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
  24 phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
  25 EXPORT_SYMBOL_GPL(memstart_addr);
  26 phys_addr_t kernstart_addr __ro_after_init;
  27 EXPORT_SYMBOL_GPL(kernstart_addr);
  28 unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
  29 EXPORT_SYMBOL_GPL(kernstart_virt_addr);
  30
  31 bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
  32 bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
  33
  34 static int __init parse_nosmep(char *p)
  35 {
  36         disable_kuep = true;
  37         pr_warn("Disabling Kernel Userspace Execution Prevention\n");
  38         return 0;
  39 }
  40 early_param("nosmep", parse_nosmep);
  41
  42 static int __init parse_nosmap(char *p)
  43 {
  44         disable_kuap = true;
  45         pr_warn("Disabling Kernel Userspace Access Protection\n");
  46         return 0;
  47 }
  48 early_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
  55 CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
  56 CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15);
  57
  58 static 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
  83 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1];
  84 EXPORT_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  */
  93 void 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 }
 130 EXPORT_SYMBOL_GPL(pgtable_cache_add);   /* used by kvm_hv module */
 131
 132 void 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 }