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