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