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_update_partition_table(u64 patb1)
  25 {
  26         partition_tb->patb1 = cpu_to_be64(patb1);
  27         return 0;
  28 }
  29
  30 static __ref void *early_alloc_pgtable(unsigned long size)
  31 {
  32         void *pt;
  33
  34         pt = __va(memblock_alloc_base(size, size, MEMBLOCK_ALLOC_ANYWHERE));
  35         memset(pt, 0, size);
  36
  37         return pt;
  38 }
  39
  40 int radix__map_kernel_page(unsigned long ea, unsigned long pa,
  41                           pgprot_t flags,
  42                           unsigned int map_page_size)
  43 {
  44         pgd_t *pgdp;
  45         pud_t *pudp;
  46         pmd_t *pmdp;
  47         pte_t *ptep;
  48         /*
  49          * Make sure task size is correct as per the max adddr
  50          */
  51         BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);
  52         if (slab_is_available()) {
  53                 pgdp = pgd_offset_k(ea);
  54                 pudp = pud_alloc(&init_mm, pgdp, ea);
  55                 if (!pudp)
  56                         return -ENOMEM;
  57                 if (map_page_size == PUD_SIZE) {
  58                         ptep = (pte_t *)pudp;
  59                         goto set_the_pte;
  60                 }
  61                 pmdp = pmd_alloc(&init_mm, pudp, ea);
  62                 if (!pmdp)
  63                         return -ENOMEM;
  64                 if (map_page_size == PMD_SIZE) {
  65                         ptep = (pte_t *)pudp;
  66                         goto set_the_pte;
  67                 }
  68                 ptep = pte_alloc_kernel(pmdp, ea);
  69                 if (!ptep)
  70                         return -ENOMEM;
  71         } else {
  72                 pgdp = pgd_offset_k(ea);
  73                 if (pgd_none(*pgdp)) {
  74                         pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
  75                         BUG_ON(pudp == NULL);
  76                         pgd_populate(&init_mm, pgdp, pudp);
  77                 }
  78                 pudp = pud_offset(pgdp, ea);
  79                 if (map_page_size == PUD_SIZE) {
  80                         ptep = (pte_t *)pudp;
  81                         goto set_the_pte;
  82                 }
  83                 if (pud_none(*pudp)) {
  84                         pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
  85                         BUG_ON(pmdp == NULL);
  86                         pud_populate(&init_mm, pudp, pmdp);
  87                 }
  88                 pmdp = pmd_offset(pudp, ea);
  89                 if (map_page_size == PMD_SIZE) {
  90                         ptep = (pte_t *)pudp;
  91                         goto set_the_pte;
  92                 }
  93                 if (!pmd_present(*pmdp)) {
  94                         ptep = early_alloc_pgtable(PAGE_SIZE);
  95                         BUG_ON(ptep == NULL);
  96                         pmd_populate_kernel(&init_mm, pmdp, ptep);
  97                 }
  98                 ptep = pte_offset_kernel(pmdp, ea);
  99         }
 100
 101 set_the_pte:
 102         set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, flags));
 103         smp_wmb();
 104         return 0;
 105 }
 106
 107 static void __init radix_init_pgtable(void)
 108 {
 109         int loop_count;
 110         u64 base, end, start_addr;
 111         unsigned long rts_field;
 112         struct memblock_region *reg;
 113         unsigned long linear_page_size;
 114
 115         /* We don't support slb for radix */
 116         mmu_slb_size = 0;
 117         /*
 118          * Create the linear mapping, using standard page size for now
 119          */
 120         loop_count = 0;
 121         for_each_memblock(memory, reg) {
 122
 123                 start_addr = reg->base;
 124
 125 redo:
 126                 if (loop_count < 1 && mmu_psize_defs[MMU_PAGE_1G].shift)
 127                         linear_page_size = PUD_SIZE;
 128                 else if (loop_count < 2 && mmu_psize_defs[MMU_PAGE_2M].shift)
 129                         linear_page_size = PMD_SIZE;
 130                 else
 131                         linear_page_size = PAGE_SIZE;
 132
 133                 base = _ALIGN_UP(start_addr, linear_page_size);
 134                 end = _ALIGN_DOWN(reg->base + reg->size, linear_page_size);
 135
 136                 pr_info("Mapping range 0x%lx - 0x%lx with 0x%lx\n",
 137                         (unsigned long)base, (unsigned long)end,
 138                         linear_page_size);
 139
 140                 while (base < end) {
 141                         radix__map_kernel_page((unsigned long)__va(base),
 142                                               base, PAGE_KERNEL_X,
 143                                               linear_page_size);
 144                         base += linear_page_size;
 145                 }
 146                 /*
 147                  * map the rest using lower page size
 148                  */
 149                 if (end < reg->base + reg->size) {
 150                         start_addr = end;
 151                         loop_count++;
 152                         goto redo;
 153                 }
 154         }
 155         /*
 156          * Allocate Partition table and process table for the
 157          * host.
 158          */
 159         BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 23), "Process table size too large.");
 160         process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
 161         /*
 162          * Fill in the process table.
 163          * we support 52 bits, hence 52-28 = 24, 11000
 164          */
 165         rts_field = 3ull << PPC_BITLSHIFT(2);
 166         process_tb->prtb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) | RADIX_PGD_INDEX_SIZE);
 167         /*
 168          * Fill in the partition table. We are suppose to use effective address
 169          * of process table here. But our linear mapping also enable us to use
 170          * physical address here.
 171          */
 172         ppc_md.update_partition_table(__pa(process_tb) | (PRTB_SIZE_SHIFT - 12) | PATB_GR);
 173         pr_info("Process table %p and radix root for kernel: %p\n", process_tb, init_mm.pgd);
 174 }
 175
 176 static void __init radix_init_partition_table(void)
 177 {
 178         unsigned long rts_field;
 179         /*
 180          * we support 52 bits, hence 52-28 = 24, 11000
 181          */
 182         rts_field = 3ull << PPC_BITLSHIFT(2);
 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         printk("Partition table %p\n", partition_tb);
 189
 190         memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
 191         /*
 192          * update partition table control register,
 193          * 64 K size.
 194          */
 195         mtspr(SPRN_PTCR, __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
 196 }
 197
 198 void __init radix_init_native(void)
 199 {
 200         ppc_md.update_partition_table = native_update_partition_table;
 201 }
 202
 203 static int __init get_idx_from_shift(unsigned int shift)
 204 {
 205         int idx = -1;
 206
 207         switch (shift) {
 208         case 0xc:
 209                 idx = MMU_PAGE_4K;
 210                 break;
 211         case 0x10:
 212                 idx = MMU_PAGE_64K;
 213                 break;
 214         case 0x15:
 215                 idx = MMU_PAGE_2M;
 216                 break;
 217         case 0x1e:
 218                 idx = MMU_PAGE_1G;
 219                 break;
 220         }
 221         return idx;
 222 }
 223
 224 static int __init radix_dt_scan_page_sizes(unsigned long node,
 225                                            const char *uname, int depth,
 226                                            void *data)
 227 {
 228         int size = 0;
 229         int shift, idx;
 230         unsigned int ap;
 231         const __be32 *prop;
 232         const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 233
 234         /* We are scanning "cpu" nodes only */
 235         if (type == NULL || strcmp(type, "cpu") != 0)
 236                 return 0;
 237
 238         prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
 239         if (!prop)
 240                 return 0;
 241
 242         pr_info("Page sizes from device-tree:\n");
 243         for (; size >= 4; size -= 4, ++prop) {
 244
 245                 struct mmu_psize_def *def;
 246
 247                 /* top 3 bit is AP encoding */
 248                 shift = be32_to_cpu(prop[0]) & ~(0xe << 28);
 249                 ap = be32_to_cpu(prop[0]) >> 29;
 250                 pr_info("Page size sift = %d AP=0x%x\n", shift, ap);
 251
 252                 idx = get_idx_from_shift(shift);
 253                 if (idx < 0)
 254                         continue;
 255
 256                 def = &mmu_psize_defs[idx];
 257                 def->shift = shift;
 258                 def->ap  = ap;
 259         }
 260
 261         /* needed ? */
 262         cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
 263         return 1;
 264 }
 265
 266 static void __init radix_init_page_sizes(void)
 267 {
 268         int rc;
 269
 270         /*
 271          * Try to find the available page sizes in the device-tree
 272          */
 273         rc = of_scan_flat_dt(radix_dt_scan_page_sizes, NULL);
 274         if (rc != 0)  /* Found */
 275                 goto found;
 276         /*
 277          * let's assume we have page 4k and 64k support
 278          */
 279         mmu_psize_defs[MMU_PAGE_4K].shift = 12;
 280         mmu_psize_defs[MMU_PAGE_4K].ap = 0x0;
 281
 282         mmu_psize_defs[MMU_PAGE_64K].shift = 16;
 283         mmu_psize_defs[MMU_PAGE_64K].ap = 0x5;
 284 found:
 285 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 286         if (mmu_psize_defs[MMU_PAGE_2M].shift) {
 287                 /*
 288                  * map vmemmap using 2M if available
 289                  */
 290                 mmu_vmemmap_psize = MMU_PAGE_2M;
 291         }
 292 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 293         return;
 294 }
 295
 296 void __init radix__early_init_mmu(void)
 297 {
 298         unsigned long lpcr;
 299
 300 #ifdef CONFIG_PPC_64K_PAGES
 301         /* PAGE_SIZE mappings */
 302         mmu_virtual_psize = MMU_PAGE_64K;
 303 #else
 304         mmu_virtual_psize = MMU_PAGE_4K;
 305 #endif
 306
 307 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 308         /* vmemmap mapping */
 309         mmu_vmemmap_psize = mmu_virtual_psize;
 310 #endif
 311         /*
 312          * initialize page table size
 313          */
 314         __pte_index_size = RADIX_PTE_INDEX_SIZE;
 315         __pmd_index_size = RADIX_PMD_INDEX_SIZE;
 316         __pud_index_size = RADIX_PUD_INDEX_SIZE;
 317         __pgd_index_size = RADIX_PGD_INDEX_SIZE;
 318         __pmd_cache_index = RADIX_PMD_INDEX_SIZE;
 319         __pte_table_size = RADIX_PTE_TABLE_SIZE;
 320         __pmd_table_size = RADIX_PMD_TABLE_SIZE;
 321         __pud_table_size = RADIX_PUD_TABLE_SIZE;
 322         __pgd_table_size = RADIX_PGD_TABLE_SIZE;
 323
 324         __pmd_val_bits = RADIX_PMD_VAL_BITS;
 325         __pud_val_bits = RADIX_PUD_VAL_BITS;
 326         __pgd_val_bits = RADIX_PGD_VAL_BITS;
 327
 328         __kernel_virt_start = RADIX_KERN_VIRT_START;
 329         __kernel_virt_size = RADIX_KERN_VIRT_SIZE;
 330         __vmalloc_start = RADIX_VMALLOC_START;
 331         __vmalloc_end = RADIX_VMALLOC_END;
 332         vmemmap = (struct page *)RADIX_VMEMMAP_BASE;
 333         ioremap_bot = IOREMAP_BASE;
 334         /*
 335          * For now radix also use the same frag size
 336          */
 337         __pte_frag_nr = H_PTE_FRAG_NR;
 338         __pte_frag_size_shift = H_PTE_FRAG_SIZE_SHIFT;
 339
 340         radix_init_page_sizes();
 341         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 342                 lpcr = mfspr(SPRN_LPCR);
 343                 mtspr(SPRN_LPCR, lpcr | LPCR_UPRT);
 344                 radix_init_partition_table();
 345         }
 346
 347         radix_init_pgtable();
 348 }
 349
 350 void radix__early_init_mmu_secondary(void)
 351 {
 352         unsigned long lpcr;
 353         /*
 354          * update partition table control register and UPRT
 355          */
 356         if (!firmware_has_feature(FW_FEATURE_LPAR)) {
 357                 lpcr = mfspr(SPRN_LPCR);
 358                 mtspr(SPRN_LPCR, lpcr | LPCR_UPRT);
 359
 360                 mtspr(SPRN_PTCR,
 361                       __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
 362         }
 363 }
 364
 365 void radix__setup_initial_memory_limit(phys_addr_t first_memblock_base,
 366                                 phys_addr_t first_memblock_size)
 367 {
 368         /* We don't currently support the first MEMBLOCK not mapping 0
 369          * physical on those processors
 370          */
 371         BUG_ON(first_memblock_base != 0);
 372         /*
 373          * We limit the allocation that depend on ppc64_rma_size
 374          * to first_memblock_size. We also clamp it to 1GB to
 375          * avoid some funky things such as RTAS bugs.
 376          *
 377          * On radix config we really don't have a limitation
 378          * on real mode access. But keeping it as above works
 379          * well enough.
 380          */
 381         ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
 382         /*
 383          * Finally limit subsequent allocations. We really don't want
 384          * to limit the memblock allocations to rma_size. FIXME!! should
 385          * we even limit at all ?
 386          */
 387         memblock_set_current_limit(first_memblock_base + first_memblock_size);
 388 }
 389
 390 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 391 int __meminit radix__vmemmap_create_mapping(unsigned long start,
 392                                       unsigned long page_size,
 393                                       unsigned long phys)
 394 {
 395         /* Create a PTE encoding */
 396         unsigned long flags = _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_KERNEL_RW;
 397
 398         BUG_ON(radix__map_kernel_page(start, phys, __pgprot(flags), page_size));
 399         return 0;
 400 }
 401
 402 #ifdef CONFIG_MEMORY_HOTPLUG
 403 void radix__vmemmap_remove_mapping(unsigned long start, unsigned long page_size)
 404 {
 405         /* FIXME!! intel does more. We should free page tables mapping vmemmap ? */
 406 }
 407 #endif
 408 #endif
 409
 410 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 411
 412 unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
 413                                   pmd_t *pmdp, unsigned long clr,
 414                                   unsigned long set)
 415 {
 416         unsigned long old;
 417
 418 #ifdef CONFIG_DEBUG_VM
 419         WARN_ON(!radix__pmd_trans_huge(*pmdp));
 420         assert_spin_locked(&mm->page_table_lock);
 421 #endif
 422
 423         old = radix__pte_update(mm, addr, (pte_t *)pmdp, clr, set, 1);
 424         trace_hugepage_update(addr, old, clr, set);
 425
 426         return old;
 427 }
 428
 429 pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 430                         pmd_t *pmdp)
 431
 432 {
 433         pmd_t pmd;
 434
 435         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 436         VM_BUG_ON(radix__pmd_trans_huge(*pmdp));
 437         /*
 438          * khugepaged calls this for normal pmd
 439          */
 440         pmd = *pmdp;
 441         pmd_clear(pmdp);
 442         /*FIXME!!  Verify whether we need this kick below */
 443         kick_all_cpus_sync();
 444         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 445         return pmd;
 446 }
 447
 448 /*
 449  * For us pgtable_t is pte_t *. Inorder to save the deposisted
 450  * page table, we consider the allocated page table as a list
 451  * head. On withdraw we need to make sure we zero out the used
 452  * list_head memory area.
 453  */
 454 void radix__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 455                                  pgtable_t pgtable)
 456 {
 457         struct list_head *lh = (struct list_head *) pgtable;
 458
 459         assert_spin_locked(pmd_lockptr(mm, pmdp));
 460
 461         /* FIFO */
 462         if (!pmd_huge_pte(mm, pmdp))
 463                 INIT_LIST_HEAD(lh);
 464         else
 465                 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
 466         pmd_huge_pte(mm, pmdp) = pgtable;
 467 }
 468
 469 pgtable_t radix__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 470 {
 471         pte_t *ptep;
 472         pgtable_t pgtable;
 473         struct list_head *lh;
 474
 475         assert_spin_locked(pmd_lockptr(mm, pmdp));
 476
 477         /* FIFO */
 478         pgtable = pmd_huge_pte(mm, pmdp);
 479         lh = (struct list_head *) pgtable;
 480         if (list_empty(lh))
 481                 pmd_huge_pte(mm, pmdp) = NULL;
 482         else {
 483                 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
 484                 list_del(lh);
 485         }
 486         ptep = (pte_t *) pgtable;
 487         *ptep = __pte(0);
 488         ptep++;
 489         *ptep = __pte(0);
 490         return pgtable;
 491 }
 492
 493
 494 pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm,
 495                                unsigned long addr, pmd_t *pmdp)
 496 {
 497         pmd_t old_pmd;
 498         unsigned long old;
 499
 500         old = radix__pmd_hugepage_update(mm, addr, pmdp, ~0UL, 0);
 501         old_pmd = __pmd(old);
 502         /*
 503          * Serialize against find_linux_pte_or_hugepte which does lock-less
 504          * lookup in page tables with local interrupts disabled. For huge pages
 505          * it casts pmd_t to pte_t. Since format of pte_t is different from
 506          * pmd_t we want to prevent transit from pmd pointing to page table
 507          * to pmd pointing to huge page (and back) while interrupts are disabled.
 508          * We clear pmd to possibly replace it with page table pointer in
 509          * different code paths. So make sure we wait for the parallel
 510          * find_linux_pte_or_hugepage to finish.
 511          */
 512         kick_all_cpus_sync();
 513         return old_pmd;
 514 }
 515
 516 int radix__has_transparent_hugepage(void)
 517 {
 518         /* For radix 2M at PMD level means thp */
 519         if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
 520                 return 1;
 521         return 0;
 522 }
 523 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */