LXR linux/arch/powerpc/mm/init-common.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  PowerPC version
   4 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   5 *
   6 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   7 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   8 *    Copyright (C) 1996 Paul Mackerras
   9 *
  10 *  Derived from "arch/i386/mm/init.c"
  11 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  12 *
  13 *  Dave Engebretsen <engebret@us.ibm.com>
  14 *      Rework for PPC64 port.
  15 */
  16
  17#undef DEBUG
  18
  19#include <linux/string.h>
  20#include <linux/pgtable.h>
  21#include <asm/pgalloc.h>
  22#include <asm/kup.h>
  23
  24phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
  25EXPORT_SYMBOL_GPL(memstart_addr);
  26phys_addr_t kernstart_addr __ro_after_init;
  27EXPORT_SYMBOL_GPL(kernstart_addr);
  28unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
  29EXPORT_SYMBOL_GPL(kernstart_virt_addr);
  30
  31bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
  32bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
  33
  34static int __init parse_nosmep(char *p)
  35{
  36        disable_kuep = true;
  37        pr_warn("Disabling Kernel Userspace Execution Prevention\n");
  38        return 0;
  39}
  40early_param("nosmep", parse_nosmep);
  41
  42static int __init parse_nosmap(char *p)
  43{
  44        disable_kuap = true;
  45        pr_warn("Disabling Kernel Userspace Access Protection\n");
  46        return 0;
  47}
  48early_param("nosmap", parse_nosmap);
  49
  50#define CTOR(shift) static void ctor_##shift(void *addr) \
  51{                                                       \
  52        memset(addr, 0, sizeof(void *) << (shift));     \
  53}
  54
  55CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
  56CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15);
  57
  58static inline void (*ctor(int shift))(void *)
  59{
  60        BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15);
  61
  62        switch (shift) {
  63        case 0: return ctor_0;
  64        case 1: return ctor_1;
  65        case 2: return ctor_2;
  66        case 3: return ctor_3;
  67        case 4: return ctor_4;
  68        case 5: return ctor_5;
  69        case 6: return ctor_6;
  70        case 7: return ctor_7;
  71        case 8: return ctor_8;
  72        case 9: return ctor_9;
  73        case 10: return ctor_10;
  74        case 11: return ctor_11;
  75        case 12: return ctor_12;
  76        case 13: return ctor_13;
  77        case 14: return ctor_14;
  78        case 15: return ctor_15;
  79        }
  80        return NULL;
  81}
  82
  83struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1];
  84EXPORT_SYMBOL_GPL(pgtable_cache);       /* used by kvm_hv module */
  85
  86/*
  87 * Create a kmem_cache() for pagetables.  This is not used for PTE
  88 * pages - they're linked to struct page, come from the normal free
  89 * pages pool and have a different entry size (see real_pte_t) to
  90 * everything else.  Caches created by this function are used for all
  91 * the higher level pagetables, and for hugepage pagetables.
  92 */
  93void pgtable_cache_add(unsigned int shift)
  94{
  95        char *name;
  96        unsigned long table_size = sizeof(void *) << shift;
  97        unsigned long align = table_size;
  98
  99        /* When batching pgtable pointers for RCU freeing, we store
 100         * the index size in the low bits.  Table alignment must be
 101         * big enough to fit it.
 102         *
 103         * Likewise, hugeapge pagetable pointers contain a (different)
 104         * shift value in the low bits.  All tables must be aligned so
 105         * as to leave enough 0 bits in the address to contain it. */
 106        unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
 107                                     HUGEPD_SHIFT_MASK + 1);
 108        struct kmem_cache *new;
 109
 110        /* It would be nice if this was a BUILD_BUG_ON(), but at the
 111         * moment, gcc doesn't seem to recognize is_power_of_2 as a
 112         * constant expression, so so much for that. */
 113        BUG_ON(!is_power_of_2(minalign));
 114        BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
 115
 116        if (PGT_CACHE(shift))
 117                return; /* Already have a cache of this size */
 118
 119        align = max_t(unsigned long, align, minalign);
 120        name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
 121        new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
 122        if (!new)
 123                panic("Could not allocate pgtable cache for order %d", shift);
 124
 125        kfree(name);
 126        pgtable_cache[shift] = new;
 127
 128        pr_debug("Allocated pgtable cache for order %d\n", shift);
 129}
 130EXPORT_SYMBOL_GPL(pgtable_cache_add);   /* used by kvm_hv module */
 131
 132void pgtable_cache_init(void)
 133{
 134        pgtable_cache_add(PGD_INDEX_SIZE);
 135
 136        if (PMD_CACHE_INDEX)
 137                pgtable_cache_add(PMD_CACHE_INDEX);
 138        /*
 139         * In all current configs, when the PUD index exists it's the
 140         * same size as either the pgd or pmd index except with THP enabled
 141         * on book3s 64
 142         */
 143        if (PUD_CACHE_INDEX)
 144                pgtable_cache_add(PUD_CACHE_INDEX);
 145}
 146