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