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 #ifdef CONFIG_PPC_STD_MMU_64 72 #if H_PGTABLE_RANGE > USER_VSID_RANGE 73 #warning Limited user VSID range means pagetable space is wasted 74 #endif 75 #endif /* CONFIG_PPC_STD_MMU_64 */ 76 77 phys_addr_t memstart_addr = ~0; 78 EXPORT_SYMBOL_GPL(memstart_addr); 79 phys_addr_t kernstart_addr; 80 EXPORT_SYMBOL_GPL(kernstart_addr); 81 82 #ifdef CONFIG_SPARSEMEM_VMEMMAP 83 /* 84 * Given an address within the vmemmap, determine the pfn of the page that 85 * represents the start of the section it is within. Note that we have to 86 * do this by hand as the proffered address may not be correctly aligned. 87 * Subtraction of non-aligned pointers produces undefined results. 88 */ 89 static unsigned long __meminit vmemmap_section_start(unsigned long page) 90 { 91 unsigned long offset = page - ((unsigned long)(vmemmap)); 92 93 /* Return the pfn of the start of the section. */ 94 return (offset / sizeof(struct page)) & PAGE_SECTION_MASK; 95 } 96 97 /* 98 * Check if this vmemmap page is already initialised. If any section 99 * which overlaps this vmemmap page is initialised then this page is 100 * initialised already. 101 */ 102 static int __meminit vmemmap_populated(unsigned long start, int page_size) 103 { 104 unsigned long end = start + page_size; 105 start = (unsigned long)(pfn_to_page(vmemmap_section_start(start))); 106 107 for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) 108 if (pfn_valid(page_to_pfn((struct page *)start))) 109 return 1; 110 111 return 0; 112 } 113 114 /* 115 * vmemmap virtual address space management does not have a traditonal page 116 * table to track which virtual struct pages are backed by physical mapping. 117 * The virtual to physical mappings are tracked in a simple linked list 118 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at 119 * all times where as the 'next' list maintains the available 120 * vmemmap_backing structures which have been deleted from the 121 * 'vmemmap_global' list during system runtime (memory hotplug remove 122 * operation). The freed 'vmemmap_backing' structures are reused later when 123 * new requests come in without allocating fresh memory. This pointer also 124 * tracks the allocated 'vmemmap_backing' structures as we allocate one 125 * full page memory at a time when we dont have any. 126 */ 127 struct vmemmap_backing *vmemmap_list; 128 static struct vmemmap_backing *next; 129 130 /* 131 * The same pointer 'next' tracks individual chunks inside the allocated 132 * full page during the boot time and again tracks the freeed nodes during 133 * runtime. It is racy but it does not happen as they are separated by the 134 * boot process. Will create problem if some how we have memory hotplug 135 * operation during boot !! 136 */ 137 static int num_left; 138 static int num_freed; 139 140 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) 141 { 142 struct vmemmap_backing *vmem_back; 143 /* get from freed entries first */ 144 if (num_freed) { 145 num_freed--; 146 vmem_back = next; 147 next = next->list; 148 149 return vmem_back; 150 } 151 152 /* allocate a page when required and hand out chunks */ 153 if (!num_left) { 154 next = vmemmap_alloc_block(PAGE_SIZE, node); 155 if (unlikely(!next)) { 156 WARN_ON(1); 157 return NULL; 158 } 159 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); 160 } 161 162 num_left--; 163 164 return next++; 165 } 166 167 static __meminit void vmemmap_list_populate(unsigned long phys, 168 unsigned long start, 169 int node) 170 { 171 struct vmemmap_backing *vmem_back; 172 173 vmem_back = vmemmap_list_alloc(node); 174 if (unlikely(!vmem_back)) { 175 WARN_ON(1); 176 return; 177 } 178 179 vmem_back->phys = phys; 180 vmem_back->virt_addr = start; 181 vmem_back->list = vmemmap_list; 182 183 vmemmap_list = vmem_back; 184 } 185 186 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) 187 { 188 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 189 190 /* Align to the page size of the linear mapping. */ 191 start = _ALIGN_DOWN(start, page_size); 192 193 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); 194 195 for (; start < end; start += page_size) { 196 struct vmem_altmap *altmap; 197 void *p; 198 int rc; 199 200 if (vmemmap_populated(start, page_size)) 201 continue; 202 203 /* altmap lookups only work at section boundaries */ 204 altmap = to_vmem_altmap(SECTION_ALIGN_DOWN(start)); 205 206 p = __vmemmap_alloc_block_buf(page_size, node, altmap); 207 if (!p) 208 return -ENOMEM; 209 210 vmemmap_list_populate(__pa(p), start, node); 211 212 pr_debug(" * %016lx..%016lx allocated at %p\n", 213 start, start + page_size, p); 214 215 rc = vmemmap_create_mapping(start, page_size, __pa(p)); 216 if (rc < 0) { 217 pr_warning( 218 "vmemmap_populate: Unable to create vmemmap mapping: %d\n", 219 rc); 220 return -EFAULT; 221 } 222 } 223 224 return 0; 225 } 226 227 #ifdef CONFIG_MEMORY_HOTPLUG 228 static unsigned long vmemmap_list_free(unsigned long start) 229 { 230 struct vmemmap_backing *vmem_back, *vmem_back_prev; 231 232 vmem_back_prev = vmem_back = vmemmap_list; 233 234 /* look for it with prev pointer recorded */ 235 for (; vmem_back; vmem_back = vmem_back->list) { 236 if (vmem_back->virt_addr == start) 237 break; 238 vmem_back_prev = vmem_back; 239 } 240 241 if (unlikely(!vmem_back)) { 242 WARN_ON(1); 243 return 0; 244 } 245 246 /* remove it from vmemmap_list */ 247 if (vmem_back == vmemmap_list) /* remove head */ 248 vmemmap_list = vmem_back->list; 249 else 250 vmem_back_prev->list = vmem_back->list; 251 252 /* next point to this freed entry */ 253 vmem_back->list = next; 254 next = vmem_back; 255 num_freed++; 256 257 return vmem_back->phys; 258 } 259 260 void __ref vmemmap_free(unsigned long start, unsigned long end) 261 { 262 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 263 unsigned long page_order = get_order(page_size); 264 265 start = _ALIGN_DOWN(start, page_size); 266 267 pr_debug("vmemmap_free %lx...%lx\n", start, end); 268 269 for (; start < end; start += page_size) { 270 unsigned long nr_pages, addr; 271 struct vmem_altmap *altmap; 272 struct page *section_base; 273 struct page *page; 274 275 /* 276 * the section has already be marked as invalid, so 277 * vmemmap_populated() true means some other sections still 278 * in this page, so skip it. 279 */ 280 if (vmemmap_populated(start, page_size)) 281 continue; 282 283 addr = vmemmap_list_free(start); 284 if (!addr) 285 continue; 286 287 page = pfn_to_page(addr >> PAGE_SHIFT); 288 section_base = pfn_to_page(vmemmap_section_start(start)); 289 nr_pages = 1 << page_order; 290 291 altmap = to_vmem_altmap((unsigned long) section_base); 292 if (altmap) { 293 vmem_altmap_free(altmap, nr_pages); 294 } else if (PageReserved(page)) { 295 /* allocated from bootmem */ 296 if (page_size < PAGE_SIZE) { 297 /* 298 * this shouldn't happen, but if it is 299 * the case, leave the memory there 300 */ 301 WARN_ON_ONCE(1); 302 } else { 303 while (nr_pages--) 304 free_reserved_page(page++); 305 } 306 } else { 307 free_pages((unsigned long)(__va(addr)), page_order); 308 } 309 310 vmemmap_remove_mapping(start, page_size); 311 } 312 } 313 #endif 314 void register_page_bootmem_memmap(unsigned long section_nr, 315 struct page *start_page, unsigned long size) 316 { 317 } 318 319 /* 320 * We do not have access to the sparsemem vmemmap, so we fallback to 321 * walking the list of sparsemem blocks which we already maintain for 322 * the sake of crashdump. In the long run, we might want to maintain 323 * a tree if performance of that linear walk becomes a problem. 324 * 325 * realmode_pfn_to_page functions can fail due to: 326 * 1) As real sparsemem blocks do not lay in RAM continously (they 327 * are in virtual address space which is not available in the real mode), 328 * the requested page struct can be split between blocks so get_page/put_page 329 * may fail. 330 * 2) When huge pages are used, the get_page/put_page API will fail 331 * in real mode as the linked addresses in the page struct are virtual 332 * too. 333 */ 334 struct page *realmode_pfn_to_page(unsigned long pfn) 335 { 336 struct vmemmap_backing *vmem_back; 337 struct page *page; 338 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 339 unsigned long pg_va = (unsigned long) pfn_to_page(pfn); 340 341 for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) { 342 if (pg_va < vmem_back->virt_addr) 343 continue; 344 345 /* After vmemmap_list entry free is possible, need check all */ 346 if ((pg_va + sizeof(struct page)) <= 347 (vmem_back->virt_addr + page_size)) { 348 page = (struct page *) (vmem_back->phys + pg_va - 349 vmem_back->virt_addr); 350 return page; 351 } 352 } 353 354 /* Probably that page struct is split between real pages */ 355 return NULL; 356 } 357 EXPORT_SYMBOL_GPL(realmode_pfn_to_page); 358 359 #else 360 361 struct page *realmode_pfn_to_page(unsigned long pfn) 362 { 363 struct page *page = pfn_to_page(pfn); 364 return page; 365 } 366 EXPORT_SYMBOL_GPL(realmode_pfn_to_page); 367 368 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 369 370 #ifdef CONFIG_PPC_STD_MMU_64 371 static bool disable_radix; 372 static int __init parse_disable_radix(char *p) 373 { 374 disable_radix = true; 375 return 0; 376 } 377 early_param("disable_radix", parse_disable_radix); 378 379 /* 380 * If we're running under a hypervisor, we need to check the contents of 381 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do 382 * radix. If not, we clear the radix feature bit so we fall back to hash. 383 */ 384 static void __init early_check_vec5(void) 385 { 386 unsigned long root, chosen; 387 int size; 388 const u8 *vec5; 389 u8 mmu_supported; 390 391 root = of_get_flat_dt_root(); 392 chosen = of_get_flat_dt_subnode_by_name(root, "chosen"); 393 if (chosen == -FDT_ERR_NOTFOUND) { 394 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 395 return; 396 } 397 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size); 398 if (!vec5) { 399 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 400 return; 401 } 402 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) { 403 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 404 return; 405 } 406 407 /* Check for supported configuration */ 408 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] & 409 OV5_FEAT(OV5_MMU_SUPPORT); 410 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) { 411 /* Hypervisor only supports radix - check enabled && GTSE */ 412 if (!early_radix_enabled()) { 413 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 414 } 415 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] & 416 OV5_FEAT(OV5_RADIX_GTSE))) { 417 pr_warn("WARNING: Hypervisor doesn't support RADIX with GTSE\n"); 418 } 419 /* Do radix anyway - the hypervisor said we had to */ 420 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX; 421 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) { 422 /* Hypervisor only supports hash - disable radix */ 423 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 424 } 425 } 426 427 void __init mmu_early_init_devtree(void) 428 { 429 /* Disable radix mode based on kernel command line. */ 430 if (disable_radix) 431 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 432 433 /* 434 * Check /chosen/ibm,architecture-vec-5 if running as a guest. 435 * When running bare-metal, we can use radix if we like 436 * even though the ibm,architecture-vec-5 property created by 437 * skiboot doesn't have the necessary bits set. 438 */ 439 if (!(mfmsr() & MSR_HV)) 440 early_check_vec5(); 441 442 if (early_radix_enabled()) 443 radix__early_init_devtree(); 444 else 445 hash__early_init_devtree(); 446 } 447 #endif /* CONFIG_PPC_STD_MMU_64 */ 448