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