1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Virtual Memory Map support
4 *
5 * (C) 2007 sgi. Christoph Lameter.
6 *
7 * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
8 * virt_to_page, page_address() to be implemented as a base offset
9 * calculation without memory access.
10 *
11 * However, virtual mappings need a page table and TLBs. Many Linux
12 * architectures already map their physical space using 1-1 mappings
13 * via TLBs. For those arches the virtual memory map is essentially
14 * for free if we use the same page size as the 1-1 mappings. In that
15 * case the overhead consists of a few additional pages that are
16 * allocated to create a view of memory for vmemmap.
17 *
18 * The architecture is expected to provide a vmemmap_populate() function
19 * to instantiate the mapping.
20 */
21 #include <linux/mm.h>
22 #include <linux/mmzone.h>
23 #include <linux/memblock.h>
24 #include <linux/memremap.h>
25 #include <linux/highmem.h>
26 #include <linux/slab.h>
27 #include <linux/spinlock.h>
28 #include <linux/vmalloc.h>
29 #include <linux/sched.h>
30 #include <asm/dma.h>
31 #include <asm/pgalloc.h>
32 #include <asm/pgtable.h>
33
34 /*
35 * Allocate a block of memory to be used to back the virtual memory map
36 * or to back the page tables that are used to create the mapping.
37 * Uses the main allocators if they are available, else bootmem.
38 */
39
__earlyonly_bootmem_alloc(int node,unsigned long size,unsigned long align,unsigned long goal)40 static void * __ref __earlyonly_bootmem_alloc(int node,
41 unsigned long size,
42 unsigned long align,
43 unsigned long goal)
44 {
45 return memblock_alloc_try_nid_raw(size, align, goal,
46 MEMBLOCK_ALLOC_ACCESSIBLE, node);
47 }
48
vmemmap_alloc_block(unsigned long size,int node)49 void * __meminit vmemmap_alloc_block(unsigned long size, int node)
50 {
51 /* If the main allocator is up use that, fallback to bootmem. */
52 if (slab_is_available()) {
53 gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
54 int order = get_order(size);
55 static bool warned;
56 struct page *page;
57
58 page = alloc_pages_node(node, gfp_mask, order);
59 if (page)
60 return page_address(page);
61
62 if (!warned) {
63 warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,
64 "vmemmap alloc failure: order:%u", order);
65 warned = true;
66 }
67 return NULL;
68 } else
69 return __earlyonly_bootmem_alloc(node, size, size,
70 __pa(MAX_DMA_ADDRESS));
71 }
72
73 /* need to make sure size is all the same during early stage */
vmemmap_alloc_block_buf(unsigned long size,int node)74 void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
75 {
76 void *ptr = sparse_buffer_alloc(size);
77
78 if (!ptr)
79 ptr = vmemmap_alloc_block(size, node);
80 return ptr;
81 }
82
vmem_altmap_next_pfn(struct vmem_altmap * altmap)83 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
84 {
85 return altmap->base_pfn + altmap->reserve + altmap->alloc
86 + altmap->align;
87 }
88
vmem_altmap_nr_free(struct vmem_altmap * altmap)89 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
90 {
91 unsigned long allocated = altmap->alloc + altmap->align;
92
93 if (altmap->free > allocated)
94 return altmap->free - allocated;
95 return 0;
96 }
97
98 /**
99 * altmap_alloc_block_buf - allocate pages from the device page map
100 * @altmap: device page map
101 * @size: size (in bytes) of the allocation
102 *
103 * Allocations are aligned to the size of the request.
104 */
altmap_alloc_block_buf(unsigned long size,struct vmem_altmap * altmap)105 void * __meminit altmap_alloc_block_buf(unsigned long size,
106 struct vmem_altmap *altmap)
107 {
108 unsigned long pfn, nr_pfns, nr_align;
109
110 if (size & ~PAGE_MASK) {
111 pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
112 __func__, size);
113 return NULL;
114 }
115
116 pfn = vmem_altmap_next_pfn(altmap);
117 nr_pfns = size >> PAGE_SHIFT;
118 nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
119 nr_align = ALIGN(pfn, nr_align) - pfn;
120 if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
121 return NULL;
122
123 altmap->alloc += nr_pfns;
124 altmap->align += nr_align;
125 pfn += nr_align;
126
127 pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
128 __func__, pfn, altmap->alloc, altmap->align, nr_pfns);
129 return __va(__pfn_to_phys(pfn));
130 }
131
vmemmap_verify(pte_t * pte,int node,unsigned long start,unsigned long end)132 void __meminit vmemmap_verify(pte_t *pte, int node,
133 unsigned long start, unsigned long end)
134 {
135 unsigned long pfn = pte_pfn(*pte);
136 int actual_node = early_pfn_to_nid(pfn);
137
138 if (node_distance(actual_node, node) > LOCAL_DISTANCE)
139 pr_warn("[%lx-%lx] potential offnode page_structs\n",
140 start, end - 1);
141 }
142
vmemmap_pte_populate(pmd_t * pmd,unsigned long addr,int node)143 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
144 {
145 pte_t *pte = pte_offset_kernel(pmd, addr);
146 if (pte_none(*pte)) {
147 pte_t entry;
148 void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
149 if (!p)
150 return NULL;
151 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
152 set_pte_at(&init_mm, addr, pte, entry);
153 }
154 return pte;
155 }
156
vmemmap_alloc_block_zero(unsigned long size,int node)157 static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
158 {
159 void *p = vmemmap_alloc_block(size, node);
160
161 if (!p)
162 return NULL;
163 memset(p, 0, size);
164
165 return p;
166 }
167
vmemmap_pmd_populate(pud_t * pud,unsigned long addr,int node)168 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
169 {
170 pmd_t *pmd = pmd_offset(pud, addr);
171 if (pmd_none(*pmd)) {
172 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
173 if (!p)
174 return NULL;
175 pmd_populate_kernel(&init_mm, pmd, p);
176 }
177 return pmd;
178 }
179
vmemmap_pud_populate(p4d_t * p4d,unsigned long addr,int node)180 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
181 {
182 pud_t *pud = pud_offset(p4d, addr);
183 if (pud_none(*pud)) {
184 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
185 if (!p)
186 return NULL;
187 pud_populate(&init_mm, pud, p);
188 }
189 return pud;
190 }
191
vmemmap_p4d_populate(pgd_t * pgd,unsigned long addr,int node)192 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
193 {
194 p4d_t *p4d = p4d_offset(pgd, addr);
195 if (p4d_none(*p4d)) {
196 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
197 if (!p)
198 return NULL;
199 p4d_populate(&init_mm, p4d, p);
200 }
201 return p4d;
202 }
203
vmemmap_pgd_populate(unsigned long addr,int node)204 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
205 {
206 pgd_t *pgd = pgd_offset_k(addr);
207 if (pgd_none(*pgd)) {
208 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
209 if (!p)
210 return NULL;
211 pgd_populate(&init_mm, pgd, p);
212 }
213 return pgd;
214 }
215
vmemmap_populate_basepages(unsigned long start,unsigned long end,int node)216 int __meminit vmemmap_populate_basepages(unsigned long start,
217 unsigned long end, int node)
218 {
219 unsigned long addr = start;
220 pgd_t *pgd;
221 p4d_t *p4d;
222 pud_t *pud;
223 pmd_t *pmd;
224 pte_t *pte;
225
226 for (; addr < end; addr += PAGE_SIZE) {
227 pgd = vmemmap_pgd_populate(addr, node);
228 if (!pgd)
229 return -ENOMEM;
230 p4d = vmemmap_p4d_populate(pgd, addr, node);
231 if (!p4d)
232 return -ENOMEM;
233 pud = vmemmap_pud_populate(p4d, addr, node);
234 if (!pud)
235 return -ENOMEM;
236 pmd = vmemmap_pmd_populate(pud, addr, node);
237 if (!pmd)
238 return -ENOMEM;
239 pte = vmemmap_pte_populate(pmd, addr, node);
240 if (!pte)
241 return -ENOMEM;
242 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
243 }
244
245 return 0;
246 }
247
__populate_section_memmap(unsigned long pfn,unsigned long nr_pages,int nid,struct vmem_altmap * altmap)248 struct page * __meminit __populate_section_memmap(unsigned long pfn,
249 unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
250 {
251 unsigned long start;
252 unsigned long end;
253
254 /*
255 * The minimum granularity of memmap extensions is
256 * PAGES_PER_SUBSECTION as allocations are tracked in the
257 * 'subsection_map' bitmap of the section.
258 */
259 end = ALIGN(pfn + nr_pages, PAGES_PER_SUBSECTION);
260 pfn &= PAGE_SUBSECTION_MASK;
261 nr_pages = end - pfn;
262
263 start = (unsigned long) pfn_to_page(pfn);
264 end = start + nr_pages * sizeof(struct page);
265
266 if (vmemmap_populate(start, end, nid, altmap))
267 return NULL;
268
269 return pfn_to_page(pfn);
270 }
271
