 #endif /* CONFIG_PPC_BOOK3E */
246 
247 struct vmemmap_backing *vmemmap_list;
248 static struct vmemmap_backing *next;
249 static int num_left;
250 static int num_freed;
251 
252 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
253 {
254 	struct vmemmap_backing *vmem_back;
255 	/* get from freed entries first */
256 	if (num_freed) {
257 		num_freed--;
258 		vmem_back = next;
259 		next = next->list;
260 
261 		return vmem_back;
262 	}
263 
264 	/* allocate a page when required and hand out chunks */
265 	if (!num_left) {
266 		next = vmemmap_alloc_block(PAGE_SIZE, node);
267 		if (unlikely(!next)) {
268 			WARN_ON(1);
269 			return NULL;
270 		}
271 		num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
272 	}
273 
274 	num_left--;
275 
276 	return next++;
277 }
278 
279 static __meminit void vmemmap_list_populate(unsigned long phys,
280 					    unsigned long start,
281 					    int node)
282 {
283 	struct vmemmap_backing *vmem_back;
284 
285 	vmem_back = vmemmap_list_alloc(node);
286 	if (unlikely(!vmem_back)) {
287 		WARN_ON(1);
288 		return;
289 	}
290 
291 	vmem_back->phys = phys;
292 	vmem_back->virt_addr = start;
293 	vmem_back->list = vmemmap_list;
294 
295 	vmemmap_list = vmem_back;
296 }
297 
298 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
299 {
300 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
301 
302 	/* Align to the page size of the linear mapping. */
303 	start = _ALIGN_DOWN(start, page_size);
304 
305 	pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
306 
307 	for (; start < end; start += page_size) {
308 		void *p;
309 
310 		if (vmemmap_populated(start, page_size))
311 			continue;
312 
313 		p = vmemmap_alloc_block(page_size, node);
314 		if (!p)
315 			return -ENOMEM;
316 
317 		vmemmap_list_populate(__pa(p), start, node);
318 
319 		pr_debug("      * %016lx..%016lx allocated at %p\n",
320 			 start, start + page_size, p);
321 
322 		vmemmap_create_mapping(start, page_size, __pa(p));
323 	}
324 
325 	return 0;
326 }
327 
328 #ifdef CONFIG_MEMORY_HOTPLUG
329 static unsigned long vmemmap_list_free(unsigned long start)
330 {
331 	struct vmemmap_backing *vmem_back, *vmem_back_prev;
332 
333 	vmem_back_prev = vmem_back = vmemmap_list;
334 
335 	/* look for it with prev pointer recorded */
336 	for (; vmem_back; vmem_back = vmem_back->list) {
337 		if (vmem_back->virt_addr == start)
338 			break;
339 		vmem_back_prev = vmem_back;
340 	}
341 
342 	if (unlikely(!vmem_back)) {
343 		WARN_ON(1);
344 		return 0;
345 	}
346 
347 	/* remove it from vmemmap_list */
348 	if (vmem_back == vmemmap_list) /* remove head */
349 		vmemmap_list = vmem_back->list;
350 	else
351 		vmem_back_prev->list = vmem_back->list;
352 
353 	/* next point to this freed entry */
354 	vmem_back->list = next;
355 	next = vmem_back;
356 	num_freed++;
357 
358 	return vmem_back->phys;
359 }
360 
361 void __ref vmemmap_free(unsigned long start, unsigned long end)
362 {
363 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
364 
365 	start = _ALIGN_DOWN(start, page_size);
366 
367 	pr_debug("vmemmap_free %lx...%lx\n", start, end);
368 
369 	for (; start < end; start += page_size) {
370 		unsigned long addr;
371 
372 		/*
373 		 * the section has already be marked as invalid, so
374 		 * vmemmap_populated() true means some other sections still
375 		 * in this page, so skip it.
376 		 */
377 		if (vmemmap_populated(start, page_size))
378 			continue;
379 
380 		addr = vmemmap_list_free(start);
381 		if (addr) {
382 			struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
383 
384 			if (PageReserved(page)) {
385 				/* allocated from bootmem */
386 				if (page_size < PAGE_SIZE) {
387 					/*
388 					 * this shouldn't happen, but if it is
389 					 * the case, leave the memory there
390 					 */
391 					WARN_ON_ONCE(1);
392 				} else {
393 					unsigned int nr_pages =
394 						1 << get_order(page_size);
395 					while (nr_pages--)
396 						free_reserved_page(page++);
397 				}
398 			} else
399 				free_pages((unsigned long)(__va(addr)),
400 							get_order(page_size));
401 
402 			vmemmap_remove_mapping(start, page_size);
403 		}
404 	}
405 }
406 #endif
407 void register_page_bootmem_memmap(unsigned long section_nr,
408 				  struct page *start_page, unsigned long size)
409 {
410 }
411 
412 /*
413  * We do not have access to the sparsemem vmemmap, so we fallback to
414  * walking the list of sparsemem blocks which we already maintain for
415  * the sake of crashdump. In the long run, we might want to maintain
416  * a tree if performance of that linear walk becomes a problem.
417  *
418  * realmode_pfn_to_page functions can fail due to:
419  * 1) As real sparsemem blocks do not lay in RAM continously (they
420  * are in virtual address space which is not available in the real mode),
421  * the requested page struct can be split between blocks so get_page/put_page
422  * may fail.
423  * 2) When huge pages are used, the get_page/put_page API will fail
424  * in real mode as the linked addresses in the page struct are virtual
425  * too.
426  */
427 struct page *realmode_pfn_to_page(unsigned long pfn)
428 {
429 	struct vmemmap_backing *vmem_back;
430 	struct page *page;
431 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
432 	unsigned long pg_va = (unsigned long) pfn_to_page(pfn);
433 
434 	for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) {
435 		if (pg_va < vmem_back->virt_addr)
436 			continue;
437 
438 		/* After vmemmap_list entry free is possible, need check all */
439 		if ((pg_va + sizeof(struct page)) <=
440 				(vmem_back->virt_addr + page_size)) {
441 			page = (struct page *) (vmem_back->phys + pg_va -
442 				vmem_back->virt_addr);
443 			return page;
444 		}
445 	}
446 
447 	/* Probably that page struct is split between real pages */
448 	return NULL;
449 }
450 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
451 
452 #elif defined(CONFIG_FLATMEM)
453 
454 struct page *realmode_pfn_to_page(unsigned long pfn)
455 {
456 	struct page *page = pfn_to_page(pfn);
457 	return page;
458 }
459 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
460 
461 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */
462