arch/riscv/mm/init.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Regents of the University of California
   4  * Copyright (C) 2019 Western Digital Corporation or its affiliates.
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/mm.h>
   9 #include <linux/memblock.h>
  10 #include <linux/initrd.h>
  11 #include <linux/swap.h>
  12 #include <linux/sizes.h>
  13 #include <linux/of_fdt.h>
  14 #include <linux/libfdt.h>
  15
  16 #include <asm/fixmap.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/sections.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/io.h>
  21
  22 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
  23                                                         __page_aligned_bss;
  24 EXPORT_SYMBOL(empty_zero_page);
  25
  26 extern char _start[];
  27
  28 static void __init zone_sizes_init(void)
  29 {
  30         unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
  31
  32 #ifdef CONFIG_ZONE_DMA32
  33         max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
  34                         (unsigned long) PFN_PHYS(max_low_pfn)));
  35 #endif
  36         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
  37
  38         free_area_init_nodes(max_zone_pfns);
  39 }
  40
  41 void setup_zero_page(void)
  42 {
  43         memset((void *)empty_zero_page, 0, PAGE_SIZE);
  44 }
  45
  46 void __init mem_init(void)
  47 {
  48 #ifdef CONFIG_FLATMEM
  49         BUG_ON(!mem_map);
  50 #endif /* CONFIG_FLATMEM */
  51
  52         high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
  53         memblock_free_all();
  54
  55         mem_init_print_info(NULL);
  56 }
  57
  58 #ifdef CONFIG_BLK_DEV_INITRD
  59 static void __init setup_initrd(void)
  60 {
  61         unsigned long size;
  62
  63         if (initrd_start >= initrd_end) {
  64                 pr_info("initrd not found or empty");
  65                 goto disable;
  66         }
  67         if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
  68                 pr_err("initrd extends beyond end of memory");
  69                 goto disable;
  70         }
  71
  72         size = initrd_end - initrd_start;
  73         memblock_reserve(__pa(initrd_start), size);
  74         initrd_below_start_ok = 1;
  75
  76         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
  77                 (void *)(initrd_start), size);
  78         return;
  79 disable:
  80         pr_cont(" - disabling initrd\n");
  81         initrd_start = 0;
  82         initrd_end = 0;
  83 }
  84 #endif /* CONFIG_BLK_DEV_INITRD */
  85
  86 static phys_addr_t dtb_early_pa __initdata;
  87
  88 void __init setup_bootmem(void)
  89 {
  90         struct memblock_region *reg;
  91         phys_addr_t mem_size = 0;
  92         phys_addr_t vmlinux_end = __pa(&_end);
  93         phys_addr_t vmlinux_start = __pa(&_start);
  94
  95         /* Find the memory region containing the kernel */
  96         for_each_memblock(memory, reg) {
  97                 phys_addr_t end = reg->base + reg->size;
  98
  99                 if (reg->base <= vmlinux_end && vmlinux_end <= end) {
 100                         mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
 101
 102                         /*
 103                          * Remove memblock from the end of usable area to the
 104                          * end of region
 105                          */
 106                         if (reg->base + mem_size < end)
 107                                 memblock_remove(reg->base + mem_size,
 108                                                 end - reg->base - mem_size);
 109                 }
 110         }
 111         BUG_ON(mem_size == 0);
 112
 113         /* Reserve from the start of the kernel to the end of the kernel */
 114         memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 115
 116         set_max_mapnr(PFN_DOWN(mem_size));
 117         max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
 118
 119 #ifdef CONFIG_BLK_DEV_INITRD
 120         setup_initrd();
 121 #endif /* CONFIG_BLK_DEV_INITRD */
 122
 123         /*
 124          * Avoid using early_init_fdt_reserve_self() since __pa() does
 125          * not work for DTB pointers that are fixmap addresses
 126          */
 127         memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
 128
 129         early_init_fdt_scan_reserved_mem();
 130         memblock_allow_resize();
 131         memblock_dump_all();
 132
 133         for_each_memblock(memory, reg) {
 134                 unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 135                 unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
 136
 137                 memblock_set_node(PFN_PHYS(start_pfn),
 138                                   PFN_PHYS(end_pfn - start_pfn),
 139                                   &memblock.memory, 0);
 140         }
 141 }
 142
 143 unsigned long va_pa_offset;
 144 EXPORT_SYMBOL(va_pa_offset);
 145 unsigned long pfn_base;
 146 EXPORT_SYMBOL(pfn_base);
 147
 148 void *dtb_early_va;
 149 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 150 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 151 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
 152 static bool mmu_enabled;
 153
 154 #define MAX_EARLY_MAPPING_SIZE  SZ_128M
 155
 156 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 157
 158 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 159 {
 160         unsigned long addr = __fix_to_virt(idx);
 161         pte_t *ptep;
 162
 163         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 164
 165         ptep = &fixmap_pte[pte_index(addr)];
 166
 167         if (pgprot_val(prot)) {
 168                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 169         } else {
 170                 pte_clear(&init_mm, addr, ptep);
 171                 local_flush_tlb_page(addr);
 172         }
 173 }
 174
 175 static pte_t *__init get_pte_virt(phys_addr_t pa)
 176 {
 177         if (mmu_enabled) {
 178                 clear_fixmap(FIX_PTE);
 179                 return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
 180         } else {
 181                 return (pte_t *)((uintptr_t)pa);
 182         }
 183 }
 184
 185 static phys_addr_t __init alloc_pte(uintptr_t va)
 186 {
 187         /*
 188          * We only create PMD or PGD early mappings so we
 189          * should never reach here with MMU disabled.
 190          */
 191         BUG_ON(!mmu_enabled);
 192
 193         return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 194 }
 195
 196 static void __init create_pte_mapping(pte_t *ptep,
 197                                       uintptr_t va, phys_addr_t pa,
 198                                       phys_addr_t sz, pgprot_t prot)
 199 {
 200         uintptr_t pte_index = pte_index(va);
 201
 202         BUG_ON(sz != PAGE_SIZE);
 203
 204         if (pte_none(ptep[pte_index]))
 205                 ptep[pte_index] = pfn_pte(PFN_DOWN(pa), prot);
 206 }
 207
 208 #ifndef __PAGETABLE_PMD_FOLDED
 209
 210 pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
 211 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 212
 213 #if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
 214 #define NUM_EARLY_PMDS          1UL
 215 #else
 216 #define NUM_EARLY_PMDS          (1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
 217 #endif
 218 pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
 219
 220 static pmd_t *__init get_pmd_virt(phys_addr_t pa)
 221 {
 222         if (mmu_enabled) {
 223                 clear_fixmap(FIX_PMD);
 224                 return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
 225         } else {
 226                 return (pmd_t *)((uintptr_t)pa);
 227         }
 228 }
 229
 230 static phys_addr_t __init alloc_pmd(uintptr_t va)
 231 {
 232         uintptr_t pmd_num;
 233
 234         if (mmu_enabled)
 235                 return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 236
 237         pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
 238         BUG_ON(pmd_num >= NUM_EARLY_PMDS);
 239         return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
 240 }
 241
 242 static void __init create_pmd_mapping(pmd_t *pmdp,
 243                                       uintptr_t va, phys_addr_t pa,
 244                                       phys_addr_t sz, pgprot_t prot)
 245 {
 246         pte_t *ptep;
 247         phys_addr_t pte_phys;
 248         uintptr_t pmd_index = pmd_index(va);
 249
 250         if (sz == PMD_SIZE) {
 251                 if (pmd_none(pmdp[pmd_index]))
 252                         pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pa), prot);
 253                 return;
 254         }
 255
 256         if (pmd_none(pmdp[pmd_index])) {
 257                 pte_phys = alloc_pte(va);
 258                 pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
 259                 ptep = get_pte_virt(pte_phys);
 260                 memset(ptep, 0, PAGE_SIZE);
 261         } else {
 262                 pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_index]));
 263                 ptep = get_pte_virt(pte_phys);
 264         }
 265
 266         create_pte_mapping(ptep, va, pa, sz, prot);
 267 }
 268
 269 #define pgd_next_t              pmd_t
 270 #define alloc_pgd_next(__va)    alloc_pmd(__va)
 271 #define get_pgd_next_virt(__pa) get_pmd_virt(__pa)
 272 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 273         create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
 274 #define PTE_PARENT_SIZE         PMD_SIZE
 275 #define fixmap_pgd_next         fixmap_pmd
 276 #else
 277 #define pgd_next_t              pte_t
 278 #define alloc_pgd_next(__va)    alloc_pte(__va)
 279 #define get_pgd_next_virt(__pa) get_pte_virt(__pa)
 280 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 281         create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
 282 #define PTE_PARENT_SIZE         PGDIR_SIZE
 283 #define fixmap_pgd_next         fixmap_pte
 284 #endif
 285
 286 static void __init create_pgd_mapping(pgd_t *pgdp,
 287                                       uintptr_t va, phys_addr_t pa,
 288                                       phys_addr_t sz, pgprot_t prot)
 289 {
 290         pgd_next_t *nextp;
 291         phys_addr_t next_phys;
 292         uintptr_t pgd_index = pgd_index(va);
 293
 294         if (sz == PGDIR_SIZE) {
 295                 if (pgd_val(pgdp[pgd_index]) == 0)
 296                         pgdp[pgd_index] = pfn_pgd(PFN_DOWN(pa), prot);
 297                 return;
 298         }
 299
 300         if (pgd_val(pgdp[pgd_index]) == 0) {
 301                 next_phys = alloc_pgd_next(va);
 302                 pgdp[pgd_index] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
 303                 nextp = get_pgd_next_virt(next_phys);
 304                 memset(nextp, 0, PAGE_SIZE);
 305         } else {
 306                 next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_index]));
 307                 nextp = get_pgd_next_virt(next_phys);
 308         }
 309
 310         create_pgd_next_mapping(nextp, va, pa, sz, prot);
 311 }
 312
 313 static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
 314 {
 315         uintptr_t map_size = PAGE_SIZE;
 316
 317         /* Upgrade to PMD/PGDIR mappings whenever possible */
 318         if (!(base & (PTE_PARENT_SIZE - 1)) &&
 319             !(size & (PTE_PARENT_SIZE - 1)))
 320                 map_size = PTE_PARENT_SIZE;
 321
 322         return map_size;
 323 }
 324
 325 /*
 326  * setup_vm() is called from head.S with MMU-off.
 327  *
 328  * Following requirements should be honoured for setup_vm() to work
 329  * correctly:
 330  * 1) It should use PC-relative addressing for accessing kernel symbols.
 331  *    To achieve this we always use GCC cmodel=medany.
 332  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 333  *    so disable compiler instrumentation when FTRACE is enabled.
 334  *
 335  * Currently, the above requirements are honoured by using custom CFLAGS
 336  * for init.o in mm/Makefile.
 337  */
 338
 339 #ifndef __riscv_cmodel_medany
 340 #error "setup_vm() is called from head.S before relocate so it should "
 341         "not use absolute addressing."
 342 #endif
 343
 344 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 345 {
 346         uintptr_t va, end_va;
 347         uintptr_t load_pa = (uintptr_t)(&_start);
 348         uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
 349         uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
 350
 351         va_pa_offset = PAGE_OFFSET - load_pa;
 352         pfn_base = PFN_DOWN(load_pa);
 353
 354         /*
 355          * Enforce boot alignment requirements of RV32 and
 356          * RV64 by only allowing PMD or PGD mappings.
 357          */
 358         BUG_ON(map_size == PAGE_SIZE);
 359
 360         /* Sanity check alignment and size */
 361         BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 362         BUG_ON((load_pa % map_size) != 0);
 363         BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
 364
 365         /* Setup early PGD for fixmap */
 366         create_pgd_mapping(early_pg_dir, FIXADDR_START,
 367                            (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
 368
 369 #ifndef __PAGETABLE_PMD_FOLDED
 370         /* Setup fixmap PMD */
 371         create_pmd_mapping(fixmap_pmd, FIXADDR_START,
 372                            (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
 373         /* Setup trampoline PGD and PMD */
 374         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 375                            (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
 376         create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
 377                            load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
 378 #else
 379         /* Setup trampoline PGD */
 380         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 381                            load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
 382 #endif
 383
 384         /*
 385          * Setup early PGD covering entire kernel which will allows
 386          * us to reach paging_init(). We map all memory banks later
 387          * in setup_vm_final() below.
 388          */
 389         end_va = PAGE_OFFSET + load_sz;
 390         for (va = PAGE_OFFSET; va < end_va; va += map_size)
 391                 create_pgd_mapping(early_pg_dir, va,
 392                                    load_pa + (va - PAGE_OFFSET),
 393                                    map_size, PAGE_KERNEL_EXEC);
 394
 395         /* Create fixed mapping for early FDT parsing */
 396         end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE;
 397         for (va = __fix_to_virt(FIX_FDT); va < end_va; va += PAGE_SIZE)
 398                 create_pte_mapping(fixmap_pte, va,
 399                                    dtb_pa + (va - __fix_to_virt(FIX_FDT)),
 400                                    PAGE_SIZE, PAGE_KERNEL);
 401
 402         /* Save pointer to DTB for early FDT parsing */
 403         dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK);
 404         /* Save physical address for memblock reservation */
 405         dtb_early_pa = dtb_pa;
 406 }
 407
 408 static void __init setup_vm_final(void)
 409 {
 410         uintptr_t va, map_size;
 411         phys_addr_t pa, start, end;
 412         struct memblock_region *reg;
 413
 414         /* Set mmu_enabled flag */
 415         mmu_enabled = true;
 416
 417         /* Setup swapper PGD for fixmap */
 418         create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
 419                            __pa(fixmap_pgd_next),
 420                            PGDIR_SIZE, PAGE_TABLE);
 421
 422         /* Map all memory banks */
 423         for_each_memblock(memory, reg) {
 424                 start = reg->base;
 425                 end = start + reg->size;
 426
 427                 if (start >= end)
 428                         break;
 429                 if (memblock_is_nomap(reg))
 430                         continue;
 431                 if (start <= __pa(PAGE_OFFSET) &&
 432                     __pa(PAGE_OFFSET) < end)
 433                         start = __pa(PAGE_OFFSET);
 434
 435                 map_size = best_map_size(start, end - start);
 436                 for (pa = start; pa < end; pa += map_size) {
 437                         va = (uintptr_t)__va(pa);
 438                         create_pgd_mapping(swapper_pg_dir, va, pa,
 439                                            map_size, PAGE_KERNEL_EXEC);
 440                 }
 441         }
 442
 443         /* Clear fixmap PTE and PMD mappings */
 444         clear_fixmap(FIX_PTE);
 445         clear_fixmap(FIX_PMD);
 446
 447         /* Move to swapper page table */
 448         csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | SATP_MODE);
 449         local_flush_tlb_all();
 450 }
 451
 452 void __init paging_init(void)
 453 {
 454         setup_vm_final();
 455         memblocks_present();
 456         sparse_init();
 457         setup_zero_page();
 458         zone_sizes_init();
 459 }
 460
 461 #ifdef CONFIG_SPARSEMEM
 462 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 463                                struct vmem_altmap *altmap)
 464 {
 465         return vmemmap_populate_basepages(start, end, node);
 466 }
 467 #endif