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