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