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/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         phys_addr_t start;
  99         unsigned long size;
 100
 101         /* Ignore the virtul address computed during device tree parsing */
 102         initrd_start = initrd_end = 0;
 103
 104         if (!phys_initrd_size)
 105                 return;
 106         /*
 107          * Round the memory region to page boundaries as per free_initrd_mem()
 108          * This allows us to detect whether the pages overlapping the initrd
 109          * are in use, but more importantly, reserves the entire set of pages
 110          * as we don't want these pages allocated for other purposes.
 111          */
 112         start = round_down(phys_initrd_start, PAGE_SIZE);
 113         size = phys_initrd_size + (phys_initrd_start - start);
 114         size = round_up(size, PAGE_SIZE);
 115
 116         if (!memblock_is_region_memory(start, size)) {
 117                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
 118                        (u64)start, size);
 119                 goto disable;
 120         }
 121
 122         if (memblock_is_region_reserved(start, size)) {
 123                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
 124                        (u64)start, size);
 125                 goto disable;
 126         }
 127
 128         memblock_reserve(start, size);
 129         /* Now convert initrd to virtual addresses */
 130         initrd_start = (unsigned long)__va(phys_initrd_start);
 131         initrd_end = initrd_start + phys_initrd_size;
 132         initrd_below_start_ok = 1;
 133
 134         pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
 135                 (void *)(initrd_start), size);
 136         return;
 137 disable:
 138         pr_cont(" - disabling initrd\n");
 139         initrd_start = 0;
 140         initrd_end = 0;
 141 }
 142 #endif /* CONFIG_BLK_DEV_INITRD */
 143
 144 static phys_addr_t dtb_early_pa __initdata;
 145
 146 void __init setup_bootmem(void)
 147 {
 148         struct memblock_region *reg;
 149         phys_addr_t mem_size = 0;
 150         phys_addr_t total_mem = 0;
 151         phys_addr_t mem_start, end = 0;
 152         phys_addr_t vmlinux_end = __pa_symbol(&_end);
 153         phys_addr_t vmlinux_start = __pa_symbol(&_start);
 154
 155         /* Find the memory region containing the kernel */
 156         for_each_memblock(memory, reg) {
 157                 end = reg->base + reg->size;
 158                 if (!total_mem)
 159                         mem_start = reg->base;
 160                 if (reg->base <= vmlinux_start && vmlinux_end <= end)
 161                         BUG_ON(reg->size == 0);
 162                 total_mem = total_mem + reg->size;
 163         }
 164
 165         /*
 166          * Remove memblock from the end of usable area to the
 167          * end of region
 168          */
 169         mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET);
 170         if (mem_start + mem_size < end)
 171                 memblock_remove(mem_start + mem_size,
 172                                 end - mem_start - mem_size);
 173
 174         /* Reserve from the start of the kernel to the end of the kernel */
 175         memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 176
 177         max_pfn = PFN_DOWN(memblock_end_of_DRAM());
 178         max_low_pfn = max_pfn;
 179         set_max_mapnr(max_low_pfn);
 180
 181 #ifdef CONFIG_BLK_DEV_INITRD
 182         setup_initrd();
 183 #endif /* CONFIG_BLK_DEV_INITRD */
 184
 185         /*
 186          * Avoid using early_init_fdt_reserve_self() since __pa() does
 187          * not work for DTB pointers that are fixmap addresses
 188          */
 189         memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
 190
 191         early_init_fdt_scan_reserved_mem();
 192         memblock_allow_resize();
 193         memblock_dump_all();
 194
 195         for_each_memblock(memory, reg) {
 196                 unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 197                 unsigned long end_pfn = memblock_region_memory_end_pfn(reg);
 198
 199                 memblock_set_node(PFN_PHYS(start_pfn),
 200                                   PFN_PHYS(end_pfn - start_pfn),
 201                                   &memblock.memory, 0);
 202         }
 203 }
 204
 205 #ifdef CONFIG_MMU
 206 unsigned long va_pa_offset;
 207 EXPORT_SYMBOL(va_pa_offset);
 208 unsigned long pfn_base;
 209 EXPORT_SYMBOL(pfn_base);
 210
 211 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 212 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
 213 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
 214 static bool mmu_enabled;
 215
 216 #define MAX_EARLY_MAPPING_SIZE  SZ_128M
 217
 218 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
 219
 220 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
 221 {
 222         unsigned long addr = __fix_to_virt(idx);
 223         pte_t *ptep;
 224
 225         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 226
 227         ptep = &fixmap_pte[pte_index(addr)];
 228
 229         if (pgprot_val(prot)) {
 230                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
 231         } else {
 232                 pte_clear(&init_mm, addr, ptep);
 233                 local_flush_tlb_page(addr);
 234         }
 235 }
 236
 237 static pte_t *__init get_pte_virt(phys_addr_t pa)
 238 {
 239         if (mmu_enabled) {
 240                 clear_fixmap(FIX_PTE);
 241                 return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
 242         } else {
 243                 return (pte_t *)((uintptr_t)pa);
 244         }
 245 }
 246
 247 static phys_addr_t __init alloc_pte(uintptr_t va)
 248 {
 249         /*
 250          * We only create PMD or PGD early mappings so we
 251          * should never reach here with MMU disabled.
 252          */
 253         BUG_ON(!mmu_enabled);
 254
 255         return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 256 }
 257
 258 static void __init create_pte_mapping(pte_t *ptep,
 259                                       uintptr_t va, phys_addr_t pa,
 260                                       phys_addr_t sz, pgprot_t prot)
 261 {
 262         uintptr_t pte_idx = pte_index(va);
 263
 264         BUG_ON(sz != PAGE_SIZE);
 265
 266         if (pte_none(ptep[pte_idx]))
 267                 ptep[pte_idx] = pfn_pte(PFN_DOWN(pa), prot);
 268 }
 269
 270 #ifndef __PAGETABLE_PMD_FOLDED
 271
 272 pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
 273 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
 274
 275 #if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
 276 #define NUM_EARLY_PMDS          1UL
 277 #else
 278 #define NUM_EARLY_PMDS          (1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
 279 #endif
 280 pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
 281
 282 static pmd_t *__init get_pmd_virt(phys_addr_t pa)
 283 {
 284         if (mmu_enabled) {
 285                 clear_fixmap(FIX_PMD);
 286                 return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
 287         } else {
 288                 return (pmd_t *)((uintptr_t)pa);
 289         }
 290 }
 291
 292 static phys_addr_t __init alloc_pmd(uintptr_t va)
 293 {
 294         uintptr_t pmd_num;
 295
 296         if (mmu_enabled)
 297                 return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 298
 299         pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
 300         BUG_ON(pmd_num >= NUM_EARLY_PMDS);
 301         return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
 302 }
 303
 304 static void __init create_pmd_mapping(pmd_t *pmdp,
 305                                       uintptr_t va, phys_addr_t pa,
 306                                       phys_addr_t sz, pgprot_t prot)
 307 {
 308         pte_t *ptep;
 309         phys_addr_t pte_phys;
 310         uintptr_t pmd_idx = pmd_index(va);
 311
 312         if (sz == PMD_SIZE) {
 313                 if (pmd_none(pmdp[pmd_idx]))
 314                         pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pa), prot);
 315                 return;
 316         }
 317
 318         if (pmd_none(pmdp[pmd_idx])) {
 319                 pte_phys = alloc_pte(va);
 320                 pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
 321                 ptep = get_pte_virt(pte_phys);
 322                 memset(ptep, 0, PAGE_SIZE);
 323         } else {
 324                 pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_idx]));
 325                 ptep = get_pte_virt(pte_phys);
 326         }
 327
 328         create_pte_mapping(ptep, va, pa, sz, prot);
 329 }
 330
 331 #define pgd_next_t              pmd_t
 332 #define alloc_pgd_next(__va)    alloc_pmd(__va)
 333 #define get_pgd_next_virt(__pa) get_pmd_virt(__pa)
 334 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 335         create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
 336 #define fixmap_pgd_next         fixmap_pmd
 337 #else
 338 #define pgd_next_t              pte_t
 339 #define alloc_pgd_next(__va)    alloc_pte(__va)
 340 #define get_pgd_next_virt(__pa) get_pte_virt(__pa)
 341 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
 342         create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
 343 #define fixmap_pgd_next         fixmap_pte
 344 #endif
 345
 346 static void __init create_pgd_mapping(pgd_t *pgdp,
 347                                       uintptr_t va, phys_addr_t pa,
 348                                       phys_addr_t sz, pgprot_t prot)
 349 {
 350         pgd_next_t *nextp;
 351         phys_addr_t next_phys;
 352         uintptr_t pgd_idx = pgd_index(va);
 353
 354         if (sz == PGDIR_SIZE) {
 355                 if (pgd_val(pgdp[pgd_idx]) == 0)
 356                         pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(pa), prot);
 357                 return;
 358         }
 359
 360         if (pgd_val(pgdp[pgd_idx]) == 0) {
 361                 next_phys = alloc_pgd_next(va);
 362                 pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
 363                 nextp = get_pgd_next_virt(next_phys);
 364                 memset(nextp, 0, PAGE_SIZE);
 365         } else {
 366                 next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_idx]));
 367                 nextp = get_pgd_next_virt(next_phys);
 368         }
 369
 370         create_pgd_next_mapping(nextp, va, pa, sz, prot);
 371 }
 372
 373 static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
 374 {
 375         /* Upgrade to PMD_SIZE mappings whenever possible */
 376         if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
 377                 return PAGE_SIZE;
 378
 379         return PMD_SIZE;
 380 }
 381
 382 /*
 383  * setup_vm() is called from head.S with MMU-off.
 384  *
 385  * Following requirements should be honoured for setup_vm() to work
 386  * correctly:
 387  * 1) It should use PC-relative addressing for accessing kernel symbols.
 388  *    To achieve this we always use GCC cmodel=medany.
 389  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 390  *    so disable compiler instrumentation when FTRACE is enabled.
 391  *
 392  * Currently, the above requirements are honoured by using custom CFLAGS
 393  * for init.o in mm/Makefile.
 394  */
 395
 396 #ifndef __riscv_cmodel_medany
 397 #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
 398 #endif
 399
 400 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 401 {
 402         uintptr_t va, end_va;
 403         uintptr_t load_pa = (uintptr_t)(&_start);
 404         uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
 405         uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
 406
 407         va_pa_offset = PAGE_OFFSET - load_pa;
 408         pfn_base = PFN_DOWN(load_pa);
 409
 410         /*
 411          * Enforce boot alignment requirements of RV32 and
 412          * RV64 by only allowing PMD or PGD mappings.
 413          */
 414         BUG_ON(map_size == PAGE_SIZE);
 415
 416         /* Sanity check alignment and size */
 417         BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 418         BUG_ON((load_pa % map_size) != 0);
 419         BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
 420
 421         /* Setup early PGD for fixmap */
 422         create_pgd_mapping(early_pg_dir, FIXADDR_START,
 423                            (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
 424
 425 #ifndef __PAGETABLE_PMD_FOLDED
 426         /* Setup fixmap PMD */
 427         create_pmd_mapping(fixmap_pmd, FIXADDR_START,
 428                            (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
 429         /* Setup trampoline PGD and PMD */
 430         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 431                            (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
 432         create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
 433                            load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
 434 #else
 435         /* Setup trampoline PGD */
 436         create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
 437                            load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
 438 #endif
 439
 440         /*
 441          * Setup early PGD covering entire kernel which will allows
 442          * us to reach paging_init(). We map all memory banks later
 443          * in setup_vm_final() below.
 444          */
 445         end_va = PAGE_OFFSET + load_sz;
 446         for (va = PAGE_OFFSET; va < end_va; va += map_size)
 447                 create_pgd_mapping(early_pg_dir, va,
 448                                    load_pa + (va - PAGE_OFFSET),
 449                                    map_size, PAGE_KERNEL_EXEC);
 450
 451         /* Create fixed mapping for early FDT parsing */
 452         end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE;
 453         for (va = __fix_to_virt(FIX_FDT); va < end_va; va += PAGE_SIZE)
 454                 create_pte_mapping(fixmap_pte, va,
 455                                    dtb_pa + (va - __fix_to_virt(FIX_FDT)),
 456                                    PAGE_SIZE, PAGE_KERNEL);
 457
 458         /* Save pointer to DTB for early FDT parsing */
 459         dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK);
 460         /* Save physical address for memblock reservation */
 461         dtb_early_pa = dtb_pa;
 462 }
 463
 464 static void __init setup_vm_final(void)
 465 {
 466         uintptr_t va, map_size;
 467         phys_addr_t pa, start, end;
 468         struct memblock_region *reg;
 469
 470         /* Set mmu_enabled flag */
 471         mmu_enabled = true;
 472
 473         /* Setup swapper PGD for fixmap */
 474         create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
 475                            __pa_symbol(fixmap_pgd_next),
 476                            PGDIR_SIZE, PAGE_TABLE);
 477
 478         /* Map all memory banks */
 479         for_each_memblock(memory, reg) {
 480                 start = reg->base;
 481                 end = start + reg->size;
 482
 483                 if (start >= end)
 484                         break;
 485                 if (memblock_is_nomap(reg))
 486                         continue;
 487                 if (start <= __pa(PAGE_OFFSET) &&
 488                     __pa(PAGE_OFFSET) < end)
 489                         start = __pa(PAGE_OFFSET);
 490
 491                 map_size = best_map_size(start, end - start);
 492                 for (pa = start; pa < end; pa += map_size) {
 493                         va = (uintptr_t)__va(pa);
 494                         create_pgd_mapping(swapper_pg_dir, va, pa,
 495                                            map_size, PAGE_KERNEL_EXEC);
 496                 }
 497         }
 498
 499         /* Clear fixmap PTE and PMD mappings */
 500         clear_fixmap(FIX_PTE);
 501         clear_fixmap(FIX_PMD);
 502
 503         /* Move to swapper page table */
 504         csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
 505         local_flush_tlb_all();
 506 }
 507 #else
 508 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 509 {
 510 #ifdef CONFIG_BUILTIN_DTB
 511         dtb_early_va = soc_lookup_builtin_dtb();
 512         if (!dtb_early_va) {
 513                 /* Fallback to first available DTS */
 514                 dtb_early_va = (void *) __dtb_start;
 515         }
 516 #else
 517         dtb_early_va = (void *)dtb_pa;
 518 #endif
 519 }
 520
 521 static inline void setup_vm_final(void)
 522 {
 523 }
 524 #endif /* CONFIG_MMU */
 525
 526 #ifdef CONFIG_STRICT_KERNEL_RWX
 527 void mark_rodata_ro(void)
 528 {
 529         unsigned long text_start = (unsigned long)_text;
 530         unsigned long text_end = (unsigned long)_etext;
 531         unsigned long rodata_start = (unsigned long)__start_rodata;
 532         unsigned long data_start = (unsigned long)_data;
 533         unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
 534
 535         set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
 536         set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
 537         set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
 538         set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
 539
 540         debug_checkwx();
 541 }
 542 #endif
 543
 544 void __init paging_init(void)
 545 {
 546         setup_vm_final();
 547         memblocks_present();
 548         sparse_init();
 549         setup_zero_page();
 550         zone_sizes_init();
 551 }
 552
 553 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 554 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 555                                struct vmem_altmap *altmap)
 556 {
 557         return vmemmap_populate_basepages(start, end, node);
 558 }
 559 #endif