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