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 #include <linux/set_memory.h>
  16
  17 #include <asm/fixmap.h>
  18 #include <asm/tlbflush.h>
  19 #include <asm/sections.h>
  20 #include <asm/soc.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/io.h>
  23 #include <asm/ptdump.h>
  24
  25 #include "../kernel/head.h"
  26
  27 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
  28                                                         __page_aligned_bss;
  29 EXPORT_SYMBOL(empty_zero_page);
  30
  31 extern char _start[];
  32 void *dtb_early_va;
  33
  34 static void __init zone_sizes_init(void)
  35 {
  36         unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
  37
  38 #ifdef CONFIG_ZONE_DMA32
  39         max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
  40                         (unsigned long) PFN_PHYS(max_low_pfn)));
  41 #endif
  42         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
  43
  44         free_area_init(max_zone_pfns);
  45 }
  46
  47 static void setup_zero_page(void)
  48 {
  49         memset((void *)empty_zero_page, 0, PAGE_SIZE);
  50 }
  51
  52 #if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)
  53 static inline void print_mlk(char *name, unsigned long b, unsigned long t)
  54 {
  55         pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld kB)\n", name, b, t,
  56                   (((t) - (b)) >> 10));
  57 }
  58
  59 static inline void print_mlm(char *name, unsigned long b, unsigned long t)
  60 {
  61         pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld MB)\n", name, b, t,
  62                   (((t) - (b)) >> 20));
  63 }
  64
  65 static void print_vm_layout(void)
  66 {
  67         pr_notice("Virtual kernel memory layout:\n");
  68         print_mlk("fixmap", (unsigned long)FIXADDR_START,
  69                   (unsigned long)FIXADDR_TOP);
  70         print_mlm("pci io", (unsigned long)PCI_IO_START,
  71                   (unsigned long)PCI_IO_END);
  72         print_mlm("vmemmap", (unsigned long)VMEMMAP_START,
  73                   (unsigned long)VMEMMAP_END);
  74         print_mlm("vmalloc", (unsigned long)VMALLOC_START,
  75                   (unsigned long)VMALLOC_END);
  76         print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
  77                   (unsigned long)high_memory);
  78 }
  79 #else
  80 static void print_vm_layout(void) { }
  81 #endif /* CONFIG_DEBUG_VM */
  82
  83 void __init mem_init(void)
  84 {
  85 #ifdef CONFIG_FLATMEM
  86         BUG_ON(!mem_map);
  87 #endif /* CONFIG_FLATMEM */
  88
  89         high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
  90         memblock_free_all();
  91
  92         mem_init_print_info(NULL);
  93         print_vm_layout();
  94 }
  95
  96 #ifdef CONFIG_BLK_DEV_INITRD
  97 static void __init setup_initrd(void)
  98 {
  99         unsigned long size;
 100
 101         if (initrd_start >= initrd_end) {
 102                 pr_info("initrd not found or empty");
 103                 goto disable;
 104         }
 105         if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) {
 106                 pr_err("initrd extends beyond end of memory");
 107                 goto disable;
 108         }
 109
 110         size = initrd_end - initrd_start;
 111         memblock_reserve(__pa_symbol(initrd_start), size);
 112         initrd_below_start_ok = 1;
 113
 114         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
 115                 (void *)(initrd_start), size);
 116         return;
 117 disable:
 118         pr_cont(" - disabling initrd\n");
 119         initrd_start = 0;
 120         initrd_end = 0;
 121 }
 122 #endif /* CONFIG_BLK_DEV_INITRD */
 123
 124 static phys_addr_t dtb_early_pa __initdata;
 125
 126 void __init setup_bootmem(void)
 127 {
 128         struct memblock_region *reg;
 129         phys_addr_t mem_size = 0;
 130         phys_addr_t vmlinux_end = __pa_symbol(&_end);
 131         phys_addr_t vmlinux_start = __pa_symbol(&_start);
 132
 133         /* Find the memory region containing the kernel */
 134         for_each_memblock(memory, reg) {
 135                 phys_addr_t end = reg->base + reg->size;
 136
 137                 if (reg->base <= vmlinux_start && vmlinux_end <= end) {
 138                         mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
 139
 140                         /*
 141                          * Remove memblock from the end of usable area to the
 142                          * end of region
 143                          */
 144                         if (reg->base + mem_size < end)
 145                                 memblock_remove(reg->base + mem_size,
 146                                                 end - reg->base - mem_size);
 147                 }
 148         }
 149         BUG_ON(mem_size == 0);
 150
 151         /* Reserve from the start of the kernel to the end of the kernel */
 152         memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 153
 154         set_max_mapnr(PFN_DOWN(mem_size));
 155         max_pfn = PFN_DOWN(memblock_end_of_DRAM());
 156         max_low_pfn = max_pfn;
 157
 158 #ifdef CONFIG_BLK_DEV_INITRD
 159         setup_initrd();
 160 #endif /* CONFIG_BLK_DEV_INITRD */
 161
 162         /*
 163          * Avoid using early_init_fdt_reserve_self() since __pa() does
 164          * not work for DTB pointers that are fixmap addresses
 165          */
 166         memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
 167
 168         early_init_fdt_scan_reserved_mem();
 169         memblock_allow_resize();
 170         memblock_dump_all();
 171
 172         for_each_memblock(memory, reg) {
 173                 unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 174                 unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
 175
 176                 memblock_set_node(PFN_PHYS(start_pfn),
 177                                   PFN_PHYS(end_pfn - start_pfn),
 178                                   &memblock.memory, 0);
 179         }
 180 }
 181
 182 #ifdef CONFIG_MMU
 183 unsigned long va_pa_offset;
 184 EXPORT_SYMBOL(va_pa_offset);
 185 unsigned long pfn_base;
 186 EXPORT_SYMBOL(pfn_base);
 187
 188 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 189 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 190 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
 191 static bool mmu_enabled;
 192
 193 #define MAX_EARLY_MAPPING_SIZE  SZ_128M
 194
 195 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 196
 197 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 198 {
 199         unsigned long addr = __fix_to_virt(idx);
 200         pte_t *ptep;
 201
 202         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 203
 204         ptep = &fixmap_pte[pte_index(addr)];
 205
 206         if (pgprot_val(prot)) {
 207                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 208         } else {
 209                 pte_clear(&init_mm, addr, ptep);
 210                 local_flush_tlb_page(addr);
 211         }
 212 }
 213
 214 static pte_t *__init get_pte_virt(phys_addr_t pa)
 215 {
 216         if (mmu_enabled) {
 217                 clear_fixmap(FIX_PTE);
 218                 return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
 219         } else {
 220                 return (pte_t *)((uintptr_t)pa);
 221         }
 222 }
 223
 224 static phys_addr_t __init alloc_pte(uintptr_t va)
 225 {
 226         /*
 227          * We only create PMD or PGD early mappings so we
 228          * should never reach here with MMU disabled.
 229          */
 230         BUG_ON(!mmu_enabled);
 231
 232         return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 233 }
 234
 235 static void __init create_pte_mapping(pte_t *ptep,
 236                                       uintptr_t va, phys_addr_t pa,
 237                                       phys_addr_t sz, pgprot_t prot)
 238 {
 239         uintptr_t pte_index = pte_index(va);
 240
 241         BUG_ON(sz != PAGE_SIZE);
 242
 243         if (pte_none(ptep[pte_index]))
 244                 ptep[pte_index] = pfn_pte(PFN_DOWN(pa), prot);
 245 }
 246
 247 #ifndef __PAGETABLE_PMD_FOLDED
 248
 249 pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
 250 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 251
 252 #if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
 253 #define NUM_EARLY_PMDS          1UL
 254 #else
 255 #define NUM_EARLY_PMDS          (1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
 256 #endif
 257 pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
 258
 259 static pmd_t *__init get_pmd_virt(phys_addr_t pa)
 260 {
 261         if (mmu_enabled) {
 262                 clear_fixmap(FIX_PMD);
 263                 return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
 264         } else {
 265                 return (pmd_t *)((uintptr_t)pa);
 266         }
 267 }
 268
 269 static phys_addr_t __init alloc_pmd(uintptr_t va)
 270 {
 271         uintptr_t pmd_num;
 272
 273         if (mmu_enabled)
 274                 return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 275
 276         pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
 277         BUG_ON(pmd_num >= NUM_EARLY_PMDS);
 278         return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
 279 }
 280
 281 static void __init create_pmd_mapping(pmd_t *pmdp,
 282                                       uintptr_t va, phys_addr_t pa,
 283                                       phys_addr_t sz, pgprot_t prot)
 284 {
 285         pte_t *ptep;
 286         phys_addr_t pte_phys;
 287         uintptr_t pmd_index = pmd_index(va);
 288
 289         if (sz == PMD_SIZE) {
 290                 if (pmd_none(pmdp[pmd_index]))
 291                         pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pa), prot);
 292                 return;
 293         }
 294
 295         if (pmd_none(pmdp[pmd_index])) {
 296                 pte_phys = alloc_pte(va);
 297                 pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
 298                 ptep = get_pte_virt(pte_phys);
 299                 memset(ptep, 0, PAGE_SIZE);
 300         } else {
 301                 pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_index]));
 302                 ptep = get_pte_virt(pte_phys);
 303         }
 304
 305         create_pte_mapping(ptep, va, pa, sz, prot);
 306 }
 307
 308 #define pgd_next_t              pmd_t
 309 #define alloc_pgd_next(__va)    alloc_pmd(__va)
 310 #define get_pgd_next_virt(__pa) get_pmd_virt(__pa)
 311 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 312         create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
 313 #define fixmap_pgd_next         fixmap_pmd
 314 #else
 315 #define pgd_next_t              pte_t
 316 #define alloc_pgd_next(__va)    alloc_pte(__va)
 317 #define get_pgd_next_virt(__pa) get_pte_virt(__pa)
 318 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 319         create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
 320 #define fixmap_pgd_next         fixmap_pte
 321 #endif
 322
 323 static void __init create_pgd_mapping(pgd_t *pgdp,
 324                                       uintptr_t va, phys_addr_t pa,
 325                                       phys_addr_t sz, pgprot_t prot)
 326 {
 327         pgd_next_t *nextp;
 328         phys_addr_t next_phys;
 329         uintptr_t pgd_index = pgd_index(va);
 330
 331         if (sz == PGDIR_SIZE) {
 332                 if (pgd_val(pgdp[pgd_index]) == 0)
 333                         pgdp[pgd_index] = pfn_pgd(PFN_DOWN(pa), prot);
 334                 return;
 335         }
 336
 337         if (pgd_val(pgdp[pgd_index]) == 0) {
 338                 next_phys = alloc_pgd_next(va);
 339                 pgdp[pgd_index] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
 340                 nextp = get_pgd_next_virt(next_phys);
 341                 memset(nextp, 0, PAGE_SIZE);
 342         } else {
 343                 next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_index]));
 344                 nextp = get_pgd_next_virt(next_phys);
 345         }
 346
 347         create_pgd_next_mapping(nextp, va, pa, sz, prot);
 348 }
 349
 350 static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
 351 {
 352         /* Upgrade to PMD_SIZE mappings whenever possible */
 353         if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
 354                 return PAGE_SIZE;
 355
 356         return PMD_SIZE;
 357 }
 358
 359 /*
 360  * setup_vm() is called from head.S with MMU-off.
 361  *
 362  * Following requirements should be honoured for setup_vm() to work
 363  * correctly:
 364  * 1) It should use PC-relative addressing for accessing kernel symbols.
 365  *    To achieve this we always use GCC cmodel=medany.
 366  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 367  *    so disable compiler instrumentation when FTRACE is enabled.
 368  *
 369  * Currently, the above requirements are honoured by using custom CFLAGS
 370  * for init.o in mm/Makefile.
 371  */
 372
 373 #ifndef __riscv_cmodel_medany
 374 #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
 375 #endif
 376
 377 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 378 {
 379         uintptr_t va, end_va;
 380         uintptr_t load_pa = (uintptr_t)(&_start);
 381         uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
 382         uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
 383
 384         va_pa_offset = PAGE_OFFSET - load_pa;
 385         pfn_base = PFN_DOWN(load_pa);
 386
 387         /*
 388          * Enforce boot alignment requirements of RV32 and
 389          * RV64 by only allowing PMD or PGD mappings.
 390          */
 391         BUG_ON(map_size == PAGE_SIZE);
 392
 393         /* Sanity check alignment and size */
 394         BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 395         BUG_ON((load_pa % map_size) != 0);
 396         BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
 397
 398         /* Setup early PGD for fixmap */
 399         create_pgd_mapping(early_pg_dir, FIXADDR_START,
 400                            (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
 401
 402 #ifndef __PAGETABLE_PMD_FOLDED
 403         /* Setup fixmap PMD */
 404         create_pmd_mapping(fixmap_pmd, FIXADDR_START,
 405                            (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
 406         /* Setup trampoline PGD and PMD */
 407         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 408                            (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
 409         create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
 410                            load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
 411 #else
 412         /* Setup trampoline PGD */
 413         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 414                            load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
 415 #endif
 416
 417         /*
 418          * Setup early PGD covering entire kernel which will allows
 419          * us to reach paging_init(). We map all memory banks later
 420          * in setup_vm_final() below.
 421          */
 422         end_va = PAGE_OFFSET + load_sz;
 423         for (va = PAGE_OFFSET; va < end_va; va += map_size)
 424                 create_pgd_mapping(early_pg_dir, va,
 425                                    load_pa + (va - PAGE_OFFSET),
 426                                    map_size, PAGE_KERNEL_EXEC);
 427
 428         /* Create fixed mapping for early FDT parsing */
 429         end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE;
 430         for (va = __fix_to_virt(FIX_FDT); va < end_va; va += PAGE_SIZE)
 431                 create_pte_mapping(fixmap_pte, va,
 432                                    dtb_pa + (va - __fix_to_virt(FIX_FDT)),
 433                                    PAGE_SIZE, PAGE_KERNEL);
 434
 435         /* Save pointer to DTB for early FDT parsing */
 436         dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK);
 437         /* Save physical address for memblock reservation */
 438         dtb_early_pa = dtb_pa;
 439 }
 440
 441 static void __init setup_vm_final(void)
 442 {
 443         uintptr_t va, map_size;
 444         phys_addr_t pa, start, end;
 445         struct memblock_region *reg;
 446
 447         /* Set mmu_enabled flag */
 448         mmu_enabled = true;
 449
 450         /* Setup swapper PGD for fixmap */
 451         create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
 452                            __pa_symbol(fixmap_pgd_next),
 453                            PGDIR_SIZE, PAGE_TABLE);
 454
 455         /* Map all memory banks */
 456         for_each_memblock(memory, reg) {
 457                 start = reg->base;
 458                 end = start + reg->size;
 459
 460                 if (start >= end)
 461                         break;
 462                 if (memblock_is_nomap(reg))
 463                         continue;
 464                 if (start <= __pa(PAGE_OFFSET) &&
 465                     __pa(PAGE_OFFSET) < end)
 466                         start = __pa(PAGE_OFFSET);
 467
 468                 map_size = best_map_size(start, end - start);
 469                 for (pa = start; pa < end; pa += map_size) {
 470                         va = (uintptr_t)__va(pa);
 471                         create_pgd_mapping(swapper_pg_dir, va, pa,
 472                                            map_size, PAGE_KERNEL_EXEC);
 473                 }
 474         }
 475
 476         /* Clear fixmap PTE and PMD mappings */
 477         clear_fixmap(FIX_PTE);
 478         clear_fixmap(FIX_PMD);
 479
 480         /* Move to swapper page table */
 481         csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
 482         local_flush_tlb_all();
 483 }
 484
 485 void free_initmem(void)
 486 {
 487         unsigned long init_begin = (unsigned long)__init_begin;
 488         unsigned long init_end = (unsigned long)__init_end;
 489
 490         /* Make the region as non-execuatble. */
 491         set_memory_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
 492         free_initmem_default(POISON_FREE_INITMEM);
 493 }
 494
 495 #else
 496 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 497 {
 498 #ifdef CONFIG_BUILTIN_DTB
 499         dtb_early_va = soc_lookup_builtin_dtb();
 500         if (!dtb_early_va) {
 501                 /* Fallback to first available DTS */
 502                 dtb_early_va = (void *) __dtb_start;
 503         }
 504 #else
 505         dtb_early_va = (void *)dtb_pa;
 506 #endif
 507 }
 508
 509 static inline void setup_vm_final(void)
 510 {
 511 }
 512 #endif /* CONFIG_MMU */
 513
 514 #ifdef CONFIG_STRICT_KERNEL_RWX
 515 void mark_rodata_ro(void)
 516 {
 517         unsigned long text_start = (unsigned long)_text;
 518         unsigned long text_end = (unsigned long)_etext;
 519         unsigned long rodata_start = (unsigned long)__start_rodata;
 520         unsigned long data_start = (unsigned long)_data;
 521         unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
 522
 523         set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
 524         set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
 525         set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
 526         set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
 527
 528         debug_checkwx();
 529 }
 530 #endif
 531
 532 void __init paging_init(void)
 533 {
 534         setup_vm_final();
 535         memblocks_present();
 536         sparse_init();
 537         setup_zero_page();
 538         zone_sizes_init();
 539 }
 540
 541 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 542 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 543                                struct vmem_altmap *altmap)
 544 {
 545         return vmemmap_populate_basepages(start, end, node);
 546 }
 547 #endif