3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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
9 * Derived from "arch/i386/mm/init.c"
10 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
12 * Dave Engebretsen <engebret@us.ibm.com>
13 * Rework for PPC64 port.
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.
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>
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>
46 #include <asm/pgalloc.h>
51 #include <asm/mmu_context.h>
52 #include <asm/pgtable.h>
54 #include <asm/uaccess.h>
56 #include <asm/machdep.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>
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
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.
76 #endif /* CONFIG_PPC_STD_MMU_64 */
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);
83 static void pgd_ctor(void *addr)
85 memset(addr, 0, PGD_TABLE_SIZE);
88 static void pud_ctor(void *addr)
90 memset(addr, 0, PUD_TABLE_SIZE);
93 static void pmd_ctor(void *addr)
95 memset(addr, 0, PMD_TABLE_SIZE);
98 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
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.
107 void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
110 unsigned long table_size = sizeof(void *) << shift;
111 unsigned long align = table_size;
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.
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;
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));
130 if (PGT_CACHE(shift))
131 return; /* Already have a cache of this size */
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);
137 pgtable_cache[shift - 1] = new;
138 pr_debug("Allocated pgtable cache for order %d\n", shift);
142 void pgtable_cache_init(void)
144 pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
145 pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
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
151 if (PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE))
152 pgtable_cache_add(PUD_INDEX_SIZE, pud_ctor);
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");
160 #ifdef CONFIG_SPARSEMEM_VMEMMAP
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.
167 static unsigned long __meminit vmemmap_section_start(unsigned long page)
169 unsigned long offset = page - ((unsigned long)(vmemmap));
171 /* Return the pfn of the start of the section. */
172 return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
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.
180 static int __meminit vmemmap_populated(unsigned long start, int page_size)
182 unsigned long end = start + page_size;
183 start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
185 for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
186 if (pfn_valid(page_to_pfn((struct page *)start)))
192 struct vmemmap_backing *vmemmap_list;
193 static struct vmemmap_backing *next;
195 static int num_freed;
197 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
199 struct vmemmap_backing *vmem_back;
200 /* get from freed entries first */
209 /* allocate a page when required and hand out chunks */
211 next = vmemmap_alloc_block(PAGE_SIZE, node);
212 if (unlikely(!next)) {
216 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
224 static __meminit void vmemmap_list_populate(unsigned long phys,
228 struct vmemmap_backing *vmem_back;
230 vmem_back = vmemmap_list_alloc(node);
231 if (unlikely(!vmem_back)) {
236 vmem_back->phys = phys;
237 vmem_back->virt_addr = start;
238 vmem_back->list = vmemmap_list;
240 vmemmap_list = vmem_back;
243 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
245 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
247 /* Align to the page size of the linear mapping. */
248 start = _ALIGN_DOWN(start, page_size);
250 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
252 for (; start < end; start += page_size) {
256 if (vmemmap_populated(start, page_size))
259 p = vmemmap_alloc_block(page_size, node);
263 vmemmap_list_populate(__pa(p), start, node);
265 pr_debug(" * %016lx..%016lx allocated at %p\n",
266 start, start + page_size, p);
268 rc = vmemmap_create_mapping(start, page_size, __pa(p));
271 "vmemmap_populate: Unable to create vmemmap mapping: %d\n",
280 #ifdef CONFIG_MEMORY_HOTPLUG
281 static unsigned long vmemmap_list_free(unsigned long start)
283 struct vmemmap_backing *vmem_back, *vmem_back_prev;
285 vmem_back_prev = vmem_back = vmemmap_list;
287 /* look for it with prev pointer recorded */
288 for (; vmem_back; vmem_back = vmem_back->list) {
289 if (vmem_back->virt_addr == start)
291 vmem_back_prev = vmem_back;
294 if (unlikely(!vmem_back)) {
299 /* remove it from vmemmap_list */
300 if (vmem_back == vmemmap_list) /* remove head */
301 vmemmap_list = vmem_back->list;
303 vmem_back_prev->list = vmem_back->list;
305 /* next point to this freed entry */
306 vmem_back->list = next;
310 return vmem_back->phys;
313 void __ref vmemmap_free(unsigned long start, unsigned long end)
315 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
317 start = _ALIGN_DOWN(start, page_size);
319 pr_debug("vmemmap_free %lx...%lx\n", start, end);
321 for (; start < end; start += page_size) {
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.
329 if (vmemmap_populated(start, page_size))
332 addr = vmemmap_list_free(start);
334 struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
336 if (PageReserved(page)) {
337 /* allocated from bootmem */
338 if (page_size < PAGE_SIZE) {
340 * this shouldn't happen, but if it is
341 * the case, leave the memory there
345 unsigned int nr_pages =
346 1 << get_order(page_size);
348 free_reserved_page(page++);
351 free_pages((unsigned long)(__va(addr)),
352 get_order(page_size));
354 vmemmap_remove_mapping(start, page_size);
359 void register_page_bootmem_memmap(unsigned long section_nr,
360 struct page *start_page, unsigned long size)
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.
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
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
379 struct page *realmode_pfn_to_page(unsigned long pfn)
381 struct vmemmap_backing *vmem_back;
383 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
384 unsigned long pg_va = (unsigned long) pfn_to_page(pfn);
386 for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) {
387 if (pg_va < vmem_back->virt_addr)
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);
399 /* Probably that page struct is split between real pages */
402 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
404 #elif defined(CONFIG_FLATMEM)
406 struct page *realmode_pfn_to_page(unsigned long pfn)
408 struct page *page = pfn_to_page(pfn);
411 EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
413 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */