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
33 /*
34 * Allocate a block of memory to be used to back the virtual memory map
35 * or to back the page tables that are used to create the mapping.
36 * Uses the main allocators if they are available, else bootmem.
37 */
38
__earlyonly_bootmem_alloc(int node,unsigned long size,unsigned long align,unsigned long goal)39 static void * __ref __earlyonly_bootmem_alloc(int node,
40 unsigned long size,
41 unsigned long align,
42 unsigned long goal)
43 {
44 return memblock_alloc_try_nid_raw(size, align, goal,
45 MEMBLOCK_ALLOC_ACCESSIBLE, node);
46 }
47
vmemmap_alloc_block(unsigned long size,int node)48 void * __meminit vmemmap_alloc_block(unsigned long size, int node)
49 {
50 /* If the main allocator is up use that, fallback to bootmem. */
51 if (slab_is_available()) {
52 gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
53 int order = get_order(size);
54 static bool warned;
55 struct page *page;
56
57 page = alloc_pages_node(node, gfp_mask, order);
58 if (page)
59 return page_address(page);
60
61 if (!warned) {
62 warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,
63 "vmemmap alloc failure: order:%u", order);
64 warned = true;
65 }
66 return NULL;
67 } else
68 return __earlyonly_bootmem_alloc(node, size, size,
69 __pa(MAX_DMA_ADDRESS));
70 }
71
72 static void * __meminit altmap_alloc_block_buf(unsigned long size,
73 struct vmem_altmap *altmap);
74
75 /* need to make sure size is all the same during early stage */
vmemmap_alloc_block_buf(unsigned long size,int node,struct vmem_altmap * altmap)76 void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node,
77 struct vmem_altmap *altmap)
78 {
79 void *ptr;
80
81 if (altmap)
82 return altmap_alloc_block_buf(size, altmap);
83
84 ptr = sparse_buffer_alloc(size);
85 if (!ptr)
86 ptr = vmemmap_alloc_block(size, node);
87 return ptr;
88 }
89
vmem_altmap_next_pfn(struct vmem_altmap * altmap)90 static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
91 {
92 return altmap->base_pfn + altmap->reserve + altmap->alloc
93 + altmap->align;
94 }
95
vmem_altmap_nr_free(struct vmem_altmap * altmap)96 static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
97 {
98 unsigned long allocated = altmap->alloc + altmap->align;
99
100 if (altmap->free > allocated)
101 return altmap->free - allocated;
102 return 0;
103 }
104
altmap_alloc_block_buf(unsigned long size,struct vmem_altmap * altmap)105 static 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,struct vmem_altmap * altmap)143 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
144 struct vmem_altmap *altmap)
145 {
146 pte_t *pte = pte_offset_kernel(pmd, addr);
147 if (pte_none(*pte)) {
148 pte_t entry;
149 void *p;
150
151 p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap);
152 if (!p)
153 return NULL;
154 entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
155 set_pte_at(&init_mm, addr, pte, entry);
156 }
157 return pte;
158 }
159
vmemmap_alloc_block_zero(unsigned long size,int node)160 static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
161 {
162 void *p = vmemmap_alloc_block(size, node);
163
164 if (!p)
165 return NULL;
166 memset(p, 0, size);
167
168 return p;
169 }
170
vmemmap_pmd_populate(pud_t * pud,unsigned long addr,int node)171 pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
172 {
173 pmd_t *pmd = pmd_offset(pud, addr);
174 if (pmd_none(*pmd)) {
175 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
176 if (!p)
177 return NULL;
178 pmd_populate_kernel(&init_mm, pmd, p);
179 }
180 return pmd;
181 }
182
vmemmap_pud_populate(p4d_t * p4d,unsigned long addr,int node)183 pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
184 {
185 pud_t *pud = pud_offset(p4d, addr);
186 if (pud_none(*pud)) {
187 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
188 if (!p)
189 return NULL;
190 pud_populate(&init_mm, pud, p);
191 }
192 return pud;
193 }
194
vmemmap_p4d_populate(pgd_t * pgd,unsigned long addr,int node)195 p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
196 {
197 p4d_t *p4d = p4d_offset(pgd, addr);
198 if (p4d_none(*p4d)) {
199 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
200 if (!p)
201 return NULL;
202 p4d_populate(&init_mm, p4d, p);
203 }
204 return p4d;
205 }
206
vmemmap_pgd_populate(unsigned long addr,int node)207 pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
208 {
209 pgd_t *pgd = pgd_offset_k(addr);
210 if (pgd_none(*pgd)) {
211 void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
212 if (!p)
213 return NULL;
214 pgd_populate(&init_mm, pgd, p);
215 }
216 return pgd;
217 }
218
vmemmap_populate_basepages(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)219 int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
220 int node, struct vmem_altmap *altmap)
221 {
222 unsigned long addr = start;
223 pgd_t *pgd;
224 p4d_t *p4d;
225 pud_t *pud;
226 pmd_t *pmd;
227 pte_t *pte;
228
229 for (; addr < end; addr += PAGE_SIZE) {
230 pgd = vmemmap_pgd_populate(addr, node);
231 if (!pgd)
232 return -ENOMEM;
233 p4d = vmemmap_p4d_populate(pgd, addr, node);
234 if (!p4d)
235 return -ENOMEM;
236 pud = vmemmap_pud_populate(p4d, addr, node);
237 if (!pud)
238 return -ENOMEM;
239 pmd = vmemmap_pmd_populate(pud, addr, node);
240 if (!pmd)
241 return -ENOMEM;
242 pte = vmemmap_pte_populate(pmd, addr, node, altmap);
243 if (!pte)
244 return -ENOMEM;
245 vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
246 }
247
248 return 0;
249 }
250
__populate_section_memmap(unsigned long pfn,unsigned long nr_pages,int nid,struct vmem_altmap * altmap)251 struct page * __meminit __populate_section_memmap(unsigned long pfn,
252 unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
253 {
254 unsigned long start = (unsigned long) pfn_to_page(pfn);
255 unsigned long end = start + nr_pages * sizeof(struct page);
256
257 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) ||
258 !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION)))
259 return NULL;
260
261 if (vmemmap_populate(start, end, nid, altmap))
262 return NULL;
263
264 return pfn_to_page(pfn);
265 }
266