1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 7 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 8 * Copyright (C) 1996 Paul Mackerras 9 * 10 * Derived from "arch/i386/mm/init.c" 11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 12 * 13 * Dave Engebretsen <engebret@us.ibm.com> 14 * Rework for PPC64 port. 15 */ 16 17 #undef DEBUG 18 19 #include <linux/signal.h> 20 #include <linux/sched.h> 21 #include <linux/kernel.h> 22 #include <linux/errno.h> 23 #include <linux/string.h> 24 #include <linux/types.h> 25 #include <linux/mman.h> 26 #include <linux/mm.h> 27 #include <linux/swap.h> 28 #include <linux/stddef.h> 29 #include <linux/vmalloc.h> 30 #include <linux/init.h> 31 #include <linux/delay.h> 32 #include <linux/highmem.h> 33 #include <linux/idr.h> 34 #include <linux/nodemask.h> 35 #include <linux/module.h> 36 #include <linux/poison.h> 37 #include <linux/memblock.h> 38 #include <linux/hugetlb.h> 39 #include <linux/slab.h> 40 #include <linux/of_fdt.h> 41 #include <linux/libfdt.h> 42 #include <linux/memremap.h> 43 44 #include <asm/pgalloc.h> 45 #include <asm/page.h> 46 #include <asm/prom.h> 47 #include <asm/rtas.h> 48 #include <asm/io.h> 49 #include <asm/mmu_context.h> 50 #include <asm/mmu.h> 51 #include <linux/uaccess.h> 52 #include <asm/smp.h> 53 #include <asm/machdep.h> 54 #include <asm/tlb.h> 55 #include <asm/eeh.h> 56 #include <asm/processor.h> 57 #include <asm/mmzone.h> 58 #include <asm/cputable.h> 59 #include <asm/sections.h> 60 #include <asm/iommu.h> 61 #include <asm/vdso.h> 62 63 #include <mm/mmu_decl.h> 64 65 #ifdef CONFIG_SPARSEMEM_VMEMMAP 66 /* 67 * Given an address within the vmemmap, determine the page that 68 * represents the start of the subsection it is within. Note that we have to 69 * do this by hand as the proffered address may not be correctly aligned. 70 * Subtraction of non-aligned pointers produces undefined results. 71 */ 72 static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_addr) 73 { 74 unsigned long start_pfn; 75 unsigned long offset = vmemmap_addr - ((unsigned long)(vmemmap)); 76 77 /* Return the pfn of the start of the section. */ 78 start_pfn = (offset / sizeof(struct page)) & PAGE_SUBSECTION_MASK; 79 return pfn_to_page(start_pfn); 80 } 81 82 /* 83 * Since memory is added in sub-section chunks, before creating a new vmemmap 84 * mapping, the kernel should check whether there is an existing memmap mapping 85 * covering the new subsection added. This is needed because kernel can map 86 * vmemmap area using 16MB pages which will cover a memory range of 16G. Such 87 * a range covers multiple subsections (2M) 88 * 89 * If any subsection in the 16G range mapped by vmemmap is valid we consider the 90 * vmemmap populated (There is a page table entry already present). We can't do 91 * a page table lookup here because with the hash translation we don't keep 92 * vmemmap details in linux page table. 93 */ 94 static int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size) 95 { 96 struct page *start; 97 unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size; 98 start = vmemmap_subsection_start(vmemmap_addr); 99 100 for (; (unsigned long)start < vmemmap_end; start += PAGES_PER_SUBSECTION) 101 /* 102 * pfn valid check here is intended to really check 103 * whether we have any subsection already initialized 104 * in this range. 105 */ 106 if (pfn_valid(page_to_pfn(start))) 107 return 1; 108 109 return 0; 110 } 111 112 /* 113 * vmemmap virtual address space management does not have a traditonal page 114 * table to track which virtual struct pages are backed by physical mapping. 115 * The virtual to physical mappings are tracked in a simple linked list 116 * format. 'vmemmap_list' maintains the entire vmemmap physical mapping at 117 * all times where as the 'next' list maintains the available 118 * vmemmap_backing structures which have been deleted from the 119 * 'vmemmap_global' list during system runtime (memory hotplug remove 120 * operation). The freed 'vmemmap_backing' structures are reused later when 121 * new requests come in without allocating fresh memory. This pointer also 122 * tracks the allocated 'vmemmap_backing' structures as we allocate one 123 * full page memory at a time when we dont have any. 124 */ 125 struct vmemmap_backing *vmemmap_list; 126 static struct vmemmap_backing *next; 127 128 /* 129 * The same pointer 'next' tracks individual chunks inside the allocated 130 * full page during the boot time and again tracks the freeed nodes during 131 * runtime. It is racy but it does not happen as they are separated by the 132 * boot process. Will create problem if some how we have memory hotplug 133 * operation during boot !! 134 */ 135 static int num_left; 136 static int num_freed; 137 138 static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) 139 { 140 struct vmemmap_backing *vmem_back; 141 /* get from freed entries first */ 142 if (num_freed) { 143 num_freed--; 144 vmem_back = next; 145 next = next->list; 146 147 return vmem_back; 148 } 149 150 /* allocate a page when required and hand out chunks */ 151 if (!num_left) { 152 next = vmemmap_alloc_block(PAGE_SIZE, node); 153 if (unlikely(!next)) { 154 WARN_ON(1); 155 return NULL; 156 } 157 num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); 158 } 159 160 num_left--; 161 162 return next++; 163 } 164 165 static __meminit void vmemmap_list_populate(unsigned long phys, 166 unsigned long start, 167 int node) 168 { 169 struct vmemmap_backing *vmem_back; 170 171 vmem_back = vmemmap_list_alloc(node); 172 if (unlikely(!vmem_back)) { 173 WARN_ON(1); 174 return; 175 } 176 177 vmem_back->phys = phys; 178 vmem_back->virt_addr = start; 179 vmem_back->list = vmemmap_list; 180 181 vmemmap_list = vmem_back; 182 } 183 184 static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start, 185 unsigned long page_size) 186 { 187 unsigned long nr_pfn = page_size / sizeof(struct page); 188 unsigned long start_pfn = page_to_pfn((struct page *)start); 189 190 if ((start_pfn + nr_pfn) > altmap->end_pfn) 191 return true; 192 193 if (start_pfn < altmap->base_pfn) 194 return true; 195 196 return false; 197 } 198 199 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 200 struct vmem_altmap *altmap) 201 { 202 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 203 204 /* Align to the page size of the linear mapping. */ 205 start = ALIGN_DOWN(start, page_size); 206 207 pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node); 208 209 for (; start < end; start += page_size) { 210 void *p = NULL; 211 int rc; 212 213 /* 214 * This vmemmap range is backing different subsections. If any 215 * of that subsection is marked valid, that means we already 216 * have initialized a page table covering this range and hence 217 * the vmemmap range is populated. 218 */ 219 if (vmemmap_populated(start, page_size)) 220 continue; 221 222 /* 223 * Allocate from the altmap first if we have one. This may 224 * fail due to alignment issues when using 16MB hugepages, so 225 * fall back to system memory if the altmap allocation fail. 226 */ 227 if (altmap && !altmap_cross_boundary(altmap, start, page_size)) { 228 p = altmap_alloc_block_buf(page_size, altmap); 229 if (!p) 230 pr_debug("altmap block allocation failed, falling back to system memory"); 231 } 232 if (!p) 233 p = vmemmap_alloc_block_buf(page_size, node); 234 if (!p) 235 return -ENOMEM; 236 237 vmemmap_list_populate(__pa(p), start, node); 238 239 pr_debug(" * %016lx..%016lx allocated at %p\n", 240 start, start + page_size, p); 241 242 rc = vmemmap_create_mapping(start, page_size, __pa(p)); 243 if (rc < 0) { 244 pr_warn("%s: Unable to create vmemmap mapping: %d\n", 245 __func__, rc); 246 return -EFAULT; 247 } 248 } 249 250 return 0; 251 } 252 253 #ifdef CONFIG_MEMORY_HOTPLUG 254 static unsigned long vmemmap_list_free(unsigned long start) 255 { 256 struct vmemmap_backing *vmem_back, *vmem_back_prev; 257 258 vmem_back_prev = vmem_back = vmemmap_list; 259 260 /* look for it with prev pointer recorded */ 261 for (; vmem_back; vmem_back = vmem_back->list) { 262 if (vmem_back->virt_addr == start) 263 break; 264 vmem_back_prev = vmem_back; 265 } 266 267 if (unlikely(!vmem_back)) { 268 WARN_ON(1); 269 return 0; 270 } 271 272 /* remove it from vmemmap_list */ 273 if (vmem_back == vmemmap_list) /* remove head */ 274 vmemmap_list = vmem_back->list; 275 else 276 vmem_back_prev->list = vmem_back->list; 277 278 /* next point to this freed entry */ 279 vmem_back->list = next; 280 next = vmem_back; 281 num_freed++; 282 283 return vmem_back->phys; 284 } 285 286 void __ref vmemmap_free(unsigned long start, unsigned long end, 287 struct vmem_altmap *altmap) 288 { 289 unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; 290 unsigned long page_order = get_order(page_size); 291 unsigned long alt_start = ~0, alt_end = ~0; 292 unsigned long base_pfn; 293 294 start = ALIGN_DOWN(start, page_size); 295 if (altmap) { 296 alt_start = altmap->base_pfn; 297 alt_end = altmap->base_pfn + altmap->reserve + 298 altmap->free + altmap->alloc + altmap->align; 299 } 300 301 pr_debug("vmemmap_free %lx...%lx\n", start, end); 302 303 for (; start < end; start += page_size) { 304 unsigned long nr_pages, addr; 305 struct page *page; 306 307 /* 308 * We have already marked the subsection we are trying to remove 309 * invalid. So if we want to remove the vmemmap range, we 310 * need to make sure there is no subsection marked valid 311 * in this range. 312 */ 313 if (vmemmap_populated(start, page_size)) 314 continue; 315 316 addr = vmemmap_list_free(start); 317 if (!addr) 318 continue; 319 320 page = pfn_to_page(addr >> PAGE_SHIFT); 321 nr_pages = 1 << page_order; 322 base_pfn = PHYS_PFN(addr); 323 324 if (base_pfn >= alt_start && base_pfn < alt_end) { 325 vmem_altmap_free(altmap, nr_pages); 326 } else if (PageReserved(page)) { 327 /* allocated from bootmem */ 328 if (page_size < PAGE_SIZE) { 329 /* 330 * this shouldn't happen, but if it is 331 * the case, leave the memory there 332 */ 333 WARN_ON_ONCE(1); 334 } else { 335 while (nr_pages--) 336 free_reserved_page(page++); 337 } 338 } else { 339 free_pages((unsigned long)(__va(addr)), page_order); 340 } 341 342 vmemmap_remove_mapping(start, page_size); 343 } 344 } 345 #endif 346 void register_page_bootmem_memmap(unsigned long section_nr, 347 struct page *start_page, unsigned long size) 348 { 349 } 350 351 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 352 353 #ifdef CONFIG_PPC_BOOK3S_64 354 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT); 355 356 static int __init parse_disable_radix(char *p) 357 { 358 bool val; 359 360 if (!p) 361 val = true; 362 else if (kstrtobool(p, &val)) 363 return -EINVAL; 364 365 disable_radix = val; 366 367 return 0; 368 } 369 early_param("disable_radix", parse_disable_radix); 370 371 /* 372 * If we're running under a hypervisor, we need to check the contents of 373 * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do 374 * radix. If not, we clear the radix feature bit so we fall back to hash. 375 */ 376 static void __init early_check_vec5(void) 377 { 378 unsigned long root, chosen; 379 int size; 380 const u8 *vec5; 381 u8 mmu_supported; 382 383 root = of_get_flat_dt_root(); 384 chosen = of_get_flat_dt_subnode_by_name(root, "chosen"); 385 if (chosen == -FDT_ERR_NOTFOUND) { 386 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 387 return; 388 } 389 vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size); 390 if (!vec5) { 391 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 392 return; 393 } 394 if (size <= OV5_INDX(OV5_MMU_SUPPORT)) { 395 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 396 return; 397 } 398 399 /* Check for supported configuration */ 400 mmu_supported = vec5[OV5_INDX(OV5_MMU_SUPPORT)] & 401 OV5_FEAT(OV5_MMU_SUPPORT); 402 if (mmu_supported == OV5_FEAT(OV5_MMU_RADIX)) { 403 /* Hypervisor only supports radix - check enabled && GTSE */ 404 if (!early_radix_enabled()) { 405 pr_warn("WARNING: Ignoring cmdline option disable_radix\n"); 406 } 407 if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] & 408 OV5_FEAT(OV5_RADIX_GTSE))) { 409 pr_warn("WARNING: Hypervisor doesn't support RADIX with GTSE\n"); 410 } 411 /* Do radix anyway - the hypervisor said we had to */ 412 cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX; 413 } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) { 414 /* Hypervisor only supports hash - disable radix */ 415 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 416 } 417 } 418 419 void __init mmu_early_init_devtree(void) 420 { 421 /* Disable radix mode based on kernel command line. */ 422 if (disable_radix) 423 cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX; 424 425 /* 426 * Check /chosen/ibm,architecture-vec-5 if running as a guest. 427 * When running bare-metal, we can use radix if we like 428 * even though the ibm,architecture-vec-5 property created by 429 * skiboot doesn't have the necessary bits set. 430 */ 431 if (!(mfmsr() & MSR_HV)) 432 early_check_vec5(); 433 434 if (early_radix_enabled()) 435 radix__early_init_devtree(); 436 else 437 hash__early_init_devtree(); 438 } 439 #endif /* CONFIG_PPC_BOOK3S_64 */ 440