arch/powerpc/mm/pgtable-radix.c

   1 /*
   2  * Page table handling routines for radix page table.
   3  *
   4  * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <linux/sched.h>
  12 #include <linux/memblock.h>
  13 #include <linux/of_fdt.h>
  14
  15 #include <asm/pgtable.h>
  16 #include <asm/pgalloc.h>
  17 #include <asm/dma.h>
  18 #include <asm/machdep.h>
  19 #include <asm/mmu.h>
  20 #include <asm/firmware.h>
  21
  22 #include <trace/events/thp.h>
  23
  24 static int native_register_process_table(unsigned long base, unsigned long pg_sz,
  25                                          unsigned long table_size)
  26 {
  27         unsigned long patb1 = base | table_size | PATB_GR;
  28
  29         partition_tb->patb1 = cpu_to_be64(patb1);
  30         return 0;
  31 }
  32
  33 static __ref void *early_alloc_pgtable(unsigned long size)
  34 {
  35         void *pt;
  36
  37         pt = __va(memblock_alloc_base(size, size, MEMBLOCK_ALLOC_ANYWHERE));
  38         memset(pt, 0, size);
  39
  40         return pt;
  41 }
  42
  43 int radix__map_kernel_page(unsigned long ea, unsigned long pa,
  44                           pgprot_t flags,
  45                           unsigned int map_page_size)
  46 {
  47         pgd_t *pgdp;
  48         pud_t *pudp;
  49         pmd_t *pmdp;
  50         pte_t *ptep;
  51         /*
  52          * Make sure task size is correct as per the max adddr
  53          */
  54         BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);
  55         if (slab_is_available()) {
  56                 pgdp = pgd_offset_k(ea);
  57                 pudp = pud_alloc(&init_mm, pgdp, ea);
  58                 if (!pudp)
  59                         return -ENOMEM;
  60                 if (map_page_size == PUD_SIZE) {
  61                         ptep = (pte_t *)pudp;
  62                         goto set_the_pte;
  63                 }
  64                 pmdp = pmd_alloc(&init_mm, pudp, ea);
  65                 if (!pmdp)
  66                         return -ENOMEM;
  67                 if (map_page_size == PMD_SIZE) {
  68                         ptep = (pte_t *)pudp;
  69                         goto set_the_pte;
  70                 }
  71                 ptep = pte_alloc_kernel(pmdp, ea);
  72                 if (!ptep)
  73                         return -ENOMEM;
  74         } else {
  75                 pgdp = pgd_offset_k(ea);
  76                 if (pgd_none(*pgdp)) {
  77                         pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
  78                         BUG_ON(pudp == NULL);
  79                         pgd_populate(&init_mm, pgdp, pudp);
  80                 }
  81                 pudp = pud_offset(pgdp, ea);
  82                 if (map_page_size == PUD_SIZE) {
  83                         ptep = (pte_t *)pudp;
  84                         goto set_the_pte;
  85                 }
  86                 if (pud_none(*pudp)) {
  87                         pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
  88                         BUG_ON(pmdp == NULL);
  89                         pud_populate(&init_mm, pudp, pmdp);
  90                 }
  91                 pmdp = pmd_offset(pudp, ea);
  92                 if (map_page_size == PMD_SIZE) {
  93                         ptep = (pte_t *)pudp;
  94                         goto set_the_pte;
  95                 }
  96                 if (!pmd_present(*pmdp)) {
  97                         ptep = early_alloc_pgtable(PAGE_SIZE);
  98                         BUG_ON(ptep == NULL);
  99                         pmd_populate_kernel(&init_mm, pmdp, ptep);
 100                 }
 101                 ptep = pte_offset_kernel(pmdp, ea);
 102         }
 103
 104 set_the_pte:
 105         set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, flags));
 106         smp_wmb();
 107         return 0;
 108 }
 109
 110 static void __init radix_init_pgtable(void)
 111 {
 112         int loop_count;
 113         u64 base, end, start_addr;
 114         unsigned long rts_field;
 115         struct memblock_region *reg;
 116         unsigned long linear_page_size;
 117
 118         /* We don't support slb for radix */
 119         mmu_slb_size = 0;
 120         /*
 121          * Create the linear mapping, using standard page size for now
 122          */
 123         loop_count = 0;
 124         for_each_memblock(memory, reg) {
 125
 126                 start_addr = reg->base;
 127
 128 redo:
 129                 if (loop_count < 1 && mmu_psize_defs[MMU_PAGE_1G].shift)
 130                         linear_page_size = PUD_SIZE;
 131                 else if (loop_count < 2 && mmu_psize_defs[MMU_PAGE_2M].shift)
 132                         linear_page_size = PMD_SIZE;
 133                 else
 134                         linear_page_size = PAGE_SIZE;
 135
 136                 base = _ALIGN_UP(start_addr, linear_page_size);
 137                 end = _ALIGN_DOWN(reg->base + reg->size, linear_page_size);
 138
 139                 pr_info("Mapping range 0x%lx - 0x%lx with 0x%lx\n",
 140                         (unsigned long)base, (unsigned long)end,
 141                         linear_page_size);
 142
 143                 while (base < end) {
 144                         radix__map_kernel_page((unsigned long)__va(base),
 145                                               base, PAGE_KERNEL_X,
 146                                               linear_page_size);
 147                         base += linear_page_size;
 148                 }
 149                 /*
 150                  * map the rest using lower page size
 151                  */
 152                 if (end < reg->base + reg->size) {
 153                         start_addr = end;
 154                         loop_count++;
 155                         goto redo;
 156                 }
 157         }
 158         /*
 159          * Allocate Partition table and process table for the
 160          * host.
 161          */
 162         BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 23), "Process table size too large.");
 163         process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
 164         /*
 165          * Fill in the process table.
 166          */
 167         rts_field = radix__get_tree_size();
 168         process_tb->prtb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) | RADIX_PGD_INDEX_SIZE);
 169         /*
 170          * Fill in the partition table. We are suppose to use effective address
 171          * of process table here. But our linear mapping also enable us to use
 172          * physical address here.
 173          */
 174         register_process_table(__pa(process_tb), 0, PRTB_SIZE_SHIFT - 12);
 175         pr_info("Process table %p and radix root for kernel: %p\n", process_tb, init_mm.pgd);
 176 }
 177
 178 static void __init radix_init_partition_table(void)
 179 {
 180         unsigned long rts_field;
 181
 182         rts_field = radix__get_tree_size();
 183
 184         BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 24), "Partition table size too large.");
 185         partition_tb = early_alloc_pgtable(1UL << PATB_SIZE_SHIFT);
 186         partition_tb->patb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) |
 187                                           RADIX_PGD_INDEX_SIZE | PATB_HR);
 188         pr_info("Initializing Radix MMU\n");
 189         pr_info("Partition table %p\n", partition_tb);
 190
 191         memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
 192         /*
 193          * update partition table control register,
 194          * 64 K size.
 195          */
 196         mtspr(SPRN_PTCR, __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
 197 }
 198
 199 void __init radix_init_native(void)
 200 {
 201         register_process_table = native_register_process_table;
 202 }
 203
 204 static int __init get_idx_from_shift(unsigned int shift)
 205 {
 206         int idx = -1;
 207
 208         switch (shift) {
 209         case 0xc:
 210                 idx = MMU_PAGE_4K;
 211                 break;
 212         case 0x10:
 213                 idx = MMU_PAGE_64K;
 214                 break;
 215         case 0x15:
 216                 idx = MMU_PAGE_2M;
 217                 break;
 218         case 0x1e:
 219                 idx = MMU_PAGE_1G;
 220                 break;
 221         }
 222         return idx;
 223 }
 224
 225 static int __init radix_dt_scan_page_sizes(unsigned long node,
 226                                            const char *uname, int depth,
 227                                            void *data)
 228 {
 229         int size = 0;
 230         int shift, idx;
 231         unsigned int ap;
 232         const __be32 *prop;
 233         const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 234
 235         /* We are scanning "cpu" nodes only */
 236         if (type == NULL || strcmp(type, "cpu") != 0)
 237                 return 0;
 238
 239         prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
 240         if (!prop)
 241                 return 0;
 242
 243         pr_info("Page sizes from device-tree:\n");
 244         for (; size >= 4; size -= 4, ++prop) {
 245
 246                 struct mmu_psize_def *def;
 247
 248                 /* top 3 bit is AP encoding */
 249                 shift = be32_to_cpu(prop[0]) & ~(0xe << 28);
 250                 ap = be32_to_cpu(prop[0]) >> 29;
 251                 pr_info("Page size sift = %d AP=0x%x\n", shift, ap);
 252
 253                 idx = get_idx_from_shift(shift);
 254                 if (idx < 0)
 255                         continue;
 256
 257                 def = &mmu_psize_defs[idx];
 258                 def->shift = shift;
 259                 def->ap  = ap;
 260         }
 261
 262         /* needed ? */
 263         cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
 264         return 1;
 265 }
 266
 267 void __init radix__early_init_devtree(void)
 268 {
 269         int rc;
 270
 271         /*
 272          * Try to find the available page sizes in the device-tree
 273          */
 274         rc = of_scan_flat_dt(radix_dt_scan_page_sizes, NULL);
 275         if (rc != 0)  /* Found */
 276                 goto found;
 277         /*
 278          * let's assume we have page 4k and 64k support
 279          */
 280         mmu_psize_defs[MMU_PAGE_4K].shift = 12;
 281         mmu_psize_defs[MMU_PAGE_4K].ap = 0x0;
 282
 283         mmu_psize_defs[MMU_PAGE_64K].shift = 16;
 284         mmu_psize_defs[MMU_PAGE_64K].ap = 0x5;
 285 found:
 286 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 287         if (mmu_psize_defs[MMU_PAGE_2M].shift) {
 288                 /*
 289                  * map vmemmap using 2M if available
 290                  */
 291                 mmu_vmemmap_psize = MMU_PAGE_2M;
 292         }
 293 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 294         return;
 295 }
 296
 297 void __init radix__early_init_mmu(void)
 298 {
 299         unsigned long lpcr;
 300
 301 #ifdef CONFIG_PPC_64K_PAGES
 302         /* PAGE_SIZE mappings */
 303         mmu_virtual_psize = MMU_PAGE_64K;
 304 #else
 305         mmu_virtual_psize = MMU_PAGE_4K;
 306 #endif
 307
 308 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 309         /* vmemmap mapping */
 310         mmu_vmemmap_psize = mmu_virtual_psize;
 311 #endif
 312         /*
 313          * initialize page table size
 314          */
 315         __pte_index_size = RADIX_PTE_INDEX_SIZE;
 316         __pmd_index_size = RADIX_PMD_INDEX_SIZE;
 317         __pud_index_size = RADIX_PUD_INDEX_SIZE;
 318         __pgd_index_size = RADIX_PGD_INDEX_SIZE;
 319         __pmd_cache_index = RADIX_PMD_INDEX_SIZE;
 320         __pte_table_size = RADIX_PTE_TABLE_SIZE;
 321         __pmd_table_size = RADIX_PMD_TABLE_SIZE;
 322         __pud_table_size = RADIX_PUD_TABLE_SIZE;
 323         __pgd_table_size = RADIX_PGD_TABLE_SIZE;
 324
 325         __pmd_val_bits = RADIX_PMD_VAL_BITS;
 326         __pud_val_bits = RADIX_PUD_VAL_BITS;
 327         __pgd_val_bits = RADIX_PGD_VAL_BITS;
 328
 329         __kernel_virt_start = RADIX_KERN_VIRT_START;
 330         __kernel_virt_size = RADIX_KERN_VIRT_SIZE;
 331         __vmalloc_start = RADIX_VMALLOC_START;
 332         __vmalloc_end = RADIX_VMALLOC_END;
 333         vmemmap = (struct page *)RADIX_VMEMMAP_BASE;
 334         ioremap_bot = IOREMAP_BASE;
 335
 336 #ifdef CONFIG_PCI
 337         pci_io_base = ISA_IO_BASE;
 338 #endif
 339
 340         /*
 341          * For now radix also use the same frag size
 342          */
 343         __pte_frag_nr = H_PTE_FRAG_NR;
 344         __pte_frag_size_shift = H_PTE_FRAG_SIZE_SHIFT;
 345
 346         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 347                 radix_init_native();
 348                 lpcr = mfspr(SPRN_LPCR);
 349                 mtspr(SPRN_LPCR, lpcr | LPCR_UPRT | LPCR_HR);
 350                 radix_init_partition_table();
 351         }
 352
 353         radix_init_pgtable();
 354 }
 355
 356 void radix__early_init_mmu_secondary(void)
 357 {
 358         unsigned long lpcr;
 359         /*
 360          * update partition table control register and UPRT
 361          */
 362         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 363                 lpcr = mfspr(SPRN_LPCR);
 364                 mtspr(SPRN_LPCR, lpcr | LPCR_UPRT | LPCR_HR);
 365
 366                 mtspr(SPRN_PTCR,
 367                       __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
 368         }
 369 }
 370
 371 void radix__setup_initial_memory_limit(phys_addr_t first_memblock_base,
 372                                 phys_addr_t first_memblock_size)
 373 {
 374         /* We don't currently support the first MEMBLOCK not mapping 0
 375          * physical on those processors
 376          */
 377         BUG_ON(first_memblock_base != 0);
 378         /*
 379          * We limit the allocation that depend on ppc64_rma_size
 380          * to first_memblock_size. We also clamp it to 1GB to
 381          * avoid some funky things such as RTAS bugs.
 382          *
 383          * On radix config we really don't have a limitation
 384          * on real mode access. But keeping it as above works
 385          * well enough.
 386          */
 387         ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
 388         /*
 389          * Finally limit subsequent allocations. We really don't want
 390          * to limit the memblock allocations to rma_size. FIXME!! should
 391          * we even limit at all ?
 392          */
 393         memblock_set_current_limit(first_memblock_base + first_memblock_size);
 394 }
 395
 396 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 397 int __meminit radix__vmemmap_create_mapping(unsigned long start,
 398                                       unsigned long page_size,
 399                                       unsigned long phys)
 400 {
 401         /* Create a PTE encoding */
 402         unsigned long flags = _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_KERNEL_RW;
 403
 404         BUG_ON(radix__map_kernel_page(start, phys, __pgprot(flags), page_size));
 405         return 0;
 406 }
 407
 408 #ifdef CONFIG_MEMORY_HOTPLUG
 409 void radix__vmemmap_remove_mapping(unsigned long start, unsigned long page_size)
 410 {
 411         /* FIXME!! intel does more. We should free page tables mapping vmemmap ? */
 412 }
 413 #endif
 414 #endif
 415
 416 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 417
 418 unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
 419                                   pmd_t *pmdp, unsigned long clr,
 420                                   unsigned long set)
 421 {
 422         unsigned long old;
 423
 424 #ifdef CONFIG_DEBUG_VM
 425         WARN_ON(!radix__pmd_trans_huge(*pmdp));
 426         assert_spin_locked(&mm->page_table_lock);
 427 #endif
 428
 429         old = radix__pte_update(mm, addr, (pte_t *)pmdp, clr, set, 1);
 430         trace_hugepage_update(addr, old, clr, set);
 431
 432         return old;
 433 }
 434
 435 pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 436                         pmd_t *pmdp)
 437
 438 {
 439         pmd_t pmd;
 440
 441         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 442         VM_BUG_ON(radix__pmd_trans_huge(*pmdp));
 443         /*
 444          * khugepaged calls this for normal pmd
 445          */
 446         pmd = *pmdp;
 447         pmd_clear(pmdp);
 448         /*FIXME!!  Verify whether we need this kick below */
 449         kick_all_cpus_sync();
 450         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 451         return pmd;
 452 }
 453
 454 /*
 455  * For us pgtable_t is pte_t *. Inorder to save the deposisted
 456  * page table, we consider the allocated page table as a list
 457  * head. On withdraw we need to make sure we zero out the used
 458  * list_head memory area.
 459  */
 460 void radix__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 461                                  pgtable_t pgtable)
 462 {
 463         struct list_head *lh = (struct list_head *) pgtable;
 464
 465         assert_spin_locked(pmd_lockptr(mm, pmdp));
 466
 467         /* FIFO */
 468         if (!pmd_huge_pte(mm, pmdp))
 469                 INIT_LIST_HEAD(lh);
 470         else
 471                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 472         pmd_huge_pte(mm, pmdp) = pgtable;
 473 }
 474
 475 pgtable_t radix__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 476 {
 477         pte_t *ptep;
 478         pgtable_t pgtable;
 479         struct list_head *lh;
 480
 481         assert_spin_locked(pmd_lockptr(mm, pmdp));
 482
 483         /* FIFO */
 484         pgtable = pmd_huge_pte(mm, pmdp);
 485         lh = (struct list_head *) pgtable;
 486         if (list_empty(lh))
 487                 pmd_huge_pte(mm, pmdp) = NULL;
 488         else {
 489                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 490                 list_del(lh);
 491         }
 492         ptep = (pte_t *) pgtable;
 493         *ptep = __pte(0);
 494         ptep++;
 495         *ptep = __pte(0);
 496         return pgtable;
 497 }
 498
 499
 500 pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm,
 501                                unsigned long addr, pmd_t *pmdp)
 502 {
 503         pmd_t old_pmd;
 504         unsigned long old;
 505
 506         old = radix__pmd_hugepage_update(mm, addr, pmdp, ~0UL, 0);
 507         old_pmd = __pmd(old);
 508         /*
 509          * Serialize against find_linux_pte_or_hugepte which does lock-less
 510          * lookup in page tables with local interrupts disabled. For huge pages
 511          * it casts pmd_t to pte_t. Since format of pte_t is different from
 512          * pmd_t we want to prevent transit from pmd pointing to page table
 513          * to pmd pointing to huge page (and back) while interrupts are disabled.
 514          * We clear pmd to possibly replace it with page table pointer in
 515          * different code paths. So make sure we wait for the parallel
 516          * find_linux_pte_or_hugepage to finish.
 517          */
 518         kick_all_cpus_sync();
 519         return old_pmd;
 520 }
 521
 522 int radix__has_transparent_hugepage(void)
 523 {
 524         /* For radix 2M at PMD level means thp */
 525         if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
 526                 return 1;
 527         return 0;
 528 }
 529 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */