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 #include <linux/of_fdt.h>
46 #include <linux/libfdt.h>
47 #include <linux/memremap.h>
48
49 #include <asm/pgalloc.h>
50 #include <asm/page.h>
51 #include <asm/prom.h>
52 #include <asm/rtas.h>
53 #include <asm/io.h>
54 #include <asm/mmu_context.h>
55 #include <asm/pgtable.h>
56 #include <asm/mmu.h>
57 #include <linux/uaccess.h>
58 #include <asm/smp.h>
59 #include <asm/machdep.h>
60 #include <asm/tlb.h>
61 #include <asm/eeh.h>
62 #include <asm/processor.h>
63 #include <asm/mmzone.h>
64 #include <asm/cputable.h>
65 #include <asm/sections.h>
66 #include <asm/iommu.h>
67 #include <asm/vdso.h>
68
69 #include "mmu_decl.h"
70
71 phys_addr_t memstart_addr = ~0;
72 EXPORT_SYMBOL_GPL(memstart_addr);
73 phys_addr_t kernstart_addr;
74 EXPORT_SYMBOL_GPL(kernstart_addr);
75
76 #ifdef CONFIG_SPARSEMEM_VMEMMAP
77 /*
78 * Given an address within the vmemmap, determine the pfn of the page that
79 * represents the start of the section it is within. Note that we have to
80 * do this by hand as the proffered address may not be correctly aligned.
81 * Subtraction of non-aligned pointers produces undefined results.
82 */
vmemmap_section_start(unsigned long page)83 static unsigned long __meminit vmemmap_section_start(unsigned long page)
84 {
85 unsigned long offset = page - ((unsigned long)(vmemmap));
86
87 /* Return the pfn of the start of the section. */
88 return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
89 }
90
91 /*
92 * Check if this vmemmap page is already initialised. If any section
93 * which overlaps this vmemmap page is initialised then this page is
94 * initialised already.
95 */
vmemmap_populated(unsigned long start,int page_size)96 static int __meminit vmemmap_populated(unsigned long start, int page_size)
97 {
98 unsigned long end = start + page_size;
99 start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
100
101 for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
102 if (pfn_valid(page_to_pfn((struct page *)start)))
103 return 1;
104
105 return 0;
106 }
107
108 /*
109 * vmemmap virtual address space management does not have a traditonal page
110 * table to track which virtual struct pages are backed by physical mapping.
111 * The virtual to physical mappings are tracked in a simple linked list
112 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at
113 * all times where as the 'next' list maintains the available
114 * vmemmap_backing structures which have been deleted from the
115 * 'vmemmap_global' list during system runtime (memory hotplug remove
116 * operation). The freed 'vmemmap_backing' structures are reused later when
117 * new requests come in without allocating fresh memory. This pointer also
118 * tracks the allocated 'vmemmap_backing' structures as we allocate one
119 * full page memory at a time when we dont have any.
120 */
121 struct vmemmap_backing *vmemmap_list;
122 static struct vmemmap_backing *next;
123
124 /*
125 * The same pointer 'next' tracks individual chunks inside the allocated
126 * full page during the boot time and again tracks the freeed nodes during
127 * runtime. It is racy but it does not happen as they are separated by the
128 * boot process. Will create problem if some how we have memory hotplug
129 * operation during boot !!
130 */
131 static int num_left;
132 static int num_freed;
133
vmemmap_list_alloc(int node)134 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node)
135 {
136 struct vmemmap_backing *vmem_back;
137 /* get from freed entries first */
138 if (num_freed) {
139 num_freed--;
140 vmem_back = next;
141 next = next->list;
142
143 return vmem_back;
144 }
145
146 /* allocate a page when required and hand out chunks */
147 if (!num_left) {
148 next = vmemmap_alloc_block(PAGE_SIZE, node);
149 if (unlikely(!next)) {
150 WARN_ON(1);
151 return NULL;
152 }
153 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing);
154 }
155
156 num_left--;
157
158 return next++;
159 }
160
vmemmap_list_populate(unsigned long phys,unsigned long start,int node)161 static __meminit void vmemmap_list_populate(unsigned long phys,
162 unsigned long start,
163 int node)
164 {
165 struct vmemmap_backing *vmem_back;
166
167 vmem_back = vmemmap_list_alloc(node);
168 if (unlikely(!vmem_back)) {
169 WARN_ON(1);
170 return;
171 }
172
173 vmem_back->phys = phys;
174 vmem_back->virt_addr = start;
175 vmem_back->list = vmemmap_list;
176
177 vmemmap_list = vmem_back;
178 }
179
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)180 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
181 struct vmem_altmap *altmap)
182 {
183 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
184
185 /* Align to the page size of the linear mapping. */
186 start = _ALIGN_DOWN(start, page_size);
187
188 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
189
190 for (; start < end; start += page_size) {
191 void *p;
192 int rc;
193
194 if (vmemmap_populated(start, page_size))
195 continue;
196
197 if (altmap)
198 p = altmap_alloc_block_buf(page_size, altmap);
199 else
200 p = vmemmap_alloc_block_buf(page_size, node);
201 if (!p)
202 return -ENOMEM;
203
204 vmemmap_list_populate(__pa(p), start, node);
205
206 pr_debug(" * %016lx..%016lx allocated at %p\n",
207 start, start + page_size, p);
208
209 rc = vmemmap_create_mapping(start, page_size, __pa(p));
210 if (rc < 0) {
211 pr_warn("%s: Unable to create vmemmap mapping: %d\n",
212 __func__, rc);
213 return -EFAULT;
214 }
215 }
216
217 return 0;
218 }
219
220 #ifdef CONFIG_MEMORY_HOTPLUG
vmemmap_list_free(unsigned long start)221 static unsigned long vmemmap_list_free(unsigned long start)
222 {
223 struct vmemmap_backing *vmem_back, *vmem_back_prev;
224
225 vmem_back_prev = vmem_back = vmemmap_list;
226
227 /* look for it with prev pointer recorded */
228 for (; vmem_back; vmem_back = vmem_back->list) {
229 if (vmem_back->virt_addr == start)
230 break;
231 vmem_back_prev = vmem_back;
232 }
233
234 if (unlikely(!vmem_back)) {
235 WARN_ON(1);
236 return 0;
237 }
238
239 /* remove it from vmemmap_list */
240 if (vmem_back == vmemmap_list) /* remove head */
241 vmemmap_list = vmem_back->list;
242 else
243 vmem_back_prev->list = vmem_back->list;
244
245 /* next point to this freed entry */
246 vmem_back->list = next;
247 next = vmem_back;
248 num_freed++;
249
250 return vmem_back->phys;
251 }
252
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)253 void __ref vmemmap_free(unsigned long start, unsigned long end,
254 struct vmem_altmap *altmap)
255 {
256 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
257 unsigned long page_order = get_order(page_size);
258
259 start = _ALIGN_DOWN(start, page_size);
260
261 pr_debug("vmemmap_free %lx...%lx\n", start, end);
262
263 for (; start < end; start += page_size) {
264 unsigned long nr_pages, addr;
265 struct page *section_base;
266 struct page *page;
267
268 /*
269 * the section has already be marked as invalid, so
270 * vmemmap_populated() true means some other sections still
271 * in this page, so skip it.
272 */
273 if (vmemmap_populated(start, page_size))
274 continue;
275
276 addr = vmemmap_list_free(start);
277 if (!addr)
278 continue;
279
280 page = pfn_to_page(addr >> PAGE_SHIFT);
281 section_base = pfn_to_page(vmemmap_section_start(start));
282 nr_pages = 1 << page_order;
283
284 if (altmap) {
285 vmem_altmap_free(altmap, nr_pages);
286 } else if (PageReserved(page)) {
287 /* allocated from bootmem */
288 if (page_size < PAGE_SIZE) {
289 /*
290 * this shouldn't happen, but if it is
291 * the case, leave the memory there
292 */
293 WARN_ON_ONCE(1);
294 } else {
295 while (nr_pages--)
296 free_reserved_page(page++);
297 }
298 } else {
299 free_pages((unsigned long)(__va(addr)), page_order);
300 }
301
302 vmemmap_remove_mapping(start, page_size);
303 }
304 }
305 #endif
register_page_bootmem_memmap(unsigned long section_nr,struct page * start_page,unsigned long size)306 void register_page_bootmem_memmap(unsigned long section_nr,
307 struct page *start_page, unsigned long size)
308 {
309 }
310
311 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
312
313 #ifdef CONFIG_PPC_BOOK3S_64
314 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT);
315
parse_disable_radix(char * p)316 static int __init parse_disable_radix(char *p)
317 {
318 bool val;
319
320 if (!p)
321 val = true;
322 else if (kstrtobool(p, &val))
323 return -EINVAL;
324
325 disable_radix = val;
326
327 return 0;
328 }
329 early_param("disable_radix", parse_disable_radix);
330
331 /*
332 * If we're running under a hypervisor, we need to check the contents of
333 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do
334 * radix. If not, we clear the radix feature bit so we fall back to hash.
335 */
early_check_vec5(void)336 static void __init early_check_vec5(void)
337 {
338 unsigned long root, chosen;
339 int size;
340 const u8 *vec5;
341 u8 mmu_supported;
342
343 root = of_get_flat_dt_root();
344 chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
345 if (chosen == -FDT_ERR_NOTFOUND) {
346 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
347 return;
348 }
349 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
350 if (!vec5) {
351 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
352 return;
353 }
354 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) {
355 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
356 return;
357 }
358
359 /* Check for supported configuration */
360 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] &
361 OV5_FEAT(OV5_MMU_SUPPORT);
362 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) {
363 /* Hypervisor only supports radix - check enabled && GTSE */
364 if (!early_radix_enabled()) {
365 pr_warn("WARNING: Ignoring cmdline option disable_radix\n");
366 }
367 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] &
368 OV5_FEAT(OV5_RADIX_GTSE))) {
369 pr_warn("WARNING: Hypervisor doesn't support RADIX with GTSE\n");
370 }
371 /* Do radix anyway - the hypervisor said we had to */
372 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX;
373 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) {
374 /* Hypervisor only supports hash - disable radix */
375 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
376 }
377 }
378
mmu_early_init_devtree(void)379 void __init mmu_early_init_devtree(void)
380 {
381 /* Disable radix mode based on kernel command line. */
382 if (disable_radix)
383 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
384
385 /*
386 * Check /chosen/ibm,architecture-vec-5 if running as a guest.
387 * When running bare-metal, we can use radix if we like
388 * even though the ibm,architecture-vec-5 property created by
389 * skiboot doesn't have the necessary bits set.
390 */
391 if (!(mfmsr() & MSR_HV))
392 early_check_vec5();
393
394 if (early_radix_enabled())
395 radix__early_init_devtree();
396 else
397 hash__early_init_devtree();
398 }
399 #endif /* CONFIG_PPC_BOOK3S_64 */
400
