linux/arch/arm/mm/init.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/arch/arm/mm/init.c
   4 *
   5 *  Copyright (C) 1995-2005 Russell King
   6 */
   7#include <linux/kernel.h>
   8#include <linux/errno.h>
   9#include <linux/swap.h>
  10#include <linux/init.h>
  11#include <linux/mman.h>
  12#include <linux/sched/signal.h>
  13#include <linux/sched/task.h>
  14#include <linux/export.h>
  15#include <linux/nodemask.h>
  16#include <linux/initrd.h>
  17#include <linux/of_fdt.h>
  18#include <linux/highmem.h>
  19#include <linux/gfp.h>
  20#include <linux/memblock.h>
  21#include <linux/dma-map-ops.h>
  22#include <linux/sizes.h>
  23#include <linux/stop_machine.h>
  24#include <linux/swiotlb.h>
  25
  26#include <asm/cp15.h>
  27#include <asm/mach-types.h>
  28#include <asm/memblock.h>
  29#include <asm/memory.h>
  30#include <asm/prom.h>
  31#include <asm/sections.h>
  32#include <asm/setup.h>
  33#include <asm/set_memory.h>
  34#include <asm/system_info.h>
  35#include <asm/tlb.h>
  36#include <asm/fixmap.h>
  37#include <asm/ptdump.h>
  38
  39#include <asm/mach/arch.h>
  40#include <asm/mach/map.h>
  41
  42#include "mm.h"
  43
  44#ifdef CONFIG_CPU_CP15_MMU
  45unsigned long __init __clear_cr(unsigned long mask)
  46{
  47        cr_alignment = cr_alignment & ~mask;
  48        return cr_alignment;
  49}
  50#endif
  51
  52#ifdef CONFIG_BLK_DEV_INITRD
  53static int __init parse_tag_initrd(const struct tag *tag)
  54{
  55        pr_warn("ATAG_INITRD is deprecated; "
  56                "please update your bootloader.\n");
  57        phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
  58        phys_initrd_size = tag->u.initrd.size;
  59        return 0;
  60}
  61
  62__tagtable(ATAG_INITRD, parse_tag_initrd);
  63
  64static int __init parse_tag_initrd2(const struct tag *tag)
  65{
  66        phys_initrd_start = tag->u.initrd.start;
  67        phys_initrd_size = tag->u.initrd.size;
  68        return 0;
  69}
  70
  71__tagtable(ATAG_INITRD2, parse_tag_initrd2);
  72#endif
  73
  74static void __init find_limits(unsigned long *min, unsigned long *max_low,
  75                               unsigned long *max_high)
  76{
  77        *max_low = PFN_DOWN(memblock_get_current_limit());
  78        *min = PFN_UP(memblock_start_of_DRAM());
  79        *max_high = PFN_DOWN(memblock_end_of_DRAM());
  80}
  81
  82#ifdef CONFIG_ZONE_DMA
  83
  84phys_addr_t arm_dma_zone_size __read_mostly;
  85EXPORT_SYMBOL(arm_dma_zone_size);
  86
  87/*
  88 * The DMA mask corresponding to the maximum bus address allocatable
  89 * using GFP_DMA.  The default here places no restriction on DMA
  90 * allocations.  This must be the smallest DMA mask in the system,
  91 * so a successful GFP_DMA allocation will always satisfy this.
  92 */
  93phys_addr_t arm_dma_limit;
  94unsigned long arm_dma_pfn_limit;
  95#endif
  96
  97void __init setup_dma_zone(const struct machine_desc *mdesc)
  98{
  99#ifdef CONFIG_ZONE_DMA
 100        if (mdesc->dma_zone_size) {
 101                arm_dma_zone_size = mdesc->dma_zone_size;
 102                arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
 103        } else
 104                arm_dma_limit = 0xffffffff;
 105        arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
 106#endif
 107}
 108
 109static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
 110        unsigned long max_high)
 111{
 112        unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 113
 114#ifdef CONFIG_ZONE_DMA
 115        max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low);
 116#endif
 117        max_zone_pfn[ZONE_NORMAL] = max_low;
 118#ifdef CONFIG_HIGHMEM
 119        max_zone_pfn[ZONE_HIGHMEM] = max_high;
 120#endif
 121        free_area_init(max_zone_pfn);
 122}
 123
 124#ifdef CONFIG_HAVE_ARCH_PFN_VALID
 125int pfn_valid(unsigned long pfn)
 126{
 127        phys_addr_t addr = __pfn_to_phys(pfn);
 128
 129        if (__phys_to_pfn(addr) != pfn)
 130                return 0;
 131
 132        return memblock_is_map_memory(addr);
 133}
 134EXPORT_SYMBOL(pfn_valid);
 135#endif
 136
 137static bool arm_memblock_steal_permitted = true;
 138
 139phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
 140{
 141        phys_addr_t phys;
 142
 143        BUG_ON(!arm_memblock_steal_permitted);
 144
 145        phys = memblock_phys_alloc(size, align);
 146        if (!phys)
 147                panic("Failed to steal %pa bytes at %pS\n",
 148                      &size, (void *)_RET_IP_);
 149
 150        memblock_free(phys, size);
 151        memblock_remove(phys, size);
 152
 153        return phys;
 154}
 155
 156static void __init arm_initrd_init(void)
 157{
 158#ifdef CONFIG_BLK_DEV_INITRD
 159        phys_addr_t start;
 160        unsigned long size;
 161
 162        initrd_start = initrd_end = 0;
 163
 164        if (!phys_initrd_size)
 165                return;
 166
 167        /*
 168         * Round the memory region to page boundaries as per free_initrd_mem()
 169         * This allows us to detect whether the pages overlapping the initrd
 170         * are in use, but more importantly, reserves the entire set of pages
 171         * as we don't want these pages allocated for other purposes.
 172         */
 173        start = round_down(phys_initrd_start, PAGE_SIZE);
 174        size = phys_initrd_size + (phys_initrd_start - start);
 175        size = round_up(size, PAGE_SIZE);
 176
 177        if (!memblock_is_region_memory(start, size)) {
 178                pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
 179                       (u64)start, size);
 180                return;
 181        }
 182
 183        if (memblock_is_region_reserved(start, size)) {
 184                pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
 185                       (u64)start, size);
 186                return;
 187        }
 188
 189        memblock_reserve(start, size);
 190
 191        /* Now convert initrd to virtual addresses */
 192        initrd_start = __phys_to_virt(phys_initrd_start);
 193        initrd_end = initrd_start + phys_initrd_size;
 194#endif
 195}
 196
 197#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
 198void check_cpu_icache_size(int cpuid)
 199{
 200        u32 size, ctr;
 201
 202        asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
 203
 204        size = 1 << ((ctr & 0xf) + 2);
 205        if (cpuid != 0 && icache_size != size)
 206                pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
 207                        cpuid);
 208        if (icache_size > size)
 209                icache_size = size;
 210}
 211#endif
 212
 213void __init arm_memblock_init(const struct machine_desc *mdesc)
 214{
 215        /* Register the kernel text, kernel data and initrd with memblock. */
 216        memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
 217
 218        arm_initrd_init();
 219
 220        arm_mm_memblock_reserve();
 221
 222        /* reserve any platform specific memblock areas */
 223        if (mdesc->reserve)
 224                mdesc->reserve();
 225
 226        early_init_fdt_scan_reserved_mem();
 227
 228        /* reserve memory for DMA contiguous allocations */
 229        dma_contiguous_reserve(arm_dma_limit);
 230
 231        arm_memblock_steal_permitted = false;
 232        memblock_dump_all();
 233}
 234
 235void __init bootmem_init(void)
 236{
 237        memblock_allow_resize();
 238
 239        find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
 240
 241        early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
 242                      (phys_addr_t)max_low_pfn << PAGE_SHIFT);
 243
 244        /*
 245         * sparse_init() tries to allocate memory from memblock, so must be
 246         * done after the fixed reservations
 247         */
 248        sparse_init();
 249
 250        /*
 251         * Now free the memory - free_area_init needs
 252         * the sparse mem_map arrays initialized by sparse_init()
 253         * for memmap_init_zone(), otherwise all PFNs are invalid.
 254         */
 255        zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
 256}
 257
 258/*
 259 * Poison init memory with an undefined instruction (ARM) or a branch to an
 260 * undefined instruction (Thumb).
 261 */
 262static inline void poison_init_mem(void *s, size_t count)
 263{
 264        u32 *p = (u32 *)s;
 265        for (; count != 0; count -= 4)
 266                *p++ = 0xe7fddef0;
 267}
 268
 269static void __init free_highpages(void)
 270{
 271#ifdef CONFIG_HIGHMEM
 272        unsigned long max_low = max_low_pfn;
 273        phys_addr_t range_start, range_end;
 274        u64 i;
 275
 276        /* set highmem page free */
 277        for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 278                                &range_start, &range_end, NULL) {
 279                unsigned long start = PFN_UP(range_start);
 280                unsigned long end = PFN_DOWN(range_end);
 281
 282                /* Ignore complete lowmem entries */
 283                if (end <= max_low)
 284                        continue;
 285
 286                /* Truncate partial highmem entries */
 287                if (start < max_low)
 288                        start = max_low;
 289
 290                for (; start < end; start++)
 291                        free_highmem_page(pfn_to_page(start));
 292        }
 293#endif
 294}
 295
 296/*
 297 * mem_init() marks the free areas in the mem_map and tells us how much
 298 * memory is free.  This is done after various parts of the system have
 299 * claimed their memory after the kernel image.
 300 */
 301void __init mem_init(void)
 302{
 303#ifdef CONFIG_ARM_LPAE
 304        if (swiotlb_force == SWIOTLB_FORCE ||
 305            max_pfn > arm_dma_pfn_limit)
 306                swiotlb_init(1);
 307        else
 308                swiotlb_force = SWIOTLB_NO_FORCE;
 309#endif
 310
 311        set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
 312
 313        /* this will put all unused low memory onto the freelists */
 314        memblock_free_all();
 315
 316#ifdef CONFIG_SA1111
 317        /* now that our DMA memory is actually so designated, we can free it */
 318        free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
 319#endif
 320
 321        free_highpages();
 322
 323        /*
 324         * Check boundaries twice: Some fundamental inconsistencies can
 325         * be detected at build time already.
 326         */
 327#ifdef CONFIG_MMU
 328        BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
 329        BUG_ON(TASK_SIZE                                > MODULES_VADDR);
 330#endif
 331
 332#ifdef CONFIG_HIGHMEM
 333        BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
 334        BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
 335#endif
 336}
 337
 338#ifdef CONFIG_STRICT_KERNEL_RWX
 339struct section_perm {
 340        const char *name;
 341        unsigned long start;
 342        unsigned long end;
 343        pmdval_t mask;
 344        pmdval_t prot;
 345        pmdval_t clear;
 346};
 347
 348/* First section-aligned location at or after __start_rodata. */
 349extern char __start_rodata_section_aligned[];
 350
 351static struct section_perm nx_perms[] = {
 352        /* Make pages tables, etc before _stext RW (set NX). */
 353        {
 354                .name   = "pre-text NX",
 355                .start  = PAGE_OFFSET,
 356                .end    = (unsigned long)_stext,
 357                .mask   = ~PMD_SECT_XN,
 358                .prot   = PMD_SECT_XN,
 359        },
 360        /* Make init RW (set NX). */
 361        {
 362                .name   = "init NX",
 363                .start  = (unsigned long)__init_begin,
 364                .end    = (unsigned long)_sdata,
 365                .mask   = ~PMD_SECT_XN,
 366                .prot   = PMD_SECT_XN,
 367        },
 368        /* Make rodata NX (set RO in ro_perms below). */
 369        {
 370                .name   = "rodata NX",
 371                .start  = (unsigned long)__start_rodata_section_aligned,
 372                .end    = (unsigned long)__init_begin,
 373                .mask   = ~PMD_SECT_XN,
 374                .prot   = PMD_SECT_XN,
 375        },
 376};
 377
 378static struct section_perm ro_perms[] = {
 379        /* Make kernel code and rodata RX (set RO). */
 380        {
 381                .name   = "text/rodata RO",
 382                .start  = (unsigned long)_stext,
 383                .end    = (unsigned long)__init_begin,
 384#ifdef CONFIG_ARM_LPAE
 385                .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
 386                .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
 387#else
 388                .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
 389                .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
 390                .clear  = PMD_SECT_AP_WRITE,
 391#endif
 392        },
 393};
 394
 395/*
 396 * Updates section permissions only for the current mm (sections are
 397 * copied into each mm). During startup, this is the init_mm. Is only
 398 * safe to be called with preemption disabled, as under stop_machine().
 399 */
 400static inline void section_update(unsigned long addr, pmdval_t mask,
 401                                  pmdval_t prot, struct mm_struct *mm)
 402{
 403        pmd_t *pmd;
 404
 405        pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
 406
 407#ifdef CONFIG_ARM_LPAE
 408        pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 409#else
 410        if (addr & SECTION_SIZE)
 411                pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
 412        else
 413                pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
 414#endif
 415        flush_pmd_entry(pmd);
 416        local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
 417}
 418
 419/* Make sure extended page tables are in use. */
 420static inline bool arch_has_strict_perms(void)
 421{
 422        if (cpu_architecture() < CPU_ARCH_ARMv6)
 423                return false;
 424
 425        return !!(get_cr() & CR_XP);
 426}
 427
 428static void set_section_perms(struct section_perm *perms, int n, bool set,
 429                              struct mm_struct *mm)
 430{
 431        size_t i;
 432        unsigned long addr;
 433
 434        if (!arch_has_strict_perms())
 435                return;
 436
 437        for (i = 0; i < n; i++) {
 438                if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
 439                    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
 440                        pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
 441                                perms[i].name, perms[i].start, perms[i].end,
 442                                SECTION_SIZE);
 443                        continue;
 444                }
 445
 446                for (addr = perms[i].start;
 447                     addr < perms[i].end;
 448                     addr += SECTION_SIZE)
 449                        section_update(addr, perms[i].mask,
 450                                set ? perms[i].prot : perms[i].clear, mm);
 451        }
 452
 453}
 454
 455/**
 456 * update_sections_early intended to be called only through stop_machine
 457 * framework and executed by only one CPU while all other CPUs will spin and
 458 * wait, so no locking is required in this function.
 459 */
 460static void update_sections_early(struct section_perm perms[], int n)
 461{
 462        struct task_struct *t, *s;
 463
 464        for_each_process(t) {
 465                if (t->flags & PF_KTHREAD)
 466                        continue;
 467                for_each_thread(t, s)
 468                        if (s->mm)
 469                                set_section_perms(perms, n, true, s->mm);
 470        }
 471        set_section_perms(perms, n, true, current->active_mm);
 472        set_section_perms(perms, n, true, &init_mm);
 473}
 474
 475static int __fix_kernmem_perms(void *unused)
 476{
 477        update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
 478        return 0;
 479}
 480
 481static void fix_kernmem_perms(void)
 482{
 483        stop_machine(__fix_kernmem_perms, NULL, NULL);
 484}
 485
 486static int __mark_rodata_ro(void *unused)
 487{
 488        update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
 489        return 0;
 490}
 491
 492void mark_rodata_ro(void)
 493{
 494        stop_machine(__mark_rodata_ro, NULL, NULL);
 495        debug_checkwx();
 496}
 497
 498#else
 499static inline void fix_kernmem_perms(void) { }
 500#endif /* CONFIG_STRICT_KERNEL_RWX */
 501
 502void free_initmem(void)
 503{
 504        fix_kernmem_perms();
 505
 506        poison_init_mem(__init_begin, __init_end - __init_begin);
 507        if (!machine_is_integrator() && !machine_is_cintegrator())
 508                free_initmem_default(-1);
 509}
 510
 511#ifdef CONFIG_BLK_DEV_INITRD
 512void free_initrd_mem(unsigned long start, unsigned long end)
 513{
 514        if (start == initrd_start)
 515                start = round_down(start, PAGE_SIZE);
 516        if (end == initrd_end)
 517                end = round_up(end, PAGE_SIZE);
 518
 519        poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
 520        free_reserved_area((void *)start, (void *)end, -1, "initrd");
 521}
 522#endif
 523