xref: /openbmc/linux/arch/powerpc/mm/init_64.c (revision de2bdb3d)
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 H_PGTABLE_RANGE > USER_VSID_RANGE
70 #warning Limited user VSID range means pagetable space is wasted
71 #endif
72 
73 #if (TASK_SIZE_USER64 < H_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 pud_ctor(void *addr)
89 {
90 	memset(addr, 0, PUD_TABLE_SIZE);
91 }
92 
93 static void pmd_ctor(void *addr)
94 {
95 	memset(addr, 0, PMD_TABLE_SIZE);
96 }
97 
98 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
99 
100 /*
101  * Create a kmem_cache() for pagetables.  This is not used for PTE
102  * pages - they're linked to struct page, come from the normal free
103  * pages pool and have a different entry size (see real_pte_t) to
104  * everything else.  Caches created by this function are used for all
105  * the higher level pagetables, and for hugepage pagetables.
106  */
107 void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
108 {
109 	char *name;
110 	unsigned long table_size = sizeof(void *) << shift;
111 	unsigned long align = table_size;
112 
113 	/* When batching pgtable pointers for RCU freeing, we store
114 	 * the index size in the low bits.  Table alignment must be
115 	 * big enough to fit it.
116 	 *
117 	 * Likewise, hugeapge pagetable pointers contain a (different)
118 	 * shift value in the low bits.  All tables must be aligned so
119 	 * as to leave enough 0 bits in the address to contain it. */
120 	unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
121 				     HUGEPD_SHIFT_MASK + 1);
122 	struct kmem_cache *new;
123 
124 	/* It would be nice if this was a BUILD_BUG_ON(), but at the
125 	 * moment, gcc doesn't seem to recognize is_power_of_2 as a
126 	 * constant expression, so so much for that. */
127 	BUG_ON(!is_power_of_2(minalign));
128 	BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
129 
130 	if (PGT_CACHE(shift))
131 		return; /* Already have a cache of this size */
132 
133 	align = max_t(unsigned long, align, minalign);
134 	name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
135 	new = kmem_cache_create(name, table_size, align, 0, ctor);
136 	kfree(name);
137 	pgtable_cache[shift - 1] = new;
138 	pr_debug("Allocated pgtable cache for order %d\n", shift);
139 }
140 
141 
142 void pgtable_cache_init(void)
143 {
144 	pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
145 	pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
146 	/*
147 	 * In all current configs, when the PUD index exists it's the
148 	 * same size as either the pgd or pmd index except with THP enabled
149 	 * on book3s 64
150 	 */
151 	if (PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE))
152 		pgtable_cache_add(PUD_INDEX_SIZE, pud_ctor);
153 
154 	if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_CACHE_INDEX))
155 		panic("Couldn't allocate pgtable caches");
156 	if (PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE))
157 		panic("Couldn't allocate pud pgtable caches");
158 }
159 
160 #ifdef CONFIG_SPARSEMEM_VMEMMAP
161 /*
162  * Given an address within the vmemmap, determine the pfn of the page that
163  * represents the start of the section it is within.  Note that we have to
164  * do this by hand as the proffered address may not be correctly aligned.
165  * Subtraction of non-aligned pointers produces undefined results.
166  */
167 static unsigned long __meminit vmemmap_section_start(unsigned long page)
168 {
169 	unsigned long offset = page - ((unsigned long)(vmemmap));
170 
171 	/* Return the pfn of the start of the section. */
172 	return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
173 }
174 
175 /*
176  * Check if this vmemmap page is already initialised.  If any section
177  * which overlaps this vmemmap page is initialised then this page is
178  * initialised already.
179  */
180 static int __meminit vmemmap_populated(unsigned long start, int page_size)
181 {
182 	unsigned long end = start + page_size;
183 	start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
184 
185 	for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
186 		if (pfn_valid(page_to_pfn((struct page *)start)))
187 			return 1;
188 
189 	return 0;
190 }
191 
192 struct vmemmap_backing *vmemmap_list;
193 static struct vmemmap_backing *next;
194 static int num_left;
195 static int num_freed;
196 
197 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
198 {
199 	struct vmemmap_backing *vmem_back;
200 	/* get from freed entries first */
201 	if (num_freed) {
202 		num_freed--;
203 		vmem_back = next;
204 		next = next->list;
205 
206 		return vmem_back;
207 	}
208 
209 	/* allocate a page when required and hand out chunks */
210 	if (!num_left) {
211 		next = vmemmap_alloc_block(PAGE_SIZE, node);
212 		if (unlikely(!next)) {
213 			WARN_ON(1);
214 			return NULL;
215 		}
216 		num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
217 	}
218 
219 	num_left--;
220 
221 	return next++;
222 }
223 
224 static __meminit void vmemmap_list_populate(unsigned long phys,
225 					    unsigned long start,
226 					    int node)
227 {
228 	struct vmemmap_backing *vmem_back;
229 
230 	vmem_back = vmemmap_list_alloc(node);
231 	if (unlikely(!vmem_back)) {
232 		WARN_ON(1);
233 		return;
234 	}
235 
236 	vmem_back->phys = phys;
237 	vmem_back->virt_addr = start;
238 	vmem_back->list = vmemmap_list;
239 
240 	vmemmap_list = vmem_back;
241 }
242 
243 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
244 {
245 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
246 
247 	/* Align to the page size of the linear mapping. */
248 	start = _ALIGN_DOWN(start, page_size);
249 
250 	pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
251 
252 	for (; start < end; start += page_size) {
253 		void *p;
254 		int rc;
255 
256 		if (vmemmap_populated(start, page_size))
257 			continue;
258 
259 		p = vmemmap_alloc_block(page_size, node);
260 		if (!p)
261 			return -ENOMEM;
262 
263 		vmemmap_list_populate(__pa(p), start, node);
264 
265 		pr_debug("      * %016lx..%016lx allocated at %p\n",
266 			 start, start + page_size, p);
267 
268 		rc = vmemmap_create_mapping(start, page_size, __pa(p));
269 		if (rc < 0) {
270 			pr_warning(
271 				"vmemmap_populate: Unable to create vmemmap mapping: %d\n",
272 				rc);
273 			return -EFAULT;
274 		}
275 	}
276 
277 	return 0;
278 }
279 
280 #ifdef CONFIG_MEMORY_HOTPLUG
281 static unsigned long vmemmap_list_free(unsigned long start)
282 {
283 	struct vmemmap_backing *vmem_back, *vmem_back_prev;
284 
285 	vmem_back_prev = vmem_back = vmemmap_list;
286 
287 	/* look for it with prev pointer recorded */
288 	for (; vmem_back; vmem_back = vmem_back->list) {
289 		if (vmem_back->virt_addr == start)
290 			break;
291 		vmem_back_prev = vmem_back;
292 	}
293 
294 	if (unlikely(!vmem_back)) {
295 		WARN_ON(1);
296 		return 0;
297 	}
298 
299 	/* remove it from vmemmap_list */
300 	if (vmem_back == vmemmap_list) /* remove head */
301 		vmemmap_list = vmem_back->list;
302 	else
303 		vmem_back_prev->list = vmem_back->list;
304 
305 	/* next point to this freed entry */
306 	vmem_back->list = next;
307 	next = vmem_back;
308 	num_freed++;
309 
310 	return vmem_back->phys;
311 }
312 
313 void __ref vmemmap_free(unsigned long start, unsigned long end)
314 {
315 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
316 
317 	start = _ALIGN_DOWN(start, page_size);
318 
319 	pr_debug("vmemmap_free %lx...%lx\n", start, end);
320 
321 	for (; start < end; start += page_size) {
322 		unsigned long addr;
323 
324 		/*
325 		 * the section has already be marked as invalid, so
326 		 * vmemmap_populated() true means some other sections still
327 		 * in this page, so skip it.
328 		 */
329 		if (vmemmap_populated(start, page_size))
330 			continue;
331 
332 		addr = vmemmap_list_free(start);
333 		if (addr) {
334 			struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
335 
336 			if (PageReserved(page)) {
337 				/* allocated from bootmem */
338 				if (page_size < PAGE_SIZE) {
339 					/*
340 					 * this shouldn't happen, but if it is
341 					 * the case, leave the memory there
342 					 */
343 					WARN_ON_ONCE(1);
344 				} else {
345 					unsigned int nr_pages =
346 						1 << get_order(page_size);
347 					while (nr_pages--)
348 						free_reserved_page(page++);
349 				}
350 			} else
351 				free_pages((unsigned long)(__va(addr)),
352 							get_order(page_size));
353 
354 			vmemmap_remove_mapping(start, page_size);
355 		}
356 	}
357 }
358 #endif
359 void register_page_bootmem_memmap(unsigned long section_nr,
360 				  struct page *start_page, unsigned long size)
361 {
362 }
363 
364 /*
365  * We do not have access to the sparsemem vmemmap, so we fallback to
366  * walking the list of sparsemem blocks which we already maintain for
367  * the sake of crashdump. In the long run, we might want to maintain
368  * a tree if performance of that linear walk becomes a problem.
369  *
370  * realmode_pfn_to_page functions can fail due to:
371  * 1) As real sparsemem blocks do not lay in RAM continously (they
372  * are in virtual address space which is not available in the real mode),
373  * the requested page struct can be split between blocks so get_page/put_page
374  * may fail.
375  * 2) When huge pages are used, the get_page/put_page API will fail
376  * in real mode as the linked addresses in the page struct are virtual
377  * too.
378  */
379 struct page *realmode_pfn_to_page(unsigned long pfn)
380 {
381 	struct vmemmap_backing *vmem_back;
382 	struct page *page;
383 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
384 	unsigned long pg_va = (unsigned long) pfn_to_page(pfn);
385 
386 	for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) {
387 		if (pg_va < vmem_back->virt_addr)
388 			continue;
389 
390 		/* After vmemmap_list entry free is possible, need check all */
391 		if ((pg_va + sizeof(struct page)) <=
392 				(vmem_back->virt_addr + page_size)) {
393 			page = (struct page *) (vmem_back->phys + pg_va -
394 				vmem_back->virt_addr);
395 			return page;
396 		}
397 	}
398 
399 	/* Probably that page struct is split between real pages */
400 	return NULL;
401 }
402 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
403 
404 #elif defined(CONFIG_FLATMEM)
405 
406 struct page *realmode_pfn_to_page(unsigned long pfn)
407 {
408 	struct page *page = pfn_to_page(pfn);
409 	return page;
410 }
411 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
412 
413 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */
414 
415 #ifdef CONFIG_PPC_STD_MMU_64
416 static bool disable_radix;
417 static int __init parse_disable_radix(char *p)
418 {
419 	disable_radix = true;
420 	return 0;
421 }
422 early_param("disable_radix", parse_disable_radix);
423 
424 void __init mmu_early_init_devtree(void)
425 {
426 	/* Disable radix mode based on kernel command line. */
427 	if (disable_radix)
428 		cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
429 
430 	if (early_radix_enabled())
431 		radix__early_init_devtree();
432 	else
433 		hash__early_init_devtree();
434 }
435 #endif /* CONFIG_PPC_STD_MMU_64 */
436